CLhc il. il i^ill Xibranj ^.'ovlll (inrnliiia ^iatr Qlnlicc\ 5D371 534 SOI 948786 0 hl^ny^ This BOOK may be kept out TWO WEEKS ONLY, and is subject to a fine of FIVE CENTS a day thereafter. It is due on the day indicated below: OCT 2 1196^ NOV 5 »y^^ SCHLIOH'S MANUAL OF FORESTRY. SCHLICH'S MANUAL OF FORESTEY, VOLUME II. SYLVICULTUPvE. W. SCHLICH, Ph.D., C.I.E., F.E.S, F.L.S., PRINCIPAL PROFESSOR OF FORESTRY AT THE ROYAL IMDIAX ENGINEERING COLLEGE, COOPERS hill; LATE INSPECTOR-GENERAL OF FORESTS TO THE GOVERN- MENT OF INDIA; HONORARY PROFESSOR OF FORESTRY AT THE ROYAL AGRICULTURAL COLLEGE, CIRENCESTER. THIRD EDITION. REVISED. WITH 87 ILLUSTRATIONS. LOXDOX : BRADBUEY, AGNEW, & CO. Ld., 10, BOUVEEIE STREET. 1904. BRADBURY, AONEW, & CO. LD., PRINTERS, LONDON AND TONBRIDOE. TABLE OF CONTENTS. PAGE INTRODUCTION 1 PART I.— THE FOUND ATIONS OF SYLVICULTURE . 3 Chapter I.— Locality in Relation to Forest Vegetation . . 7 Section I. — The Atmosphere ....... 8 Section II. — Climate 11 1. Heat 12 2. Light 17 3. Moisture 20 4. Air Currents 22 Section JII.— Soil 23 1. Origin of Soil 24 2. Formation of Indigenous Soil . . . . . 24 3. Composition of Soil . . . . . . . 26 4. Physical Properties of Soil ...... 29 5. Classification of Soils . . . . . . . 31 Sectimi IV. — Effect of the Soil upon Forest Vegetation . . 34 Section V. — Effect of Forest Vegetation upon the Locality . . 41 Section VI. — Assessment of the Quality of the Locality . . 45 Chapter II. — Development of Forest Trees 52 1. Shape 52 2. Height Growth 54 .3. Diameter Growth 57 4. Volume Growth 59 5. Duration of Life 62 6. Reproductive Power 64 Chapter III. — Character and Composition of Woods . . 69 Sectimi I. — Pure Woods 69 Section II.— Mixed Woods 71 1. Advantages of Mixed Woods 71 2. Disadvantages of Mixed Woods 73 3. Rules for the Formation of Mixed Woods . . . 74 4. Mixtures of Shade-bearing Species . . . .77 5. Mixtures of Shade-bearing with Light-demanding Species . . . . . . . • . . 79 6. Mixtures of Light-demanding Species . . .85 39925 VI TAIU.K or CONTENTS. PAGK Chapter IV.— Thk Sylviccltur.'VL Svstkms, or Mkthods of Tkkatmknt 89 Section I. — Description of Systems ...... 90 1. Clear Cutting ill High Forest 90 2. The Shelter-wood Compartment System . 9-3 3. The Shelter-wood Group System 94 4. The Shelter-wood Selection System . . .96 5. The Coppice System 97 G. The Coppice with Standard System . . 99 7. High Forest with Standards 102 8. Two-storied High Forest 103 9. High Forest with Soil-protection Wood . . 104 10. Forestry Combined with the Growing of Field Crops . 104 11. Forestry Combined with Pasture 107 12. Forestry Combined with the Rearing of Game . . 107 Section //.—Choice of System 107 PART II. FORMATION AND REGENERATION OF WOODS. 113 Chapter I.— riacLiMiNAiiv \VoiiK.s 116 Section I. — Choice of Species 116 Section //.—Fencing 122 Section III. — Reclamation of the Soil 129 1. Treatment of an Impermeable Substratum . . 130 2. Treatment of Swampy Ground Generally . . . 131 3. Irrigation of Arid Land 137 4. Treatment of Excessive Accumulations of Vegetable Matter 138 5. Fixation of Shifting Sands 139 6. Fixation of Unstable Soil on Slopes .... 143 Chapter II.— Artificial Formation of Woods 145 Section I. — Direct Sowing 145 A. Conditions of Success 145 1. Choice of Species 145 2. Quality of Seed 145 3. Quantity of Seed 149 4. Conditions of Germination . . ]51 B. Methods of Sowing 157 1. Broadcast Sowing 157 2. Partial Sowing 162 Section //.-Planting 169 A. Conditions of Success 169 1. Choice of Species . . . ,170 2. Different Kinds of Plants 170 3. Quality of Plants .171 4. Age and Size of Plants 172 TABLE OF CONTENTS. Vll Chapter II. — continued. page Section II. — Planting — continued. A. Conditions of Success — continued. 5. Season for Planting ....... 173 6. Density of Planting 174 7. Distribution of Plants over the Area . . . . 175 8. Number of Plants 181 9. Lifting Plants 183 10. Pruning Plants 186 11. Protection of Plants in Transit ..... 188 12. Preparation of the Soil ...... 190 B. Raising Plants 190 1. Purchase of Plants 190 2. Plants taken from Existing Woods . . . . 191 8. Raising Plants in Nurseries 192 C. Methods of Planting 208 1. Planting with Balls of Earth 210 2. Planting without Balls of Earth 211 3. Mound Planting 2] 9 D. Planting of Slips, Layers and Suckers ..... 220 Chapter III. — Natural Regeneration of Woods .... 223 Section I. — Natural Regeneration by Seed 223 A. Natural Regeneration under Shelter- woods . . . 223 1. The Compartment or Uniform System . . . . 225 2. The Strip System 237 3. The Group System 239 4. The Selection System 243 5. Comparative Merits of the Four Systems . . . 244 B. Natural Regeneration from Adjoining Woods . . . 247 Section II. — Natural Regeneration by Shoots and Suckers . . 250 Chapter IV. — Formation of Mixed Woods 254 1. Formation of Even Aged Mixed Woods . . . . 254 2. Formation of Uneven Aged Mixed Woods . . . 258 Chapter V. — Choice of Method of Formation 261 Section I. — Choice between Direct Sowing and Planting . . 262 Section II. — Choice between Artificial Regeneration and Natural Regeneration by Seed . . . . . . 266 Section III. — Combination of Several Methods of Formation . 268 PART III.— TENDING OF WOODS 271 Chapter I. — Tending of Woods during Early Youth . . . 276 1. Protection against External Dangers .... 276 2. Preservation of a Proper Density of the Crop . . 278 3. Cleaning of Young Woods 279 4. Preservation of a Proper ^Mixture 280 VI 11 TABLE OF CONTENTS. PAGE Chapter II.— Tending of Crowded Woods after Early Age . 281 Section /.—Removal of Dead, Dying, or Otherwise Undesirable Trees 281 Sectio7i 77.— Pruning 283 Section 777.— Thinning 288 1. General 288 2. The Most Suitable Growing Space 289 .3. The Theory of Thinning 292 4. Thinning of Mixed Woods 296 5. Thinning of Coppice Woods 297 6. Principal Advantages of Thinning 298 7. Execution of Thinnings 299 Chapter III. — Tending of Open Woods for the Production OF Large Timber 30i) 1. The Theory 390 2. Principal Forms of Treatment 302 3. Execution of the Work 305 PART IV.-SYLVICULTURAL NOTES ON BRITISH FOREST TREES 307 1. Beech 310 2. Hornbeam 315 3. Oak 319 1. Ash 325 5. Ehn 328 G. Sweet Chestnut 331 7. Maple 334 8. Common Alder 336 9. Birch 340 10. Willow 343 11. Poplar 346 1-J. Lime-tree 349 13. Hazel 351 14. Silver Fir 353 15. Spruce 358 16. Scotch Pine 363 17. Black or Austrian Pine 368 18. Corsican Pine ........ 371 I'J. Weymouth Pine 372 20. Larch 375 21. Douglas Fir 381 INDEX 389 SYLVICULTURE INTKODUCTION. Sylviculture literally means the culture of forests, that is to say, all measures connected with the formation, preserva- tion and treatment of forests. In practice, however, the word forestry is used to express and comprise all this, while by sylviculture, in its narrower sense, is understood the formation, regeneration and tending of forests, or woods, until they become ripe for the axe. Sylviculture, in the latter sense, teaches how a forest, or wood, can be produced and guided to maturity so as to realise in the most advantageous manner the object which the proprietor has in view. The object for which a particular forest is maintained depends on the will and pleasure of the owner, in so far as his freedom of action is not limited by rights of third persons, or by legal enactments. The object itself can be one of many, and of these the following may be mentioned by way of illustration : — 1. To yield produce of a definite description, for instance trees and shrubs of special beauty, or trees giving a certain kind of timber, or other produce, fit for particular purposes, such as grass, turpentine, caoutchouc, etc. 2. To produce the greatest possible quantity of wood, or other produce, per acre and year. 3. To produce the highest possible money return per acre and year. 4. To produce the highest possible interest on the invested capital. 5. To produce certain indirect eft'ects ; for instance, to s. K Library _ N. C. St-Lt.(- OollfiiT.. 2 INTRODUCTION. influence the climate, to regulate the drainage of the country, to prevent landslips or avalanches, to arrest shifting sands, etc. In each of these and other eases the particular species of tree to be grown and the method of treatment are likely to differ, and it is the business of the forester to select those species and methods which realise the object of management most fully and in the most economic manner. More especially, the forester must always consider what effect the species and the selected method of treatment are likely to have on the property, and he must remember that any exceptional strain put upon the soil for more than a limited period, in order to realise an exceptional effect, must be followed by a corre- sponding period of relaxation. Unless this is given, the soil, in the majority of cases, will deteriorate, and it may ulti- mately become absolutely sterile. Such an exceptional strain may suit the special requirements of a particular owner, but is not in the interest of the general community. Political Economy teaches, that the correct mode of procedure points to the careful preservation of the productive powers (or factors) of any given locality, so as to render possible the production of the same effect, or an increased one, regularly and indefinitely. Experience has shown that in forestry the safest method of preserving the productive powers of a locality consists in maintaining uninterruptedly a crop of forest vegetation on the area. The more frequently and the longer the ground is uncovered and exposed to the full effects of sun and air currents, the more, in the majority of cases, is the productive power liable to be reduced. The subject of Sylviculture will be treated under the following headings : — Part I. — The Foundations of Sylviculture. II. — Formation and Regeneration of Woods. ,, III. — Tending of Woods. TV.— Sylvicultural Notes on British Forest Trees. PAKT I. THE FOUNDATIONS OF SYLVICULTURE. b2 THE FOUNDATIONS OF 8YLYICULTUEE. The natural forest vegetation of the various parts of the earth consists of a large number of species of trees and shrubs, each of which has its peculiar mode of gro\Yth, and thrives best under certain conditions. Only a limited number of species of trees possess the faculty of forming by themselves healthy and flourishing woods, ^Yhile others will obtain perfec- tion only if they are mixed with the former. Species are called ruling, or dependent, according to whether they belong to the first or second category. Owing to the great number of species and the ever-changing conditions in different parts of the earth, it would be altogether impracticable to deal with all in a book which has for its object to teach the theory of sylvi- culture. The general principles of sylviculture hold good all over the world, but the illustrations must be taken from a limited area. In the present volume they will be taken chiefly from the timber trees ordinarily growing in Western Europe on the fiftieth degree of northern latitude, and the countries immediately to the north and south of it. If the more important species of timber trees growing in that region are classified in accordance with what has been said above, the following lists are obtained : — Riding Species. Decidedly ruling. — Silver fir, beech, spruce, Scotch pine. Conditionally ruling. — Hornbeam, oak, larch, common alder, birch, willows, Austrian pine, mountain pine, Weymouth pine, Douglas fir. Dependent Species. Of these may be mentioned : Ash, Norway maple, sycamore, sweet chestnut, poplars, elms, lime, white alder, Cembran pine, etc. 6 THE FOUNDATIONS OF SYLVICLLTUllE. Althougli the biological characteristics of these and other species have been carefully studied for many years past, the subject has been by no means exhausted, because the factors which affect the growth of trees vary constantly, and moreover some of these factors are as yet imperfectly understood. The experience so far gathered will be found in the succeeding chapters. It is that experience which must guide the forester in the selection of species for a particular locality, and of the subsequent method of treatment. The subjects which claim more immediate attention will be dealt with in the following four chapters : — Chapter I. — Locality in Relation to Forest Vegetation. ,, II. — The Development of Forest Trees. ,, III. — Character and Composition of Woods. ,, IV. — The Sylvicultural Systems. These are matters which govern all forest operations, not only the formation, regeneration, and tending of woods, but also the determination of the yield, the preparation of working plans, and the ultimate utilisation of the forest produce. CHAPTEE I. LOCALITY IN RELATION TO FOREST VEGETATION. When a plant germinates on the surface of the earth, it sends its roots into the soil, and its stem into the air. The soil, assisted hy the subsoil, provides to the plant the means of stability and nourishment ; the atmosphere overlying the soil furnishes certain nourishing substances, heat, light, and moisture. Hence soil, including subsoil, and atmosphere are the media which act upon forest vegetation, and they together are in sylviculture called the " localiti/." The active agencies or factors of the locality depend on tjie nature of the soil and the climate, the latter being governed by the situation. The sum total of these factors represents the quality or yield capa- city of the locality. The forester requires to be well acquainted with the manner in which soil and climate act on forest vege- tation, in order to decide in each case which species and method of treatment are best adapted, under a given set of conditions, to yield the most favourable results. The detailed considera- tion of the laws which govern this branch of forestry finds a place in the auxiliary sciences, such as Physics, Chemistry, Meteorology, Mineralogy, and Geology. A sufficient know- ledge of these branches of science is assumed, so that here only their application to Sylviculture need be considered. The chapter has been divided into the following sections : — Section I. — The Atmosphere. ,, II. — Climate. III.— Soil. ,, IV. — Eliect of the Locality on Forest Vegetation. ,, V. — Effect of Forest Vegetation on the Locality. ,, VI. — Assessment of the Quality of the Locality. 8 LUCALITY AND FOKEST VEGETATION. Section I. — Tiik Atmosphere. The earth is surrounded by gaseous bodies, which move with it, and collectively are termed the atmosphere. Owing to the weight of its component parts, the atmosphere is densest close to the surface of the earth, and l)ecomes tliiimer with increasing distance from the earth passing gradually into space. The atmosphere consists essentially of the following substances : — (1.) Oxygen and Nitrogen. (2.) Carbon dioxide. (3.) Water, in various conditions. (4.) Solid bodies. (5.) Ammonia and Nitric Acid. 1. O.rijficii (iinl Xili'Dficii. The chief constituents of the atmosphere are 21 parts of oxygen and 79 parts of nitrogen in a mechanical mixture, as well as small quantities of argon, helion, and other substances. The latter have quite lately been discovered, and it would be beyond the scope of this book to discuss them licrc. No chemical process is required to separate oxygen from nitrogen ; as a matter of fact, all porous bodies possess the faculty of taking oxygen from the atmosphere, without entering into a chemical combination with it. Amongst such bodies are the soil, leaves, bark, and roots of plants. Until a comparatively late date it was believed that plants could not take nitrogen direct from the air. It has now been proved tliat certain plants, including various forest trees, can do this, and further investigation will doubtlessly lead to additional discoveries in this respect. Although tlie leaves of plants take up oxygen, tliey exhale greater quantities of it under the effect of light ; the latter is the result of the decomposition of carbon dioxide by the leaves, which retain the carbon and surrender the oxygen. Thus, plants are powerful agents in the productit)n of oxygen. THE ATMOSPHERE. 9 The action of the air in the soil is chiefly two-fold ; it causes the evaporation of moisture, and the decomposition of organic matter. The air which penetrates into the fissures and inter- stices of the soil becomes laden with vapour and carbon dioxide ; it is then forced out of the soil b}' every rise of temperature, and replaced bj^ fresh air during cooling. The extent of this change of air depends on the degree of porosity of the soil and the daily range of temperature ; the greater these are, the more rapidly will moisture and organic matter (humus) disappear. The daily range of temperature is seriously affected by the degree of protection which the soil receives from forest vegetation ; it is greatest in fully exposed soils and smallest in soils under the shelter of a crowded crop of trees, especially if the foliage offers lateral as well as vertical shelter against sun and air currents. In the latter case the humus is generally carefully preserved, in the former it disappears rapidly. 2. Carhon Dioxide. About 0*0004 parts of the volume of the atmosphere consist of carbon dioxide, which is received from a variety of sources, as combustion or decomposition of plants, the breathing of animals, volcanoes, spring water issuing from the interior of the earth, combustion of coal and lignite, from various minerals, as for instance calcium carbonate. Of these, the first is by far the most important source of supply. Plants, except certain parasites and saprophytes, take the carbon dioxide which they require through their leaves from the atmosphere. Subsequently, when they die and are decom- posed, their carbon is converted back into carbon dioxide, and returned to the atmosphere ; hence plants form an important link in the movement of carbon dioxide. 3. Moisture. The atmosphere is the medium through which the dry land receives the greater part of the necessary moisture. 10 LOCALITY AND FOIIKST VJ-KiKTATlOX. Sheets of water (the sea, lakes, rivers, etc.) and moist bodies evaporate moisture, which, as vapour, rises in the atmosphere, until it is again condensed into water. It either settles as dew on cool objects, or falls as rain, snow, or hail from the cloud region to the ground. Plants, being moist bodies, take part in the circulation of moisture ; they receive it from the soil through the roots, and evaporate it through the leaves. In this perpetual circular motion of moisture, several points are of special interest to the forester. By the action of heat water is converted into vapour, and consequently evaporating bodies become drier and cooler, and reduce the temperature of the surrounding layers of air in their effort to replace the expended heat. It follows that the rate of evaporation is, amongst other influences, governed by the temperature, which depends upon the climate. There is, how- ever, another reason why the rate of evaporation depends on the temperature : — The maximum of vapour which saturated air can hold rises at a more rapid rate than the increase in temperature. If, for instance, one cubic foot of air is saturated with vapour when it contains "15 grams of water at freezing jjoint (32^ F.), it can hold "28 grams at a temperature of 54^ degrees, and "(U grams at 77 degrees. It follows that air of a high temperature can hold more vapour than at a low temperature, and yet the relative, humidity may be smaller in the former case. Hence evaporation is more rapid in summer than in winter : it is generally also greater during the day than at night. 4. Solid JUhUcs. Tlie atmosphere always contains a certain (juaiitity of organic and inorganic solid ])odies, which are kept in suspen- sion in conseijuence of their minute size and lightness. AVhen vapour is condensed and falls to the ground as rain, snow, or hail, it carries with it a certain ipiantity of these solid bodies, which differs according to locality ; the mineral part of these deposits is not inconsiderable compared with that wliicli CLIMATE. 11 is required annually for the production of timber on a fully- stocked area. Amongst the substances thus brought to the ground are calcium carbonate, magnesium carbonate, sodium chloride, calcium sulithate, ferric oxide, alumina, silica, organic nitrogenous matter, etc. Direct analysis has shown that upwards of 800 lb. of these substances have been deposited on an acre of land in one year, a quantity more than sufficient to provide for that contained in a heavy increment of wood laid on during the same period. In other cases, observations have shown that the quantities deposited are considerably less than 300 lb. per acre. 5. Ammonia and Nitric Acid. Limited amounts of these important substances are con- tained in the atmosphere ; they supply nitrogen to forest plants in considerable quantities, especially for the formation of seeds. A certain quantity of ammonia and nitric acid is brought into the soil by the annual rainfall ; where the latter is heavy, the quantity of the above substances thus obtained by the soil may be sufficient for all the requirements of forest growth, but where it is light, this will not be the case. As already stated, certain plants (Leguminosse) can take nitrogen direct from the air by means of tubercles or nodules, which are produced by microscopic fungi or bacteria. Again, further investigation may show that mycorhiza, a coat formed by a fungus outside or inside the root, is connected with the assimilation of nitrogen by the plant. Section II. — Climate. By climate is understood the local peculiarities of the atmosphere in respect of temperature, degree of clearness, moisture and rest or motion. As already indicated, the climate of a locality depends on its situation. The climate of a locality is of greater influence upon the life 12 LOCALITY AND FOREST VEGETATION. and growth of plants than the degree of fertiUty of the soil ; hence it demands the forester's special attention. Generally speaking, the climate of a locality depends on : — (1.) Latitude and longtitude, or geographical position. (2.) Elevation ahove the level of the sea. (3.) Aspect and gradient. (4.) Shape of the surface and condition of surroundings. Each of these affects the heat, light and humidity of a locality, which are the agencies determining the commence- ment and course of the annual phenomena of vegetation. 1. IlcaL Heat affects plant life in various ways. In the first place, it is necessary for transpiration h}^ the plants and evaporation from the surface of the earth ; and secondly, it governs the movement of the air, which produces a thorough mixture of its different ingredients, as well as that of warm and cold, dry and moist, clear and hazy air. The heat required hy plants for transpiration and growth must he supplied to them hy the atmosphere, either directly or througli the soil. If these are themselves deficient in heat, transpiration must cease as soon as the plant has expended the store of heat which it contains. The latter, however, fre- quently does not take place until serious damage has l)een done to the plant, in other words, the temperature of the plant may he so far reduced that the freezing point is reached, although the temperature of the surrounding air is still several degrees above that point. The only important source of atmospheric heat is the sun ; hence the temperature of a locality depends in the first place on its latiiudc. The mean annual temperature decreases with the distance from the equator because the sun's rays strike the earth more obli(juely in proceeding iiorth oi* south from the equator towards the poles. In the centre of Europe and in the vicinity of the 50th degree of latitude, the tempera- ture decreases one degree for ul>uut every Ol miles, on HEAT. 13 proceeding north. The cHmate thus produced is frequently called the cieof/rajyliieal or solar climate. It exists practically nowhere on the earth, because it is modified and converted into the pJiysical or local climate by a series of influences, amongst which the following deserve attention : — a. Elevation above the Level of lite Sea. The temperature falls with elevation above the sea. In the Alps the fall is one degree for every 300 to 400 feet of elevation ; it is about 900 times as rapid as the fall caused by increasing latitude. The effect of elevation upon temperature is subject to modifications. High plateaux of considerable extent show a milder climate than that calculated for their elevation, because the sun's rays are more intense than at the level of the sea. On the other hand, wind currents exercise a considerable effect, so that isolated peaks have, as a rule, a comparatively rough climate. Cold air, owing to its weight, glides down slopes and may become stationary in valleys and low land generally, producing locally and temporarily a low^er temperature than that which corresponds to the elevation of the locality. Hence in such localities late and early frosts are more common than in localities which are under the influence of a free circulation of the air. h. Presence of Extenm'e Sheets of Water. Owing to a difference of temperature, and the consequent exchange of air between dry land and sheets of water, the latter cause the climate of the former to be more equable, the temperature being lower during the day and higher during the night. It is chiefly for this reason that the longitude of a locality, by affecting its distance from the ocean or other extensive sheets of water, influences the local climate. c. Aspect and Gradient. The angle at which the sun's rays strike the soil depends on the aspect of the locality ; hence, in the northern hemisphere, aspects between south-east and south-west are the warmest, 14 LOCALITY AND FOREST VEGETATION. and those between north-east and north-west the coldest. The de«:,'ree of the gradient further niodilies this effect, which also depends on the latitude. The aspect atfects the temperature also in exposing a locality to air currents, or protecting it against them. This effect may be favourable or the reverse according to the nature of the air currents. (I. Pn-scncf or Absence of Forest Vegelaiioii. Localities, which are bare of vegetation, are struck In- the full force of the sun's rays, causing the temperature at the surface of the soil to rise to the highest possible degree. At the same time, air currents sweep unimpeded over such localities, causing a rapid change of the atmosphere. On localities covered with a full crop of forest vegetation the sun's rays strike the crowns of the trees ; the heat absorbed by the air at some height above the ground, penetrates only slowly through the leaf canopy to the layer of air belo^Y it and thence to the soil. During the night again the leaf canopy prevents, or at any rate reduces, radiation. It follows that the air in forests is cooler during the day and warmer during the night, than the air on bare localities. This effect is intensified by the fact that the foliage of the trees impedes the force of air currents. Direct observations have established the following facts : — (1.) The climate of wooded countries is more ecjuuble than that of open countries. (2.) The mean temperature of soil and air in wooded countries is somewhat lower than that of soil and air in bare countries. This reduction of temperature would ordinarily act beneficially in warm southern countries, while it may become injurious in cold northern countries where the temperature is already lower than is desirable. (3.) The greatest difference occurs in summer, next in spring, then in autumn, and it is very small in winter. It follows that in forests the commencement of vegetation in HEAT. 15 spring is retarded. This may be beneficial in preventing damage b}' spring frosts, limiting the formation of inferior spring wood, etc. ; on the other hand it shortens the growing season, and delays the sprouting of seeds in spring.* Heat is a most powerful agency in the distribution of plants on the earth ; the species change with increasing latitude, elevation and other influences which govern the temperature. This applies to forest trees as well as other plants. Attempts have been made to ascertain the absolute sum of heat required annually by the more important forest trees, which have been enumerated in the introduction of this part, but so far the available data are not of much practical use in sylviculture. Moreover, it is beyond doubt, that mean temperatures are much less important to forest trees than the extremes of temperature which occur in a particular locality, more especially during the growing season. Something more definite is known of the relative heat requirements of the several species. According to Gayer this is as follows : — It is (jreatest in : Common elm, sweet chestnut, pedun- culate oak. Someichat smaller in : Sessile oak, Austrian pine, silver fir, beech, Weymouth pine, lime, Scotch pine. Less again in : Norway maple, birch, sycamore, ash, alder, hornbeam, spruce. Smallest in : Larch, Cembran jjine, mountain pine. The different degrees of heat requirement produce many phenomena of interest to the forester, of which the following may be mentioned : — (1.) On the same latitude the several species, if left to natural selection, are found at different elevations. While the Cembran pine finds full development near the ujjper limit of tree vegetation (up to 7,000 feet in the Alps), the larch and next the spruce prefer a somewhat lower zone ; lower again appear beech, silver fir and sessile oak, wliile * For further details on these questions, see Vohime I. 16 LOCALITY AND FOREST VErTETATION. tlie pedunculate oak and Scotch pine tlouiisli in the low- lands. (2.) A species which jnefers a certain altitude in one locality, will descend towards the level of the sea with increasing latitude, or ascend with decreasing latitude. (3.) At the same altitude, the more heat requiring species will seek the warmer southern aspects, and the less heat requiring species the cooler northern ones. (4.) A species, which is naturally found on a northern aspect at a low elevation, will seek a southern aspect at a higher altitude. It must not, however, be overlooked, that the actual dis- tribution is affected by many other influences besides heat, and that the above theories are only of an abstract nature. The effect of frost on the various species is intimately connected with their heat requirement. Trees suffer, as a rule, little from winter frosts within the region of their natural distribution, but frost which occurs during the growing season may do considerable damage ; especially during spring (late frosts), immediately after the tender leaves and shoots have been put forth, and during autumn (early frosts), before the newly-formed wood has had time to ripen. Many influences and circumstances contribute towards the occurrence of late and early frosts. Sometimes they are caused locally, especially in low lying or confined localities in consequence of excessive radiation, evaporation, the descent of cold air from higher localities, and absence of air currents ; in other cases they are due to cold winds. The several species vary much in their bearing towards late and early frosts ; in a general way the following classification will hold good : — Most sulijtrt to suffer from laic aud carlij frosts arc : Ash, acacia, sweet chestnut, beech, silver fir. Somewhat less : Oak, Douglas fir, Norway maple, sycamore, spruce, alder. Least: Lime, hornbeam, elm, birch, larch, aspen, Corsican, Ausli-ian, Weymouth, and Scotch pines. LIGHT. ]7 The degree of damage depends, apart from the severity of the frost, on the condition of the leaves and yomig wood, the general health and vigour of the plants, and whether they have been suddenly or gradually deprived of shelter. The damage occurs, generally, during the process of thawing after freezing. The more rapidly the plant thaws, the greater will be the damage ; hence it will be greatest on east and south aspects, and smallest on west and north aspects. Frost may kill the plant outright, or only the leaves and tender shoots. It may also cause cracks in the bark, as in beech, or in the bark and wood, as in oak. 2. Lifjht. The earth receives light from the sun, the source whence heat is supplied. With the exception of certain low forms, all plants require light to enable them to live and grow, as soon as the available reserve materials have been consumed. Without light carbon dioxide cannot be decomposed by the chlorophyll of the plants. During the process of germination light is not required, because the embryo is developed by means of substances deposited in the seed. Similarly, the first starting of vege- tation in spring can take place with a small amount of light, because it is done by means of reserve materials deposited in certain parts of the plant. As soon as these substances, both in germination and the awakening of vegetation in spring, have been consumed, light becomes absolutely necessary for the preparation of new food materials. All trees, then, require light for their proper development, but the necessary quantity has its upper and lower limit. Not only too little but also too much light can interfere with the phenomena of growth. Between the maximum and minimum a degree exists which corresponds with the most favourable development of a species, and which represents its normal light requirement. Eegarding the absolute quantity 18 LOCAI.ITY AND Fdl^HST VEGETATION. of lifiht required by the several species little is known at present, but much experience has been collected which demonstrates their relative light requirements. On 'the whole it is known that certain species cannot thrive unless the.v enjoj' a large measure of light throughout life, while others will bear a certain amount of shade. Accordingly, the former species are termed lijiht dcinandhui, and the latter sliade hcariuii or tolrnitiiif/. In a general way it may be said, that trees with a dense crown are shade Ijearing, and those with a thin crown light demanding, though the light requirement does not always stand exactly in inverse proportion to the density of the crown. Some species, which are shade bearing, require a certain amount of shelter, or protection, during early youth ; they have therefore been called " shade demanding." Such a definition is, however, misleading, as these plants require protection against heat and cold, and not against light as such. In young plants of beech and silver lir, for instance, transpiration frequently reaches such a high degree, if they are not sheltered, that they lose water more quickly than they can take it up from the soil, and consequently die. Hence they require either a thorough wetting of the soil, or shelter. In tlie former case more water is availal)le, and in the latter the temperature and thereby the transpi- ration is reduced. Species are called tender or luirdi/, according as to whether they require shelter during early life, or can do without it. By summing up the available experience of the light requirements of a number of species, scales have been prepared by various authors, which, though generally agree- ing, differ somewhat in details. The following scale begins with the most light demanding species and finishes with the most shade bearing. Lime and Weymouth pine stand in the centre of this scale; the species above them are considered light demanding, and those below shade bearing, the degree in each case depending on the distance from the centre line. LIGHT. 19 (1.) Larch, birch. (2.) Scotch pine, aspen, willows, Corsican pine. (3.) Oak, ash, sweet chestnut, mountain pine. (4.) Elm, common alder, Austrian pine. (5.) White alder, lime, Weymuutli pine, Norway maple, sycamore, Cembran pine, hazel, Douglas fir. (6.) Spruce, hornbeam. (7.) Beech. (8.) Silver fir. (9.) Yew. The above scale represents only general averages. In reality the degree of light requirement is subject to considerable modifications caused by the peculiarities of each locality. Generally, all species bear more shade on good fresh soil than on poor dry ground, a fact which is indicated by the density of the crown. The Scotch pine, for instance, grown in fresh soils in countries near the sea looks quite different from the same tree seen in continental countries, and stands considerably more shade than the latter. The length of the growing season also influences the degree to which a tree will stand shade. A certain total quantity of light is required to complete the annual cycle of development, hence a more energetic effect of light is wanted in localities with a short growing season, such as high eleva- tions, or high latitudes. A species which stands a certain amount of shade at the level of the sea and in a southern climate, may become light demanding at a considerable elevation, or in a northern climate. Again, in foggy air, under a usually covered sky, or on northern aspects, the same species stands less shade than in usually clear air, under a sunny sky, or on southern aspects. In this respect it must be remembered that the actual intensity of the light is somewhat greater in high mountains than in low lands. The health of the trees is also of importance. Strong healthy plants with a good root system stand more shade, and for a longer period, than weak plants. c2 SiO LOCALITY AND FOREST VEGETATION. Lir!;ht and sliade in relation to tree growth are of the greatest importance in practical sylviculture, especially in the regeneration and tending of woods, the composition of mixed woods, etc. In each of these cases the light require- ment of the species must be fully considered, or serious mistakes may be made. The most important period in this respect is early youth, because at that time several species require some shelter, either against heat or frost. If that shelter, on the other hand, is excessive the young trees may be permanently injured, or even die. When a plant has stood in shade for some time, the activity of its leaves is reduced, and it takes some time, after the removal of the shelter, before the increased light produces increased assimilation and visible activity, because fresh organs, fitted for the altered conditions, must be produced. In all such cases it is best to remove the cover gradually and not all at once. If the plant has stood in shade for a considerable period, it may be no longer capable of developing into a tree of normal size. As long as several strong buds are found, especially near the top, this is not to be feared, but the recovery of plants witli a few miserable buds may be considered as hopeless. 8. Moisture. The Ih-st question for consideration is, whether moisture in the air is directly necessary or beneficial to plant life. The investigation of this problem meets M'ith great difiiculty, because it is often difficult to separate the effect of air moisture from that of' soil moisture. As a matter of fact, only meagre data are available as far as trees are concerned. It is known that some species, such as spruce, alder, maple, ash, and next to these, silver fir, beech and birch, thrive generally better in moist than in dry air. It is also a fact, that spruce appears naturally over extensive areas in high situations and near the sea shores of northern Europe, that is to say, in localities with a comparatively moist air, while MOISTURE. 21 it thrives but indifferently in continental situations with a dry air. The Scotch pine, on the other hand, appears over extensive tracts in continental dry climates, and at the same time flourishes in the moist insular climate of Great Britain. Although further investigation is necessary to show whether, or to what degree, trees take up moisture through their organs above ground, the atmospheric moisture is of the highest importance, for the following two reasons : — (a.) It governs the degree of transpiration from the leaves of the trees. (b.) It supplies the soil with water, whence it is taken up by the roots of the trees. Apart from the temperature, the degree of transpiration depends on the degree of saturation of the air ; hence relatively dry air causes rapid transpiration, while the latter ceases as soon as the air becomes saturated. The degree of transpiration, in its turn, governs the rapidity with which fresh water laden with raw materials is taken up by the roots. The soil receives water from the atmosphere in the shape of precipitations, as dew, rain, snow, hail, and a certain amount by means of its hygroscopic nature. The quantities differ enormously in different climates and localities, from almost nothing to over 500 inches a year. Precipitation cannot take place unless the air becomes saturated. The phenomena which favour an increase in the relative humidity, and thereby induce saturation, are active evaporation and a reduction of temperature. On the one hand, evaporation causes a reduc- tion of temperature, and on the other a falling temperature reduces the degree of evaporation ; the result is, that saturation and precipitation occur only locally. As a general rule a low temperature means a high degree of relative humidity ; hence the latter is greater in winter than in summer; greater at high elevations than in low lands; greater in the vicinity of extensive sheets of water than in 22 LOCALITY AND FOREST VROETATION. contiiK'iitiil {'ouiitries ; n;reater in forest countries than in l»are tracts. Direct observations have shown that the rehxtive liuniidily of forest air is greater than that of open air, the difference amounting in Central Euroi:)e to as much as 10 per cent, during summer, and a])Out lialf that amount in winter. The practical vahie of this fact in sylviculture is, that radiation of heat is much slower in moist than in dry air; hence tlie danger of late and early frosts is smaller in the former than in the latter. Snow and ice have a considerable effect upon trees. During early youth snow may protect forest plants against excessive cold. Afterwards a heavy fall of snow, or the formation of ice or rime, may break the branches and tops of trees, or even fell them to the ground. 4. Air Currents. The atmosphere is, practically, in constant motion. The principal cause of this is the uneven heating of the earth by the sun. The heat, which becomes free on or near the surface of the earth, w^arms the adjoining air and causes it to rise, its place being taken by colder air from other parts of the earth. The ascending air, after cooling, sinks again in its tuin. In this manner a circular motion exists between the equator and the jioies. Owing to a combination of these currents with the motion of the earth, modified wind directions are produced. The prevailing wind directions on the northern hemisphere are, llicreforc, from the south-west and the north-east, according as to whether the original current started from the tropics or the polar region. A second cause of wind currents, especially of storms or gales, is the sudden condensation of considerable quantities of aqueous vapour, which forces air to rush from all sides into the space of reduced pressure. Air currents arc of paramount importance to all organic life on the earth, because they produce a thorough mixture of SOIL, 23 the constituents of the atmosphere. Without them, the land would soon lose all moisture. The motion of the atmosphere ensures a proper distribution of moisture, carbon dioxide, oxygen and nitrogen over the earth. Air currents affect forest trees injuriously principally in two ways : — (a.) By unfavourably modifying the temperature and moisture of a locality. (b.) By injuring, breaking, bending, or overturning them. Dry winds frequently reduce the moisture of a locality to a dangerous degree ; moist and cold winds may reduce the temperature, and thus interfere with the healthy growth of the trees. Strong winds may break the leading shoots or side branches, cause trees to assume a curved shape, or even throw single trees and whole woods to the ground. The damage done to trees by strong winds differs very considerably according to species. Shallow rooted trees, like the spruce, suffer most, while deep rooted trees, like oak or Scotch pine, are much less affected. The most dangerous winds in Western Europe are those which blow from south- west, west, and north-west. Occasionally north-east winds are also dangerous. Section III. — Soil. It has been already stated that plants, and more especially trees, require a certain layer of soil, into which their roots penetrate, and which provides them with nourishment and the means of stability. Wherever this layer of soil is deep enough to meet the above requirements, the subsoil is only of indirect importance, but in the case of shallow soils the subsoil has, as a rule, to undertake part of the ordinary functions of the soil. Under any circumstances, the subsoil furnishes the materials from which the mineral parts of the soil are principally derived. Hence, in speaking of the soil, the subsoil is more or less included. :14- LOCALITY AND FOREST VEGETATION. 1. ()ri;iln of Soil. All soil is origiiiiiUy the result of the disintegration of the rocks of the earth, ^Yith the addition of certain organic sub- stances. In some cases the soil now overlies the rock from which it has been derived, in others it has been carried away by violent convulsions, or the action of water and air currents, and deposited again in other places. In the former case the soil is called " indifie no ks,'' and in the latter " cov^u'." The most important form of the latter is alluvial soil, formed b}' deposits near the sea coast, in river deltas and inland by water courses and lakes, as well as by the action of air currents. 2. Formation of Indigenous Soil. The formation of soil is due to a variety of agencies, which are either of a mechanical, chemical, or organic nature. a. Mi'cJianiml At/rncics. Amongst these, heat takes the foremost place. The heating of rocks produces an unequal strain and pressure, which cause them to burst in various directions. Then, if water penetrates into the interstices and freezes, it forces the particles asunder, thus further breaking up the rock. "Water is also a powerful agency owing to its dissolving action. h. Clicmiral Afjcn'irs. Wlien oxygen and water, wliicli contains carbon dioxide and other acids, come into contact with tlio rock, they form chemical combinations with its elements. The oxygen acts especially on the metals (as compounds of iron), forming, by the addition of water, hydrates of metallic oxides. This process, accompanied by an increase of volume, destroys the previous cohesion of the rock. Water containing carbon dioxide and other acids penetrates the rock, dissolves its various constituents and carries off various substances, such as \mo, miignc.sia and jiotash. FORMATION OF SOIL. 25 The rate of chemical decomposition depends on the tempera- ture ; the higher the latter, the quicker the decomposition. Hence it is far more rapid in tropical than in cold climates. r. Organic Afienriefi. When mechanical and chemical action have commenced the decomposition of the rock, organic action sets in. Lichens, followed by mosses, appear on the surface of the rock, which further accelerate disintegration by keeping the surface moist. Next, the roots of these plants penetrate into the finest fissures and assist mechanical action. In this manner a soil is gradually formed, which consists of fragments of rock and remnants of dead plants, suitable for the support of more highly organised plants, such as grasses and herbs ; these are followed by shrubs and trees, which penetrate with their roots deeper and deeper into the rents and fissures of the rock, and further accelerate disintegration. When this process has gone on for a sufficient length of time, the outer part of the earth's crust consists of a layer of varying depth, which, commencing from below, changes gradually from the solid rock into broken rock, or brash, then into smaller pieces of rock, or subsoil, and ultimately into the formed or surface soil. At first sight it would appear, that the composition and quality of the soil depend solely on the composition of the original rock, out of which it has been formed. This is, on closer investigation, found to be tlie case only to a limited extent, because, in the first place, certain important substances, such as potash, magnesia, lime, may be carried away and lost during the process of disintegration ; secondly, organic sub- stances are added ; and thirdly, the fertility of the soil depends not only on its chemical composition, but also, and often chiefly so, on its physical properties. All that can be said is, that certain kinds of rock yield ordinarily a soil of a certain description, but subject to modifications, which depend on the peculiarities of each case. On the whole, the attempt of 26 LOCALITY AND FOREST VEGETATION. estimating the qiialitj^of a soil l)y its geological origin only has almost invariably failed, since tiie same rock may produce soils of varying chemical composition and physical properties. ;}. ('i»)ip(>Hiti()ii III' Soil. Soil consists generally of the following substances : — (a.) Mineral matter, taken from the decomposed rock, or carried to the area by water and air currents. (b.) Organic matter, being remnants of plants and animals, (c.) AVater, partly liquid, partly in the shape of vapour. (d.) Gases, such as air, carbon dioxide and ammonia. A. Mineral Subsf/mces in Ihc Soil. . The mineral substances form, in the majority of cases, the greater part of the soil ; they may be arranged into the following four groups : — {a.) Earths. {},.) Salts. (c.) Acids. (ii/ imntJd is formed by the action of an excessive supply of air, or rather absence of moisture, on certain plants, such as heather. Acid humus is the result of deeomposition, if there is an excess of moisture and a deficiency of air in the soil. Only mild forest humus acts altogether favourably upon forest vegetation. C. ]Valn: Water is the most important component part of the soil, as plant life is impossible without a certain (piantity of moisture. It affects vegetation principall}" in the following manner : — {(I.) It assists in the decomposition of the rocks. (/>.) It assists in the formation of humus, and regulates botli the admission of air into the soil and its temperature. (r.) It is an important agent in the process of nourishing and shaping the plant. More; especially' it carries through the roots the mineral substances from the soil into the plant. However favourably a certain degree of moisture in the soil may act, an excess of water, especially if stagnant, is always injurious; it reduces the activity of the soil (by driving out air), lowers the temperature, increases danger from frost, and is lial)le to render the soil acid. The soil receives water from one or more of tlu^ following sources : — (1.) From the atmosphere, as dew, rain, snow, hail, or as vapour condensed by the hygroscopic action of the soil. (2.) From ground water resting in the subsoil. PHYSICAL PROPERTIES OF SOIL. 29 (3.) From inundations, whether natural or artiliciaL Water derived from the atmosphere acts most favourably', provided the supply is suitably distributed over the different seasons of the year, and the soil is capable of retaining mois- ture sufficiently long during dry weather. Where these con- ditions are wanting, ground water is likely to act more favour- ably, because it produces a more even degree of moisture in the upper layers of the soil. Natural inundation water is, in many cases, objectionable, because it renders the soil too wet at one time, and too dry at others. Artificial inundation, or irrigation, produces very favourable results, but it is generally expensive. D. Gases. The gases, such as air, carbon dioxide and ammonia, have been dealt with in section I. of this chapter. It is only neces- sary to add, that the amount of air in the soil varies within wide limits, and that the amount of carbon dioxide depends on the quantity of organic matter in the soil, and the rate at which it is decomposed. 4. PJiysical Properties of Soil. The principal physical properties of importance in sylvi- culture are the following : — a. C'o)isisfefic//, or binding power, the cohesion between the different particles of the soil. It depends on the chemical composition of the different parts, the degree of division, and the quantity of moisture in the soil. Generally, it is greatest in clay and smallest in sand. An admixture of humus moderates both extremes. b. Sliriiikinij, or the reduction of the volume of the soil imder the process of drying. It causes cracks in the soil, followed by the exposure of the roots. Heavy soils crack more than light soils. 30 LOCALITY AND FOREST VEGETATION. r. Ca)yiiiiii In hohl Wafer. It is generally proportional to the percentage of tine earth and humus in the soil. >/. HlfijrOftropicill/, or the capacity of the soil to attract and condense aqueous vapour from the atmosphere. It depends on the degree of division of the particles, and on the temperature. The liner the division, the greater the hygroscopicity ; more vapour is condensed at a low than at a high temperature. Soils rich in humus show the greatest hygroscopicity, next clay, then loam, then lime soils, and it is smallest in sand. e. TenarHi/ in reUtinhuj Moisture is greatest in clay soils, moderate in calcareous soils and smallest in sand. /. I'lrmeahilitji, or the capacity to let water pass through, is greatest in sand, especially if of a coarse grain, and smallest in clay. Humus soil approaches clay, while calcareous soils and loam stand about half-way betw^een the two extremes. Stiff clays are liable to be altogether impermeable ; in many cases the clay of a mixed soil is gradually carried into the subsoil, where it forms an impermeal)le layer, frequently bound together by oxide of iron. (J. The Power to retain Satta dissolved in Water depends on the proportion of line earth in the soil. //. 'Hie ( 'aparitij to liccome Heated is greatest in sand, and smallest in clay. Calcareous soils approach sand ; loam approaches clay. Sand and calcareous soils are generally hot soils, while clay is a cold soil. /. (li)ierat. Depth intensities the etliect of the various physical proper- ties. A depth of 4 feet may be considered as sufficient for almost any species, and many can do with considerably less. CLASSIFICATION OF SOILS. 31 Where a sufficient depth of soil is not available, the direct assistance of the subsoil is called in, especially its degree of permeability. The depth depends chiefly upon the nature of the rock and soil, the stratification of the rock, the situation, and the general shape of the surface of the ground. The nature of the I'ock governs the rate at which it is disinte- grated, and the rock may be more or less permeable. An impermeable subsoil is all the more injurious the nearer it is to the surface, because it makes the surface soil too wet and cold at one time, and too dry and hot at others, apart from the fact that the roots may not find sufficient room for spreading, or that the stability of trees may be endangered. A vertical stratification and a much crumpled state of the rock act most favourably upon the movements of water in the soil and the penetration of the roots ; a horizontal stratification, if unaccompanied by crumpling, is generally the least favour- able form. Low lands have ordinarily deeper soils than high lands. On ridges and steep slopes the soil is liable to be washed away, while it is collected in depressions. In the former places the covering of dead leaves is lialjle to be blown away by wind. All physical properties are of special importance through their action upon moisture. In this respect the chemical composition of the soil is of less importance than the admixture of humus and the degree of division of the particles, whether the latter are fine or coarse grained. It is for this reason that sand and clay represent, ordinarily, the extremes. 6. Classi/icatioii of Soils. For the purposes of sylviculture soils may be classified, either according to their chemical composition, or according to one or other of their physical properties. a. Classififutioii according to Chemical Coui/iosi/iu/i. It is, of course, out of the question to attempt a classifica- tion according to all component substances, nor is it necessary, •3-Z LOCALITY AND FOREST VEGETATION. because the importance of the four substances, sand, clay, Hme and humus, outweighs that of all other substances so much, that the latter need not be taken into account in this place. The subjoined table gives the composition of the ten principal classes of soils (according to Church) : — Percentage of : 1 NamoorSoil. Clay. Cal.-.ium Carbonate. Sand. Organic Matter. 1 1. Loams or Free Soil _ 20—30 5—10 50—70 2—.". ' 2. Clays _ over 40 under 5 under 50 2 .-) 3. Clav-sands ,. 3(1 .") 50—70 2— r. 4. Marls „ 30 .-)— 10 under 50 •2 .-. 5. Peaty Clay ., 30 under :> „ 50 over 5 a. Sands niidiT in ") over 80 2-.-. 7. Calcareous Sands .. HI .".— 10 ., 70 2—5 j 8. Peaty Sands . .. 10 under ."> :, 70 over 5 9. Calcareous .. 10 over 10 50-70 2—5 10. Peats ., 10 under 5 under 50 over 35 Note .—Lime improves 2. 8, '> and 8. Draining improves 2, 4, ") and 10. Irrigation improves 6 and 7. Soils of sul)ordinate importance are : — Dolomite, a chalky loam with much magnesium carl)onate. Gypsum, a soil which is rich in calcium sulphate. Salt soil, which contains an excessive percentage of salts, especially sodium chloride. Farmginous soil, which contains an excessive proportion of ferric oxide. According to the preponderance of one or other of the principal ingredients, numerous subdivisions have been made, such as sandy, or marly clays ; loamy sand, sandy loam, marly sand, sandy marl, etc. Clay, loam and calcareous soil are, as a rule, minerally strong soils, while sandy soils are less strong, liuiuus soil may be mild, dry, or sour humus soil ; the lirst acts very favourably upon tree growth, the two latter unfavourably. CLASSIFICATION OF SOILS. 33 Soils may also be classified according to the rapidity with which the humus is decomposed, as : — Very active soils : Such as dry porous sand and calcareous soils, in which the decomposition of humus is excessively quick. Active soils : Such as moderately moist loamy sand, sandy loam and loamy marl, in which the decomposition of humus proceeds at a rate favourable for growth, without actually exhausting the supply of organic matter. Moderately active soils : Such as stiff clay, wet soil, heather soil, where the decomposition is too slow for a healthy development of most plants. Inactive soils : Such as peat soil, shifting sand, etc., in which, either from excess of moisture or absence of humus and rest, little or no decomposition takes place. b. Classificafion accordinij to Physiral Properties. Of the various physical properties the degrees of consistency and of moisture are of special importance in sylviculture. According to consistency, soils may be classified in the following manner : — Light soils : All soils which contain much coarse grained sand or much humus. Loose soils : Such as peat and moor soils, which are elastic and swell during rainy weather ; they are also much lifted by frost. Binding soils : Soils of moderate cohesion, such as fine grained loamy sands, coarser grained sandy loams, calcareous soils, especially marl. Heavy soils : Such as fine grained loam, clay with coarse sand. Stif soils : Such as clay with a limited quantity of fine grained sand. In classifying soils according to the degree of moisture, a distinction must be made between the average degree of s. D 3i LOCALITY AND FOREST VEGETATION. moisture and the condition of the soil during the growing season, as set forth in the following arrangement : — JVet sail : Water flows from it without the application of pressure. — Even in summer water runs off in drops on the application of pressure. Moist .sail : On pressure being applied, water falls in drops. — During summer the soil does not become dry beyond one inch below the surface. Frc'sJt soil : Leaves traces of moisture on the palm of the hand on being pressed. — During summer it does not become dry beyond six inches below the surface. Dnj suil : Has lost the dark colour due to the presence of moisture, but does not fall to dust on being broken. — In summer it becomes dry to a depth of 12 inches within a week after a good soaking rain. Arid soil : Falls to dust on being broken. — In summer it dries up to a depth of more than 12 inches within a few days after a good soaking rain. Section' IY. — Effect of the Soil li-on Eohest Vegetation. In estimating the efifect wliicli differently constituted soils have upon forest vegetation, and more especially ui)on tree growth, the forester is guided by the demands made by the trees upon the soil. Ordinarily the soil sliould provide the tree with : — (a.) Stability. {b.) Space for a suitable spreading of the root system. {<:.) Moisture, in suitable quantities at all times. {(l.) Nourishing substances, in sufficient quantities and in a condition suitable for absorption by the roots. Any soil which meets these requirements is fertile for sylvicul- tural purposes, and experience has shown, that fertile forest soil must possess the following properties : — (J.) A sufficient depth. EFFECT OF SOIL ON FOREST VEGETATION. 35 (2.) A suitable degree of porosity. (3.) A suitable degree of moisture. (4.) A suitable chemical composition. 1. Siirjirieiif Depth. The depth is measured by the thickness of the layer of soil, and of that portion of the subsoil which can be pene- trated by the roots. In due proportion to depth are the space available for the root system, the store of nourishing sub- stances, the stability of the trees, and the state of moisture in the soil. The root sj'stem differs considerably in the several species ; some develop a tap root, which is maintained for a shorter or longer period, such as oak, elm, Scotch pine, silver fir, maple, sycamore, ash, lime, larch ; others have strong side roots, which send down deep going rootlets, such as alder ; others again go to a moderate depth, as beech, hornbeam, aspen and birch ; finally some spread altogether near the surface, such as spruce. The nature, composition and degree of moisture of the soil modify the root system to some extent, which in young trees frequently differs from that in older trees. On the whole, certain species thrive well only in deep soil, while others can subsist in shallow soil, though they prefer the former. The best indicator of the depth of soil is the height growth. A sufficient depth produces full height growth ; with deficiency of depth the height growth falls oft". Hess* classifies the trees as follows, in respect of their demands for depth of soil : — Species wkicli are satisfied icitli shalloic soils : Spruce, mountain pine, birch, aspen, mountain ash. Species ichich require moderate depth : Austrian pine, Wey- mouth pine, beech, hornbeam, black poplar, tree willows, alder, horse chestnut. * Encyklopadie imd Methodologiu der Foist wisseuschaft, by Dr. Kichard Hess, 1«8S. D 2 36 LOCALITY AND FOREST VEGETATION. S2)eci<'s which require fjrcater deptli : Scotch pine, Cembran pine, elms, Norway maple, sycamore, white poplar. Species irldclt rcindre (jreatest depth : Silver tir, larch, ash, lime, sweet chestnut, and especially oaks. At the same time, the roots of these species go rarely to a :lepth of 4 feet below the surface, unless they do not find sufficient moisture in the upper layers of the soil, a case occurring in countries with a long dry season. 2. .1 suitable Deyree of Porosity. Neither too firm nor too loose soils are favourable for tree growth. Too firm soils make the penetration of the roots difficult, if not altogether impossible, prevent the admission of the necessary air, interfere with the movement of water, and incline towards swampiness, accompanied by increased danger from frost, and by strong shrinking and cracking in summer. Too loose soils endanger the stability of the trees, are liable to be carried away by water or wind, suffer from too rapid drying and too rapid decomposition of the humus, and the plants growing in it are subject to frost lifting. The best soils are of middling consistency, such as loam and calcareous soils with a good layer of humus. 3. A suitable Degree oj Moisture. By a suitable degree of moisture is here understood that degree which corresponds to the natural requirement of any particular species, which it is desired to grow. The more uninterruptedly that degree is maintained throughout the growing season, the more favourable will be the development of the tree. Apart from climate and subsoil, the condition of the soil itself, its depth, porosity, the nature and proportion of its component parts, affect the degree of moisture. The forester can d(j much, either to preserve moisUue in the soil by EFFECT OF SOIL ON FOREST VEGETATION. 37 excluding or reducing the agencies which dissipate it, or, if there is excess of moisture, by accelerating its consumption, or by draining. The absolute quantity of moisture required annually by each species is still under investigation, but experience has shown, that a fresh soil with, as far as practicable, an even and constant degree of moisture suits most of the species enumerated above. For the rest, they may be classified as follows : — Most Dwistiire in the soil demand .- Common alder ; next to this ash, most poplars and willows. Moist soil like : Cembran pine, hornbeam, elm, lime, mountain ash, pedunculate oak. Fresh soil like ; Silver fir, spruce, larch, beech, sessile oak, Norway maple, sycamore, Weymouth pine sweet chestnut. On dry soil thrive : Corsican pine, Scotch pine, Austrian pine, birch, acacia, aspen. 4. A suitable Chemical Co)nposition. Apart from water and gases, the soil consists of mineral and organic substances. These affect the development of the trees partlj^ by providing nourishment and partly by determin- ing the physical properties of the soil. Woody plants take by far the greater portion of their nourishment from the air, more especially carbon, but a certain portion, including the mineral substances, is derived from the soil. Hence it is of importance to ascertain the actual quantities of such substances in the plant. The contents of mineral substances vary in different parts of the tree ; thus wood taken from the stem generally contains less than 1 per cent, of ashes (according to weight), branches and twigs about 2 per cent., bark alone 2 — 3 per cent., and leaves and needles from 4 — 6 per cent. Eber- mayer* gives the following quantities of the more important * Physioloeische Chemie der Pflanzen, Volume I., patre 701. ;is LOCALITY AND FOliKST VIUJETATION , substiinces, wliit-li aii average (•io[> takes from the soil, per acre and year : — Table showing the prixcipai- Mineral Substances taken Annually BY vAiuous Field and Forest Crops from an Acre of Land. Dc-scriptioii of Crop. Total Qn.iiitity of Ashes. KoO. I CaO. MbO. P/),. SOs. SiO.2. live, wheat, barley, oats Leguminous Crops, various Colza .... Clover (hay) Potatoes lieet .... Meadow Hay Tobacco Wine .... Averacre . Croj)s of Trrr.s. moid ,i„(l lea res : Beech, hifrh forest Silver fir spruce ,, Scotch pine ,. Average . Cnipg of TrrcK. wood onhj : Beech, high forest ' . Oak Silvei' fir „ Spruce ., Scetcli ]iine ,, Birch, high forest Average . 11,s. ]8(J 173 1 '.»'.) 308 281 820 294 2U !'.)!> 23.-. 28 44 .52 98 107 164 71 84 lbs. 14 44 39 107 36 36 44 27 41 lbs. '•* 11 14 27 18 24 18 13 1.5 lbs. 21 27 43 36' 32 28 27 16 24 lbs. 4 9 27 11 14 11 11 12 lbs. 100 9 9 9 8 14 107 7.5 78 43 17 28 11 37 194 123 138 52 126 13 16 8 6 S9 62 24 1.5 10 8 12 10 4 4 4 3 2 .56 8 4.5 6 11 62 10 8 3 29 27 24 17 20 13 12 2-7 6 4 2 2 13 18-7 4 9 8 4 3-7 0-9 3 2 1 2 2-3 0-9 1-8 1-3 0-9 1-2 0-3 0-2 0-9 0-6 0-2 0-1 2-7 ' 0-4 v\ 0-4 0-9 19 4 9 2 1-4 0-4 1-6 The (lata of this table justify the following conclusions: — (1.) The substances required by foresttrees are, (i[ualitativel^y, tlie same as those required by field crops. (2.) Beech high forest requires for the production of leaves and wood nearly as much mineral substances as an average field crop ; it requires more lime, but much less of the rarer substances, such as potash and phosphoric acid. (3.) Conifers require smaller quantities, especially Scotch EFFECT OF SOIL ON FOREST VEGETATION. 89 pine, which is satisfied \Yith about one-fourth of those wanted by beech. (4.) For the production of wood alone (excUuhng the leaves) forest trees require much smaller quantities, than field crops. Thus beech takes only one-ninth, Scotch pine about jV^h, and the six species enumerated on an average about J^th of the quantity required by field crops. Of the rarer substances, potash and phosphoric acid, trees take, on an average, only about ij\y^h of the quantity necessary for field crops. (5.) Almost any soil can furnish a sufiicient quantity of mineral substances for the production of a crop of trees, provided the leaf mould (humus) is not removed, and good soils will continue to do so, even if a certain portion of the humus is taken away. If, however, the removal of litter is carried on annually and for a long period, any but really fertile soils are likely to become exhausted, just as lands, on which fields crops are grown, cannot as a rule go on for ever without manuring. (6.) Poor soils, which are not capable of producing a crop of broad leaved trees, may yet be able to yield a fair return if planted with less exacting conifers, especially Scotch pine. The above conclusions agree with the results of practical experience. It has been found, that tbe quantity of wood production is not directly proportionate to the quantity of mineral nourishing substances in the soil. Again, woods thrive equally well on soils of the most different geological origin, while great differences exist in the development of one and the same species if grown on soils of the same geological origin. These phenomena are explained by the great im^Dort- ance of the physical properties of the soil, depth, porosity and a proper degree of moisture. To ensure a favourable condition of the physical properties should, therefore, be the forester's chief aim, and this he can do best by preserving the humus, especially on middling and poor soils. Humus increases the depth of the soil, absorbs from the atmosphere considerable quantities of aqueous vapour, carbon dioxide and ammonia ; 40 LOCALITY AND FOHEST VKOETATION. it is capal)k' of holding ti large (juantity of water, which it gradually gives up to the lower layers of the soil ; it loosens too firm a soil, and gives somewhat more consistency to a soil which hy itself is too porous ; finally it moderates the extremes of cold and heat. The poorer a soil the more important is the preservation of tlie humus, provided it is not acid. 5. Summarji. Summarising all the demands which forest trees make on the soil, it may he said that all species like a soil M-hich is minerally rich, deep, porous, fresh, warm and rich in humus, such as a mild loam with a good layer of humus. Some species find the necessary conditions more on one class of soil than on another ; for instance, oak, beech, ash, elm, maple, and Austrian pine, like a certain quantity of lime in the soil, probably less on account of its chemical composition than of the physical qualities which an admixture of lime produces. ]\rost coniferous trees, on the other hand, are more frequently found on loamy and sandy soils. Though all trees like a good fertile soil, the several species differ considerably as to the minimum of fertility on which they can thrive ; that is to say, some are more exacting in their demands than others. In this respect the following scale is suggested : — Least €.ractiii;i air .- Austrian pine, Scotch pine, Weymouth pine, birch, poplars, tree willows, mountain ash, acacia, mountain pine, white alder. Moderately exactimi are : Spruce, Cembran pine, larch, common alder, lime, osiers, horse chestnut, hazel, hornbeam, Norway maple, Douglas fir. Most cxactinfi are : Silver lir, beech, sweet chestnut, sessile oak, sycamore, ash, elm, and pedunculate oak. It will be observed that the valuable broad-leaved species are, on the whole, more exacting than the soft broad-leaved species and the conifers. P^FFECT OF FOKEST VEGETATION ON THE LOCALITY. 41 Any classification like that given above must, however, be received with some caution ; its object is merely to give a general idea of the subject. In practice deviations occur constantly, according to the local conditions under which the trees grow. Section V. — Effect of Forest Vegetation on the Locality. It has been shown in the previous sections that the condition of the locality governs the growth of forest trees. It is now necessary to consider the effect of forest vegetation on the locality, more especially on two of its factors — humus and moisture. This effect is chiefly produced by the following two agencies : — (1.) The protection which growing woods afford to the soil and adjoining layers of air. (2.) The humus which is formed by the fall of the leaves, branches, twigs, flowers, fruits, etc., and by certain plants growing under the shelter of the trees. In well stocked, or crowded, woods the crowns of the trees form a thick leaf canopy, or complete cover overhead. If the trees are all of the same age and height, the leaf canopy is at a uniform height above the ground, that height being at first small, but increasing with age. In woods of uneven age the cover is of a somewhat different nature ; it consists of groups of crowns at varying distances from the ground. In either case the cover overhead protects the soil and adjoining layers of air against sun and wind ; in even aged woods more against sun, and in uneven aged woods more against wind. Again, the trees shed their leaves, flowers, fruits, and even branchlets, while mosses and other plants, which thrive under the shelter of the leaf canopy, die ; thus a layer of humus on the soil is formed. Finally the roots of the trees penetrate into the soil and keep it together. 42 LOCALITY AND FORKST VKOETATION. The shelter from al)ove, tlic linmns on the soil, and the roots of the trees together prodiu'e certain efTects, wliich may be summarised as follows :— (1.) The temperature of tlic soil and the adjoinhi^ air is lowered during the day and laised during the night ; hence the extremes of temperature are moderated, and the climate rendered more equable. (2.) The mean temperature of the soil and the adjoining air is lowered. The reduction is greatest in summer, next in spring, next in autumn, and it is slight in winter ; it is also greater in the soil than in the adjoining air. (8.) The relative humidity of the air is increased, the eva- poration from the upper layer of the soil reduced, and precipitation may be increased. (4.) A favourable degree of moisture in the upper layer of the soil is maintained.* (5.) Noxious forest weeds are kept in check. (6.) A steady and suitable progress in tlie decomposition of the humus is ensured, whereby the physical qualities of the soil are improved, or at any rate maintained. (7.) An additional supply of organic and nitrogenous matter taken by the plants from the atmosphere and brought into the soil by the falling leaves, flowers, fruits, and twigs, decaying mosses and other plants, is procured. (8.) The soil is protected against the mechanical action of water and air currents. In order to produce these effects in a high degree, it is necessary that the leaf canop}' should be dense, so that it not only keeps out sun and air currents, but also yields a heavy fall of leaves for the production of humus. Only * Iicceiit invest if^iit ions niiulc in Russia and in France seem to indicate, tliat llio level of the i:roiind water in the sod is Inwcied by a itoj) of forest veirctation in luc;ilitic< witli a small or inodei-ate rainfall. EFFECT OF FOREST VEGETATION ON THE LOCALITY. 43 certain species of forest trees possess these two qualifications. During youth most species answer, no doubt, very well ; with advancing age, however, the crowns are not only lifted higher and higher from the ground, but most species thin out considerably. The result is, that the leaf canopy be- comes more and more interrupted and thinner, followed by a crop of noxious weeds, or too rapid decomposition of the humus, accelerated evaporation of the moisture from the upper layer of the soil, and generally a reduction of the fertility of the soil. To prevent such results, the forester must either cut over the woods before the process of thinning- out has proceeded too far, or underplant such woods, or cultivate species which are capable of maintaining a complete cover overhead up to an advanced age. Amongst the timber trees with which this l)Ook deals, beech, silver fir, spruce, and hornbeam, are the species which, above all others, preserve a complete leaf canopy until, or nearly to, maturity. These are shade bearing species. All other species are, with certain modifications, less capable of preserving the factors of the locality ; the greater their light requirement and the thinner their crowns, the smaller is their capacity in this respect. Those least suitable are birch, poplars and acacia ; next willows, larch, most pines (with advancing age), oak, ash, elm, Norway maple, sycamore, and alder. The production of humus from fallen leaves is greater in woods consisting of broad-leaved species than in coniferous woods, because the more important broad-leaved species are deciduous and shed the whole of their foliage every year, while, with the exception of larch, the conifers are evergreen. The silver fir sheds about one-ninth of its foliage annually, spruce about one-seventh, the pines about one-third to one- fourth. The production of humus from fallen leaves is, generally speaking, greatest when the rate of height growth culminates. The accumulation of humus depends greatly on the 44 LOCALITY ANI> FOREST VEGF/FATION. rapidity with whicli the leaves are decomposed, a process which is regulated hj the species, degree of cover overhead, and the cliaracter of the locality. Generally speaking, needles decompose more slowly than leaves. Of needles, those of the larch decompose most quickly, next perhaps those of Weymouth pine, Scotch pine, and Austrian pine, last those of silver fir and spruce. Of leaves, those of ash, alder, hornbeam, lime, and hazel decompose quickly ; more slowly the leaves of oak, birch, and sweet chestnut. The leaves of beech stand perhaps half-way, but as beech woods enjoy a dense shade, their accumulation of humus is much greater than that found in oak or birch woods. On cal- careous and sandy soils, humus decomposes more quickly than on loam and clay soils. It is also more rapid in warm low lands than in cloudy mountain regions. The most suitable, or normal, time for the process may be put at two to three years, when the most favourable results in respect of quantity and quality of humus are produced, A few words about each of the more important species will not be out of place here : — Beech improves the soil in the highest degree, because it has a dense crown and yields a heavy crop of leaves, which decay slowly. Beech woods, if undisturbed, show a thiclcer layer of humus than woods of any other species. TlnniJicam approaches beech in this respect, though it does not equal it. Lime gives good shade and a heavy crop of leaves, but its timber is of such inferior quality that it is rarely planted for economic purposes. Street eheainnt sheds a heavy crop of leaves, but the leaf canopy is comparatively incomplete, admitting too much sun. Oah, ash and iciUoir have too thin a leaf canopy to do justice, generally speaking, to the locality. Silver fir and spruce are capable of preserving a dense cover overhead up to an advanced age. Erert/reen conifers, other than silver la- and spruce, though ASSESSMENT OF THE LOCALITY. 45 they may not possess a dense leaf canopy, are often capable of preserving the fertility of the soil for a certain period, because under their half shade mosses grow, which protect the soil just as well as a thick layer of leaves. When the conifers begin to thin out to some extent, the mosses dis- appear gradually, except in very moist localities ; hence these species should' not by themselves be treated under a high rotation, except in very fertile soils. Of the conifers which are here referred to, Weymouth pine, Austrian pine, Cembran pine, and mountain pine have a fairly dense leaf canopy, and yield a considerable crop of needles, more especially Weymouth pine. Scotch pine has a thinner crown, and a tendency to open out after the age of thirty or forty years, when the moss is liable to disappear and to be replaced by a crop of grass or heather. At the same time, the density of the leaf canopy of this tree differs very consider- ably according to the conditions under which it is grown. The Scotch pine grown in the moist climate of the British Isles gives a much denser cover, than when grown in dry continental climates. Larch provides but a thin leaf canopy in summer, and is leafless in winter. It begins to thin out at an early age ; the moss disappears quickl}', is replaced by grass, and the needles decay rapidly, so that the tree is unfit for preserving the fertility of the soil. The power of preserving the factors of the locality which is peculiar to the several species, governs their adaptability to be raised in pure woods, a subject which will be dealt with further on. Section VI. — Assessment of the Quality of the Locality. It is the duty of the forester to determine, in the case of any particular locality, which species is best adapted for H) LOCAMTV AND FoUKST VK(;KTATI()N. cultivation, so as to realise the objects of the proprietor. In order to attend to this duty successfully, means must be provided by which the niiaJitu, or ii'n'hl ((ijxKit;/, of the locality can be I'eadily ascertained. Various methods have been i)roposed for this purpose, of which the following two will be shortly considered here : — (1.) Assessment according to the severnf fiictors of the locality. (2.) Assessment according to a crop of trees already produced on or near the locality. "Whenever the second method is possible, it should be followed ; only in the absence of a forest crop should the Urst method be adopted. A third method may be mentioned. It has been pro- posed to assess the quality of the locality according to the natural appearance of certain plants, which would depend either on the presence in the soil of certain substances, or on certain other conditions of the soil. Though this holds good to some extent, the method of assessment by itself is without practical value in sylviculture, but it may be used as an auxiliary of the method now to l)e described. 1. AsS('tis)H('nt of' the Localiti/ acconliini to its scrinil Factors. The factors of the locality naturally arrange themselves into two groups, those of the climate and those of the soil and subsoil. As regards climate, it is necessary to ascertain : (a.) The geograpliical position of the locality, that is to say, the latitude, and in some cases, the longitude. (/>.) The local peculiarities of the locality, such as altitude, aspect, slope, surroundings, temperature, moisture in the air, rainfall, (exposure to strong, cold or dry winds, susceptil)ilily to late or early frosts, etc. All these matters have been dealt with in a previous section. ASSESSMENT OF THE LOCALITY. 47 Turning to the soil, the following points, as already indicated, require attention : — («.) The depth of the soil. (/>.) The degree of porosity. (e.) The -degree of moisture peculiar to the soil. {(1.) The chemical composition. A detailed examination of the factors of the soil is a com- pHcated and difficult operation, which it is not intended to describe here. There is, however, a somewhat rough and ready method, which generally suffices for sylvicultural purposes, and which will be shortly indicated. The most convenient way of examining the soil is to dig a hole, if possible in a spot which promises to yield average results. On fairly level ground the spot should be selected on an average part of the area, that is to say, neither in any small depression nor on any slight elevation which may exist. In hilly or mountainous localities, separate holes must be dug on the ridge, the slope and at the bottom of the valley. The depth of the hole must be at least equal to the depth to which the roots ordinarily penetrate, that is to say, 8 to 4 feet. Where rock is met at a smaller depth than this, its stratification and general composition should be ascertained, as well as its effect upon the regulation of moisture and the stability of the trees. One side of the hole, at any rate, should be perpendicular, so that the thickness of the successive layers of the soil can be measured, in so far as they are indicated by different colour, different degree of cohesion, and other outward signs. The depth to which the soil is coloured dark by humus should be specially noted. This operation will show, whether the soil is sufficiently deep to admit of a proper spreading of the roots, and if not, the examination of the subsoil will indicate, how far the latter can make up for the shallowness of the surface soil. The same operation will indicate, what effect the depth and nature of the soil have on the degree of moisture. Next •J8 LOCALITY AND FOHKST VLffKTATlON. the degree of division, or the nature of the grain of the soil, must be ascertained. This can be done by shaking a sam- ple, if necessary of each successive layer, with about three times its volume of water in a graduated tube, until all parts are thoroughly separated ; the tube is then placed in a vertical position and watched. As coarse grains settle more quickly than fine grains, it follows that the time occupied compared with the thickness of the deposit indicates the degree of division of the particles. A high degree of division indicates a stiff soil, the presence of coarse grains the reverse, and thus an idea can be formed of the degree of porosity. If necessary, the capacity to absorb water, to attract it from the subsoil, to retain it, and the hygroscopicity of the soil can be ascertained by special experiments, l)ut in practical sylviculture they are rarely called for. The exact composition of the soil can only be ascertained by means of a chemical analysis. In practice the forester can easily acquire the faculty of distinguishing in a rough and ready manner between the several constituents. He recognises: — Clay by a high degree of cohesion, a fatty feeling, active absorption of water while emitting a clayey smell, slow disintegration in water, slow drying followed by cracking, frequently a grey colour, etc. ; loam by a lesser degree of cohesion than in the case of clay, rougher feeling, quicker disintegration in water, and generally a more reddish colour ; Utuc by active effervescence if treated with an acid, porosity, light whitish to greyish-white colour, which is, how- ever, frequently turned red by iron, a rough but line grained feeling, etc. ; sand by very slight cohesion, grinding between the teeth, or hard grainy feeling, immediate disintegration in water and rapid settling down in it, a light, glossy, shiny, yellowish-white colour, often converted into red by iron, into white by lime, into black by humus ; humns by its porosity and light weight, peculiar smell like that of fresh garden earth, rapid disintegration in water, wliicb remains dark ASSESSMENT OF THE LOCALITY. 49 coloured for a long time, blackish colour which disappears on roasting ; iron by red colouring, etc. In order to recognise more easily the principal constituents of a soil and their proportion, a sample may be mixed in a glass tube with about twice its volume of water, well stirred until completely dissolved, and then allowed to settle. At the bottom of the glass tube the following deposits will be observed, beginning with the low^est : — First : The rougher grains of sand. Second : The finer grains of sand. Third: Lime, chalk and the coarser clay. Fourtli : The finer clay and particles of humus. The thickness of the layers indicates the proportion of each substance. In spite of the most persevering attempts, experience has shown that the assessment of the locality in the manner indicated above is always subject to grave errors, because the various factors may compensate each other, replace one another, or may be altogether unassessable. To make matters worse, the factors are rarely the same over exten- sive areas, but change from one spot to another. On the whole, the method which has just been indicated can only serve as a make- shift when no better means of assessment are available, or as a help in the application of the method now to be described. 2. Assessment oj the Loecdity according to a Crop of Trees prodiiccd hy it. When a locality has already produced a crop of- trees, it may be assumed that, unless extraordinary events or irregu- lar treatment have interfered with the development of the trees, the effects of all its factors have found due expression in such crop, which is therefore the best guide for the as- sessment of the quality, or yield capacity, of the locality. If, for instance, an acre of ground has produced a total s. t; 50 LOCALITY AND FOREST VEGETATION. quantity of 5,000 cubic feet of wood in the course of 100 years, the quality, or annual yield capacity, is represented by ^*^^^=oO cubic feet, in other words, by the mean annual production. The applicability of this method depends principally on the following three conditions: — (a.) That the existing wood has grown up under normal conditions ; in other words, that no extraordinary dis- turbing events have occurred which affected the health and development of the crop, as, for instance, damage by cattle or deer, insects, fire, theft, removal of litter, faulty treatment, etc. (h.) That the factors of the locality have not undergone any decided change, either for the better or worse, during the production of the crop ; for instance, the stock of humus or the degree of moisture may have been affected by external interference. {('.) That the existing crop is of a sufficient age to make sure that the factors of the locality have found a thorough expression in the same, since a wood may thrive well up to a certain age and then fall oft' con- siderably. Whenever these conditions exist to a fair extent, the method of assessment is the best which is at the forester's disposal ; and in its application he need not restrict him- self to a crop actually growing on the area, but may be guided by one growing on a neighbouring piece of land, provided the general conditions are about the same in both cases. A great quantity of data bearing on the j'ield capacity of land under forest has, in the course of time, been collected and brought together in so-called " Yield Tables,'' that is to say, tables which indicate the yield which an acre of land may reasonably be expected to give according to whether it belongs to one or the other quality. The details regarding yield tables will be found in ASSESSMENT OF THE LOCALITY. 51 Volume III. of this Manual, following data may be given By ^Yay of illustration the Total Production of Timber and Firewood in the course of One Hundred Years, in solid Cubic Feet per Acre. Species of Tree. Total Production on the I.,oi-Be.st Quality. II., or Medium III. , or Lowest Quality. Quality. Silver fir . . . 23,900 16,500 10,700 Spruce .... 22,200 1-t.OOO 7,200 ) Datad erived r.eech .... L->,200 9,300 4,700 ; from numerous Scotch pine . 13,500 8,500 3.500 and reliable Oak grown on alluvial measurements. soil .... 12,700 9,400 6,200 Larch .... 12.100 6.800 l,S0O ) Data somewhat Alder .... !M00 5,400 1,700 [ less J reliable. Birch .... 7,900 4,300 1,100 The quantities given for the first quality are the highest which can be produced, and they are comparable for the several species ; the same may fairly be said regarding the figures given for the second, or medium, quality. The quan- tities given for the third, or lowest, quality are less com- parable, because the lowest limit suitable for the several species differs considerably. Of our more common forest trees, silver fir produces the greatest quantities, and spruce comes near it. As regards oak it should be noted, that the figures refer to woods grown on alluvial soil only ; there are as yet no data available for oak grown on other lands. Taking Scotch pine as an example, it may be said, that, if a localit}^ stocked with it has produced 13,500 cubic feet of woody matter in the course of 100 j^ears, that locality is of the first, or best, quality or yield capacity ; if it has produced 8,500 cubic feet, it is of a medium quality ; and if the pro- duction amounts to only 3,500 cubic feet, the quality is of the lowest, on which that species is ordinarily grown. The quantities given above include all thinnings taken out of the woods in the course of the 100 years. E 2 52 CHAPTER IT. DEVELOPMENT OF FOREST TREES, In dealing with the shape and development of forest trees, it is assumed that the student has already acquired a botanical knowledge of the several species, so that here only their sylvi- cultural characteristics need be described, more especially the shape peculiar to each species, the height, diameter and volume growth, lease of life, and reproductive power. 1. Shape. Different species of trees naturally develop different shapes. Some species, like spruce, silver fir and larch, have a decided tendency to form a strong stem in preference to the develop- ment of the crown. Others, like oak, lime and sweet chestnut, develop their crown in preference to the stem. Some species are frequently forked, as ash, false acacia, and also elm. Cembran pine often shows a candelabra-like shape, especially in stony localities. The actual shape depends, however, on a variety of influences, amongst which the following may be mentioned : — a. GroiriiKj Sp(i / A Y^ r/ / y\ f A (A / (y^ y / / ■y^:^ ^ ^ ■M Silvor Fir. Spruce. 10 L'O 40 '.0 00 70 SO '.10 1110 110 I'JO AGE, I\ YEARS. Fig-. 2.— Diap-am illustrating the Diameter Growth of Silver Fir, Spruce, Beech, and Scotch Pine, on Localities of the First Quality. increment, a free position increases it ; hence height growth and diameter growth demand frequently opposite con- ditions. It is the business of the forester to give the most profitable growing space ; in other words, to give to the individual trees from time to time sufficient room to en- courage diameter growth, without endangering the progress of the height growth. The effects of a great surface of foliage and unimpeded enjoyment of light are very remarkable, when licallhy trees, VOLUME GROWTH. 59 which have been raised in a crowded wood, are gradually given more growing space. Such an opening out can, provided the period of height growth has not come to an end, produce a revival of the diameter increment, after its maximum has been passed, due to an increased leaf surface, or to a greater intensity of action, even if the leaf canopy is not materially extended. This revival of diameter growth generally lasts for a number of years, differing according to species and quality of locality, when it gradually dies away again. Nor does a tree profit by an excessively large leaf- surface, because there is a limit, beyond which a tree cannot assimilate and convert into wood the nourishing elements available to it. Where both great height and diameter growth are wanted, it is best to keep the wood crowded during youth, and to give only a moderate growing space to each tree until towards the end of the principal height growth, when the growing space of each remaining tree should be gradually increased, so as to develop more extended crowns and greater diameter growth. This is only possible while height growth is still going on ; once that has stopped, the thinning out will not be followed by any appreciable extension of the crowns, which can only be produced by transferring to it the energy of height growth. The possibility of such a transfer is longest preserved in silver fir, spruce, oak, and beech. 4. Volume Growth. The increase in volume depends on both height and diameter growth, and that method of treatment which promotes each in due propoi'tion, must ultimately yield the largest volume ; in other words, woods should be neither too crowded, nor too open. In the one case thin tall trees, and in the other short thick trees would be produced. The most favourable density of the crop can only be ascertained by accurate statistics. General experience has shown that the greatest volume is ultimately obtained, if the woods are 60 DEVELOPMENT OF FOREST TREES. moderately heavily thinned from their youth onward, hut this interferes often seriously with the ([uality of the timber. Ajiart from these general considerations, a great difference exists in the vohime produced by the several species when grown in regular woods ; in this respect some of the more important kinds may, according to the latest investigation, be l-'ir. •J4,000 1 — / •J-J,000 / / y~ -'0,000 {^ y "A / ^ ir.ooo // f >2 / 1 y ^ ]-.',0pruce. Silver Fir. Uif.-h and Scotch Pine. iO CO 70 80 AGE, IN' YEARS. 100 110 120 Fig. 4.— Diagram illustrating the Numher of Trees per Acre at Various Ages, and on "" Localities of the First Quality, of Spruce, Silver Fir, Beech, and Scotch Pine. by itself govern the increment produced per acre, because the latter is represented by the increment per tree multiplied by the number of trees per acre. For instance, if an acre of ground can hold 100 mature silver firs, each of which has a volume of 100 cubic feet, the total volume per acre will be 62 DEVELOPMENT OF FOREST TREES. 10,000 cubic feet ; if an acre can hold 50 mature oak trees, each \vith a vohime of 150 cuhic feet, the total volume per acre will be only 7,500 cubic feet, or 2,500 cubic feet less than in the case of silver lir. The number of trees which find room on an acre of ground depends chiefly on (a.) The light requirement of the species. {h.) The tendency of the species to develop the crown in preference to the stem. (r.) The quality of the locality. Hence, an acre stocked w4th the light demanding birch, ash, or spreading oak, contains a smaller number of trees and a smaller volume than an acre stocked with beech. Again, larch, and Scotch pine woods contain fewer trees and a smaller volume per acre than silver fir and spruce woods. The number of trees per acre on a fertile soil is consideral)ly smaller than on an inferior soil. Full details on this question will be found in Volume III. of this Manual. In the meantime the accompanying diagram (p. 61) will give a general idea of the number of trees found on localities of the first quality in the case of spruce, silver fir, beech, and Scotch pine. 5. Iniration <>/ Li/r. A great dift'erence exists in the age which the various species attain ultimately. If grown under conditions which are in harmony with their requirements, the yew lives for more than 1,000 years, the oak comes often near that age, if it does not exceed it ; lime, elm and sweet chestnut reach and surpass an age of 500 years; beech reaches a similar age under favourable circumstances, but ordinarily both beech and silver fir die before that age. A limit of 300 years may be assigned, to ash, maple, sycamore, spruce, larch, Scotch pine and hornbeam ; while aspen, birch, alder and willow- live, under ordinary conditions, little beyond 100 years. In forestry the trees are, as a rule, cut over Iwig before DURATION OF LIFE. 63 they have reached the natural lioiit of their life. Never- theless many cases occur, ^Yhere trees have been grown under conditions which are not quite in harmony with their requirements, so that they die, or at any rate fall off in health and growth long before they would, in the ordinary course, be cut over ; hence it is of importance to consider the conditions under w'hich the growth continues to be healthy to an advanced age. In the first place, the nourishing organs, crown and roots, must be able to develop normally in accordance with the requirements of the tree at the different periods of life ; in other words, they must be given at all times the required growing space, without, however, checking their height growth or interrupting the cover overhead for a lengthy period of time. Unless a tree is provided with a sufficient quantity of organs, it will not be able to overcome successfully internal and external damage which endangers its life. The power of resistance in this respect differs considerably in the various species. It is great in oak, hornbeam, lime, willow, elm, yew, and Cembran pine, but small in alder, Norway maple, sycamore, beech, spruce. The second condition of longevity is, that the locality should offer to the tree all it requires for a proper deve- lopment. On the whole it may be assumed that, where a tree is indigenous, it finds all it requires (though this is not without exceptions). Localities wdth different factors are liable to be unsuited to the species, either from offering too little or too much in respect of temperature and moisture, or insufficient nutriment and depth in the soil, etc. Either case may be injurious to the development of the tree, and especially to the quality of the timber produced. For in- stance, spruce is naturally fond of a cool climate ; by trans- ferring it to the dry and warm air of the low lands, it generally grows much more quickly, but does not jdeld the same quality of timber, is shorter lived, and subject to more dangers, than in its mountain home. 64 DEVELOPMENT OF FOREST TREES. Trees raised in fully stocked compact woods do not live as long as when <,m(j\v]i in the open. Moreover, in that case various other important considerations must he taken into account. After having weighed these, the forester decides on the age limit which is most likelj' to realise the objects of management. What the objects of management are, has been indicated in the Introduction to this volume. They govern the deter- mination of the rotation, or the time which elapses between the formation and final cutting over of a wood. Whatever motives may influence the determination of the rotation from a sylvicultural point of view, it should be so fixed under the method of natural regeneration as to admit of a proper regeneration of the wood, whether by seed or coppice shoots ; in other words, the wood must l^e cut over while the repro- ductive power of the species is in an active condition. For further details regarding the determination of the rotation the reader is referred to Volume III. 0. llcproductin' Poircr. The tendency to reproduce the species manifests itself throughout nature ; in fact the energy devoted to reproduc- tion is frequently stronger than that bestowed upon the preservation of life. Forest trees, in obedience to this law, produce seed during a considerable part of their life, and in large quantities. In sylviculture, the reproduction of trees and woods is effected in two distinct ways, namely : — {(I.) From seed. {}).) From shoots which spring from the stool or the roots, followed, in many cases, by the division of the mother plant. a. Iivpr/" 30 — 40 yeitis: Scotch pine, Austrian pine, Weymouth pine, larch, Norway maple, common alder, lime, horse chestnut. .4^ tJte aijc of 40 — 50 ijcarn : Hornbeam, elm, ash, sycamore. At the age n)(hicti<)ii in inaiiitniiii'd hci/oiiil an acjc of 40 i/fars in the cfoif of: Oak, sweet chestnut, hornbeam, elm, alder. It ccasrs at an rarliey afjc in : ]jeech, birch, Norway maple, sycamore, ash. The conifers have no power of reproduction of this class worth mentioning. Larch shows best amongst conifers, and the three needled pines next. Some species produce only stool shoots, others only root suckers, and others again both : — Principalbj stool shoots : Oak, hazel, hornbeam, beech, elm, sweet chestnut, hme, black poplar, alder, ash, sycamore, maple, willow, birch. Princijyalhj root sachcrs : Aspen, white alder, false acacia, white poplar, and willows. The age to which stools live differs considerably, according to species and locality. "While the stools of oak and hornbeam last for centuries, those of beech are comparatively short lived. The osiers in the Thames valley, if coppiced annually, are said to last only about 10 years. 69 CHAPTER III. CHARACTER AND COMPOSITION OF WOODS. In sylviculture trees are only in exceptional cases reared in free positions ; as a general rule they are grown in consider- able masses, which' form more or less crowded woods. Such woods may be composed of one species only, or they may contain a mixture of two or more species ; in the former case they are called j^ure woods, and in the latter mixed icoods. Naturally pure woods occur only under certain conditions, as, for instance, when the factors of the locality suit only one particular species, or when the vitality and energy of one species has gradually ousted all others. Species which appear naturally in pure woods are called gregarious. The bulk of the pure woods, which exist at present in Europe, are the result of artificial interference. By far the greater number of natural woods are mixed. Section I. — Puke Woods. Practically, woods are rarely quite pure, because in most cases specimens of other species, which it was not intended to rear, make their appearance uninvited. As long as such an admixture is slight, accidental and not taken into account by the management, the character of the pure wood may be said to be preserved. The principal advantage of pure over mixed woods is, that they are easier to manage, because the requirements of only one species have to be considered. On the other hand, they have often disadvantages as compared with mixed woods, which will be dealt with in section II. 70 CHARACTKH AND COMPOSITION OF WOODS. The litness of a s[)ecies to l)t' laisfd in piiie woods depeiuls on its capacity to preserve, or even improve, the factors of the locality, in other words, whether the species preserves a complete leaf canopy to an advanced age, and secures the accumulation of a sutticient layer of humus. As indicated in section IV. of chapter I., beech, silver tir and spruce act most beneficially in this respect, and next to these some of the pines. Apart from them, several others are frequently grown in pure woods, such as oak. larch, Scotch pine, birch, and willows, on account of their great utility. Of the remaining, or so-called dcpnuh itt species, few are found in pure woods, and then only under special circum- stances ; for instance, hornbeam replaces beech in frost localities, Cembran pine and mountain pine occur at high elevations, maritime pine on dunes near the seashore, alder in wet localities, sweet chestnut as coppice for pit wood, vine stakes, etc. On the whole it may be said, that dependent species may be grown as pure Avoods in the following cases : — (l.^i If the factors of the locality are such that an imperfect cover and want of humus do not materially injure them ; as in deep fertile soils, which enjoy an ample and well distri- buted rainfall, or which are kept moist by ground water or irrigation. (2.) If the woods are treated under a short rotation, so that they are cut over before any excessive interruption of the leaf canopy has set in ; or if it is intended to underplant them, when the}' connnence to open out, as in the case of oak, larch, and Scotch i)ine. (8.) If the object is to utilise localities which are only lit for certain species ; for instance, alder and willow on wet soils, hornbeam in frost localities, etc. (4.) If only one species linds a ready market, or is reciuired for a ^|icciiil [)iM'[)ose. I'i.xcept in such cases, all ilej)eiuU:iil species should he I'aised in mixed woods. ADVANTAGEH OF MIXED WOODS. 71 Section II. — Mixed Woods. A mixed wood may be so arranged that every tree of one species alternates with a tree of another species, in which case the mixture is called one hy single trees. Or a group of trees of one species may alternate with a group of trees of another species, called a mixture hy groups ; in the latter case the groups must not be of such extent, that each acquires the character of a pure wood.- Mixtures may also be arranged in alternate lines or strips. Mixed woods may be : — (a.) Permanent or temporary. (b.) Even aged or uneven aged. Temporary mixtures are ordinarily called for in the following cases : — (1.) When the intention is to obtain an early return, by the removal of one of the species, which should in that case be of rapid growth. (2.) When a tender species has to be protected (nursed) during early youth against frost or drought, as beech and silver fir, and to a less degree oak. In this case a hardy and fast growing species, such as Scotch pine, larch, birch, is raised either simultaneously or beforehand, and removed when the tender species requires no further protection. Near the sea coast, it is generally necessary to grow first very hardy trees, so as to establish sufficient shelter ; more valuable trees may afterwards be introduced between the nurses. (3.) When both the above objects are combined. Permanent mixtures are established, because they are con- sidered to have advantages over pure woods. 1. Advantages of Mixed Woods, (a.) Mixed woods admit of a more complete utilisation of the factors of the locality, and consequently they produce a larger quantity of wood, if the mixture is suitably arranged. Each 72 CHARACTER AND COMPOSITION OF WOODS. spot can l)e stocked witli tlie species which is best iulapted to the factors of the locaUty ; lience iiici"eased production follows. {!).) Unless very extensive areas are availal>le, only mixed woods enable the forester to meet the various demands of the market. In the case of pure woods, and if a regular annual yield of each of several species is expected, a complete series of age gradations is required for each species, which, in the case of a limited area, would lead" to small annual coupes. For instance, if the intention is to grow five species on an area of 500 acres under a rotation of 100 years, each cutting w^ould extend, in the case of pure woods, over one acre, while in the case of a mixed wood, the annual cutting may be live acres in one block. It has already been stated, that only a few species are lit to be grown in pure woods. At the same time many of the other species yield a very superior quality of timber, or valuable minor produce. All these would more or less disappear under the system of pure woods, or at any rate they would not thrive so well and would not develop equally line boles, as if grown in mixed woods. Large sized timber of many light demanding species can only be produced by mixing them with shade bearing, and consequently soil preserving species. (r.) Many species suffer less from exteriuxl injurious in- fluences, such as wind, fire, frost, snow, insects, fungi, if raised in mixture with other more hardy species. — A shallow rooted species had best be grown mixed with a deep rooted species. — Conifers are less exposed to damage by fire or snow, if mixed with broad-leaved species. — Insects are less dangerous in mixed woods, as they generally attack only one of several species ; moreover birds, the great insect destroyers, are more numerous where broad- leaved trees grow, than in pure coniferous woods. — Damage by fungi to conifers is also considerably less if they are mixed with broad-leaved species. — A hardy species mixed with a tender species protects it against frost, drouglit and injurious air currents. DISADVANTAGES OF MIXED WOODS. 73 {(1.) Mistakes made in the selection of species can be more easily rectified in mixed, than in pure woods. The suitability of a locality for a certain species is not always apparent at the outset ; in the case of mixed woods the species which is least suitable can be removed at the time of thinning, {('.) For the above reasons, mixed woods will, in many cases, yield better returns than pure woods. ( /".) Finally, mixed woods increase the artistic beauty of a countr3\ 2. Disadvantages of Mixed JVoods. It is frequently described as a disadvantage of mixed woods, that their natural regeneration is more difficult, than that of pure woods. No doubt, different species require different con- ditions, if natural regeneration is to be successful. More especially the cover of the mother or shelter trees must be more open where a light demanding species is to be regener- ated, than in the case of a shade bearing tender species. The shelter, for instance, which suits the beech, would probably kill young oak seedlings. Again, certain species, such as spruce, produce so much seed, spring up so easily, and would take possession of so much ground, that other species, like silver fir and beech, would have little chance of coming up in sufficient numbers. In the Black Forest, silver fir has fre- quently to be helped against the beech. These objections are undeniable, but they are, after all, not of such importance as might appear at first sight. In the first place, the mother trees can be so selected, that one species is favoured against the others. Secondly, the surplus regeneration of any one species can be removed in the first thinnings. Thirdl}', the species can be arranged in small groups. Fourthly and chiefly, the best procedure is, to regenerate naturally with special reference to one species, and to introduce the others (as far as necessary) artificially. In the Black Forest, for instance, silver fir is favoured in the regeneration, and spruce is, if necessary, afterwards planted in. In this manner the forester can produce the desired proportion of the several 74 CHARACTER AND COMI'OSITION OF WOODS. species with almost miithemalicKl accuracy. On the whole, mixed woods otier substantial advantages over pure woods. At the same time it must not be forgotten, that the treatment of pure woods is much simpler, than that of mixed woods. Hence, the former may be preferable, whenever really competent managers are not available. 8. Hull's for the. Foniuttii))! of Mixed Woods. The advantages of mixed woods, which have been detailed above, will only be realised under certain conditions, the more important of which are tbe following : — {a.) The locality must be, a priori, suitable for the favour- able development of each of the species in the mixture. {h.) The mixture must be of such a nature, that the factors of the locality do not suffer ; they must, whenever possible be improved. This will only be the case if the principal, or more numerous, species is soil improving. As indicated above, exceptions occur when woods are treated under a short rotation, or when the quality of the locality is such, that it does not require to be assisted by the improving action of the trees growing on it. (c.) The mixture must be so arranged that one species does not oust the others, and establishes a pure wood. The exces- sive development of one species may be S. thrives best on loose, warm, deep soils with a f^ood measure of water in the subsoil ; spruce recjuires moisture near tlie surface, and it is satisfied with a moderately deep soil. Oak requires much light, heat and space : the demands of spruce are more moderate in these respects. Oak is inclined to develop large branches; spruce grows nioic in lieiglit. Never- theless, artificial mixtures of the two species are advocated by some foresters. Oak grows faster than spruce during youth ; later on spruce passes the oak, and the latter has no chance if mixed by single trees in even aged woods. It is necessary to place the oak in ^loups, and even then it does not always develop satisfactorily. The best arrangement is to plant oak pure and to bring in the spruce when the oak begins to thin out. It has, however, been noticed that the oak becomes stag headed when underplanted with spruce, a phenomenon which is l)y some foresters believed to be due to the great consump- tion of water by the spruce ; hence the mixture is only admissible under favourable conditions, oi- when the spruce is cut out at a comparatively early age, before it has liad time to injure the oak. (}<(k and s'lInT I'lr. — This is a better mixture than that of oak and spruce, as the two species resemble each other more in tlieir demands on the locality. Oak requires a start, or it will 1)6 passed at about middle age and suppressed by silver fir. The best plan is to plant oak pure, and to bring in silver fir when the former begins to thin out. Oak and Jx'ccli. — This is a most suitiiblc niixtui'e, as the two species stand sufliciently near each other in re8i)ect of locality and shape ; moreover, they are found natui-aiiy together. The beech has l)een called the oak's nurse. The oak finds in the mixture all the advantages of a permanent complete shading of the ground, accompanied by a heavy fall of leaves, a thick layer of humus, and freslnujss of the soil; it tliiis iUtains great height and a clear bole of considerable length. Tlu! oak requires to have its head free throughout life. It trrows more (luicklv than beech if the climate a)id soil suit SHADE BEARING WITH LIGHT DEMANDING SPECIES. 83 it thoroughly in respect of moisture and depth. In such locahties the mixture may be arranged by single trees. In the majority of cases, however, the oak is left behind by the beech, and then the former, in single trees, is lost ; hence the mixture must be arranged by groups, or all threatening beeches cut back or removed ; or the oak is given a start, the beech being brought in when the oak commences to thin out, that is to say, between the 80th and 50th year, according to circumstances. Oak and hoDihi'um. — This mixture may be desirable in localities which do not suit the beech, as for instance in frost localities, or moist deep sandy soils of the low lands. The oak grows quickly enough to hold its own against horn- beam. In this mixture the hornbeam is frequently treated as coppice. (4.) Nortcay maple and sycamore in mixtare wWi more sliade hearing species. — Such mixtures require a fresh, deep and fertile soil. During early youth both maple and sycamore grow more quickly than spruce, silver fir, and beech, but later on they are passed by the shade bearing species. Hence, it is necessary to place the maple and sycamore in groups, or to give them a start in age; by far the best mixture is that with beech. (5.) Aslt in mixture witlt sJuide bearim/ species. — The best mixture is ash and beech ; not so good is that of ash and silver fir, and still less that of ash and spruce. Ash, like the maples, grows first more quickly than beech, but is generally passed by the latter later on, hence it should be placed in groups in the moister parts of the locality. Where ash occurs pure, it should be underplanted with beech or hornbeam long before its height growth has been completed. (6.) Kim in mixture with sliade hearing species. — Elm does best in mixture with beech, or perhaps hornbeam. The mixture of elm with spruce and silver fir is less desirable. Elm requires a locality with sufficient warmth, or else it will not develop into a large-sized tree ; it also requires a deep 81 chakacti:r and composition of woods. fertile soil. Elm grows at first more quickly than beech, but afterwards it is liable to be passed, hence it must be placed in groups, or given a start. The groups of elm should subse- quently l)e underplanted with beech. (7.) liiirli in iiii.vtiiii' iritli s]iav the removal of single trees or small groups selected here and there over the ^Yhole area, and this process goes on through- out the whole length of the rotation, so that practically no part of the whole forest is ever at rest. All age classes, from one year old to the oldest, are constantly represented, by single trees or small groups, over the whole area, and, theo- retically, the work of selecting trees for cutting extends at all times over the whole extent of the forest. In practice, how- ever, the forest is divided into a number of blocks, which are gone over in turn, so that cutting returns to the same part only after the lapse of several years. //. Kxternal iJanyen^. Views differ somewhat regarding the extent to which selec- tion forests are exposed to external dangers, as compared with the two previously mentioned slielter-wood systems. In the absence of exact comparative observations it may be stated, that in respect of drought the selection system acts very favourably, because only very small plots are, at one time, exposed to sun and air currents. The same may be said in the majority of cases, as regards frost. Nothing definite can be said in respect of damage by insects. As regards damage by wind, snow, etc., views differ. '■. Prodwlioii of Wdod. Here again actual comparative observations are not avail- able. It has by no means been proved that less wood per acre and per annum is produced under this than under either of the two previous systems. Young growth, no doubt, develops slowly, as it is much interfered with by the adjoin- ing older trees, but this may be compensated for by a more active development, when the trees have secured the full THE COPPICE HYSTEM. 97 enjoyment of light, especially during the more advanced period of life. There can, however, be no doubt, that less clean and shorter boles are produced under the selection than under the compartment system, though the former is specially suited for the production of large sized timber, as each tree can be left in the forest until it has reached the desired dimensions. d. Effect upon the Factors of the Localitij. The system secures an almost absolutely equal degree of protection of the soil throughout the rotation, more especially as regards the preservation of an even degree of moisture, which must act beneficially upon production. Protection is given not only from above, but the uniform mixture of old and young trees also secures lateral shelter. On sloping ground rain water is more effectively retained under this than under any other system ; avalanches also, the carrying away of fine earth, landslips, etc., are prevented ; hence protection forests situated in mountains are usually worked under this system. 5. The Coppice System, a. Orkjin and Gharctcter. Most broad-leaved species have the faculty of reproducing themselves by shoots, which spring either from the roots, stool, or stem. After severing the whole, or part, of the stem above ground, the roots and stool develop shoots, which grow up into poles, and, under favourable conditions, into trees, thus producing a new generation. This process of regeneration can, as a rule, be repeated as long as the stool and roots continue to live. When the trees are cut over close to the ground, simple or ordinary coppice is produced, the shoots starting from a point which is close to, or in, the ground. Generally, several shoots spring from the same stool, and these stand in clumps, and s. U 98 THK sYj,Yicri/rri{AL svstkms. can easily he distinguislied from seedling trees. On well stocked areas a complete cover is established earlier under this system than in seedling forests, as the shoots develop very rapidly during the first few years. A\'lirL'ricrs. wliicli is best iidapted to any special set f)f conditions. Tliey may be bi-onglit under the following headings: — (1.) Suitability of the system to the selected species. (2.) The permanent preservation or even improvement of the factors of the locality. (3.) Protection against external dangers. (4.) Safety and simplicity of the method of regeneration. (5.) Quantity and quality of the produce. (6.) Intensity of management. (7.) Existence or absence of forest riglits. 1. SiiitaJiilif// (i/ fht' Si/steiit to the si'Icctctl SjiccieH. This is a consideration of the first importance in all cases, where it is desired to grow a particular species. In the first place, coniferous species cannot be treated as coppice woods ; while several broad-leaved species, such as beech and birch, possess only a moderate reproductive power by shoots. In all such cases only the high forest systems are indicated ; beech and birch at any rate should not be grown in pure coppice woods. Again, light demanding species with thin crowns are but badly suited for ordinary simple high forest ; they should be raised as standards in coppice with standards, or in two- storied high forest, or with a coppice underwood, or in mixture with shade bearing species. Such species are also difHcult to raise under shelter-woods. On the other hand, tender shade bearers like beech and silver fir are better adapted to the shelter- wood systems than to the clear cutting system. Lastly, whenever a system involves two crops of uneven age on the same area, the overwood must consist of a thin crowned, that is to say, light demanding species, and the underwood of a dense crowned or shade bearing species. 2. I'l-ciniydioii <>/ Oir i'artor^i of thr Loralit//. On general economic principles, forests should be worked and managed for a sustained yield, and not for a temporary CHOICE OF SYSTEM. 109 high return ; hence it is necessary to select a system under which the factors of the locahty are at least maintained, and if possible improved. In the case of exceptionally good localities with a rich fresh soil and a favourable state of moisture and temperature of the air, any system can be adopted which answers to the other requirements of the case. On all localities of only middling quality, and still more so on poor localities, the first considera- tion must be the preservation of the factors of the locality, or else a steady deterioration will set in, which may end in complete sterility. In such cases clear cuttings must be avoided as much as possible,'and every effort made to keep the area permanently stocked with a crop of trees ; in other words, to regenerate under shelter-woods, so as to lead the old crop gradually over into a new crop. Unless this precaution is taken, the degree of moisture in the soil undergoes violent changes, which act most injuriously on production. The systems best adapted in such cases are the shelter-wood selec- tion system, the other shelter- wood systems which produce an uneven aged young wood, the shelter- wood compartment system, and coppice with standards. 3. Protection against external Daiajers. It should be the object of a good management to produce healthy woods, which are capable of resisting successfully the dangers to which they are exposed during life. Though species and method of regeneration are of principal importance in this respect, the system is also of some account. Where the object is to counteract the eroding effects of water running down sloping ground, to prevent the occurrence of landslips, avalanches, or devastation through shifting sand, woods of uneven age must be the rule, such as are produced under the shelter-wood selection system, the group system, etc. Whether uneven aged woods suffer less from wind, snow and ice than even aged woods is as yet an open question. In respect of frost, drought and insects, the clear cutting IKl THE SYLVICUI/rrifAL SYSTEMS. system yields the worst results, the shelter- wood compartment system comes next, and then the systems which produce uneven aged woods, the shelter- wood selection system being best of all. On the whole, localities dill'er nuich ; some larely or never suffer from storms, snow, etc., while others do so every year. Such peculiarities must be takeri into account in selecting the system. 4. Sal'ct/i (Old Siiiijilicitj/ ill' till' Mcllniil nj' l!.) On less fertile soils, which necessitate a careful husbanding of the factors of production, in the case of some of the species being light demanding, or under a high rotation, the systems of uneven aged woods are desirable. The former produce principally long and clean timber, the latter greater girth. In many cases the objects of management favour the pro- duction of minor produce, and the system must be selected accordingly. Where tanning bark of oak is wanted, the system of coppice is in its place. Osier beds require to be planted in cleared land. The growth of held crops also is only practicable under the system of clear cutthig ; at the outside, only a few standards may be left on the ground. Where grass and grazing is wanted, the woods should be even aged, or else the cattle will damage the young trees, etc. (j. Iittcnsity of Manaiiement. The more valuable the returns of a forest are, the more intense, or careful and detailed, should be the system of management. The capital invested in a forest differs considerably under different systems, it being composed of the value of the land plus the value of the growing stock, apart from buildings, etc., which would be required under any system. Hence, high forest requires a much larger capital than coppice, and often yields a suialler interest on the invested capital than the latter. 112 THK SVLVU'l J/rri{AL SVSTK.MS. Artificial regeneration requires a perioilical outlay of cash for sowing and planting, while natural regeneration can he etiected without such outlay, though it may involve a con- siderable loss of time. The transport of the material is considerably cheaper in even aged woods than in uneven aged woods, because in the former case the operations are more concentrated. The same holds good as regards supervision. The shelter-wood systems require more skilled labour than the clear cutting systems. They also make much greater demands on the intelligence and industry of tlie manager, because they require higher skill and more constant sujjcr- vision. 7. Existence or Absence of llojJits. In many cases the existence of rights necessitates the selection of a particular system. For instance, where large timber has to be provided to right-holders the coppice system would be inadmissible. 8. !Suin)narij. Every sylvicultural system has its advantages and dis- advantages, and it is necessary to ascertain in every special case, whether the balance of tha two tends towards the one or other system. From a si/lcienlturcil point oj view, the first point for consideratitm is the general suitability of the system, and next the continued preservation and, if possible, improve- ment of the factors of the locality ; temporary, or immediate, financial considerations should only prevail in so far as they do not interfere with the two former considerations. ]1.3 PART II. FORMATION AND REGENERATION OF WOODS. 115 FORMATION AND EEGENERATION OF WOODS. The formation of a wood comprises all measures having for their object the production of a new crop of trees. Such a crop can spring up from seed, sHps, layers, pieces of roots, or from stool shoots and root suckers. In some cases the forma- tion of a new crop is the result of the spontaneous action of nature, in wdiich case the forester speaks of natural formation or rcf/encration ; in others, the seed or young plants are brought on to the land by the action of man, when the process is called artificial formation. A further distinction must be made as regards the special kind of material employed in the formation of a wood. Again, two or more methods of formation may be combined. And again, a wood may be composed of a mixture of two or more species. Finally, certain preliminary works may have to be carried out before the formation of a wood can be commenced. Accordingly, this part has been divided into the following chapters : — Chapter I. Peeliminary Works. ,, II. Artificial Formation of Woods. ,, III. Natural Eegeneration of Woods. ,, IT. Formation of Mixed Woods. y. Choice of Method of Formation. - I 2 116 CHAPTER I. PRELIMINARY WORKS. Before a wood can be formed certain preliminary matters must be attended to. Tbese will be indicated in the following three sections : — Section I. — Choice of species. „ II. — Fencing. ,, III. — Eeclamation of the soil. Section I. — Choice of Species. The success of forestry depends in the first place upon a judicious selection of the species of tree which is to be grown under a given set of conditions. A full considera- tion of this matter is of great importance, because mistakes made in the selection of species cannot, as u rule, be recti- fied until after a considerable lapse of time. Most indigenous species thrive almost equally well on ordinary soils for a series of years, while those unsuited for a particular locality commence falling off only after perhaps 20, 30 or even more years. The fall success of a species depends on many things, amongst which the following deserve special attention : — (1.) Suitability for the objects of management. (2.) Adaptability to the desired sylvicultural system. (8.) Exposure to damage by external causes. (4.) Suitability of species for the localit}'. To which may be added. (").) Desirability, or otherwise, of a periodical change of siiecies. CHOICE OF SPECIES. 117 1. Siiitahiliti/ of thr Species for the Objects of Manaijemoit. The varying objects of management have been indicated on page 1. Whatever the.y may be in any special case, the species must be selected so as to do them full justice. If the object is to grow produce of a definite description, the species must be capable of yielding it ; it would be useless to grow yew for hop poles, or poplar for naval construction. Where the objects of management are governed, or influenced, by existing forest rights demanding timber or firewood of a particular species, that tree must be grown. If, on the other hand, third persons are entitled to trees of certain species, should they happen to appear on the area, the owner would not voluntarily cultivate them. Where the object is to j)roduce the greatest possible quantity of material per unit of area, that species must be selected which produces the highest average annual increment. In gauging the financial desirability of a species, the quantity and quality of the produce, as well as the expense of rearing it, must be taken into account. In some cases only certain species are saleable, while others are without value. Again, some species produce a much higher percentage of timber as compared with firewood, than others. Species with a thin crown are indifi'erently adapted for wind breaks, whereas the}' may be specially suited for nurses over a tender crop, or as standards over coppice. The above instances will suftice to show that the number of species which may be desirable in any given case is narrowed down by the objects of management. 2. Adaptability oj tlic Sjiecies to the desired Sylvicultaral System. All species of trees can be treated as high forest, but only a certain number as coppice woods. The conifers of temperate Europe either do not coppice at all, or very indifi'erently; even some of the broad leaved species do not yield satisfactory 118 I'HKIJMINAltY WORKS. resiill.s. Sliadf Itearinj^ .species are not cle.siral)le as standards in coppice with standards, A selection of species must be made accordindv. 3. K.rposiirr of ill)' Sjircirn to l)(iin(«ir h// K.ttcnial ('(Iiihch. The selection of species to be planted is further narrowed by the degree to which they are exposed to injury by external causes, as fire, frost, drought, cold winds, strong gales, insects and fungi. Conifers, for instance, are more exposed to damage by fire than broad leaved species ; larch and silver fir suffer much from canker ; spruce is liable to be thrown by wind ; beech and silver fir are frost tender, while Scotch pine and birch are frost hardy ; Scotch pine and spruce are more subject to damage by insects than any other European species, etc. All these matters influence the clioice of s^^ecies under a given set of conditions. 4. Sliildhililil of the Species Jor fJie Loeal'ttjl. From the point of view of Political Economy the improve- ment, or at any rate the maintenance, of the j-ield capacity of the land is the most important consideration. AVhether the owner of a forest be the State or a private jierson. he will find a system of management recognising that principle to l)e the most profitable in tlie long lun. Hence it must be the forester's endeavour to grow species whicli not only suit the locality, but also tend to improve it. In the first place the qualitij of the locality must be carefully ascertained, so as to avoid growing a species whicli has no chance of thriving on it. This task is by no means an easy one, because the efiects of some of the factors of the locality on tree growth are as yet imperfectly understood. The climatic factors are of special importance; hence the efiects of the geographical position, altitude, aspect, gradient, cojitour ami surroundings of the locality upon the temperature, degree CHOICE OF SPECIES. 119 of moisture and air currents must be carefully considered. The soil and, if necessary, the subsoil as well must be examined as to depth, degree of porosity and moisture, com- position and admixture of humus. The development of any trees already growing on the locality, or in its vicinity, should be carefully studied. An investigation of this kind will generally indicate what species are capable of thriving on a locality ; it should, however, not be overlooked that any species found growing naturally on the area are not always those best adapted for it, because their presence may depend on circum- stances other than a general suitability of soil and climate : for instance, a shade bearing species may have ousted a light demanding one, or a greater power of reproduction may have enabled one species to drive out another possessed of less energy in that respect. As long as the factors of the locality are fairly the same over the whole area, the latter may be treated in a uniform manner, but the occurrence of decided differences may necessitate the selection of different species for difi'erent parts. Any attempt at uniformity in spite of such differences may lead to a serious loss in returns. In order to provide for a continuous preservation of the fertility of the locality, it is necessary to select species which give sufficient shelter to the soil and a good supply of humus, or, at any rate, to mix such species in sufficient numbers with those which do not shelter the soil. This rule can only be disregarded in thoroughly favourable localities. Under these circumstances, species with dense crowns must receive special attention in making a selection for middling and inferior localities ; in addition, interference with the fertility of the soil, such as the removal of leaf mould, excessive grazing, faulty treatment, etc., must be carefully avoided. Above all, personal fancy on the part of the forester for a particular species must be set aside. Not unfrequently several species are found to be equally well adapted for a locality. In such cases other considerations izO PKEJJMINAKY WOKKS. ninst decide whicli shall be i^rown, or wlietluM- iown) 'llie natural surface line is represented by a, a, a, a, while b, 1/ are the places where the turf has been excavated, and c, c, the dyke consisting of successive layers of turf. 3. W'dodiii I'aUiKj^. There is an endless variety of wooden palings. I '^. ^:^ [^ r-a I I V V V V V V V V V I Fig. 8 shows a wooden fence, affording protection against labbits on one half of the diagram. It sufTers under tlie disadvantage thai all the upi'i.i^lit s))ars nnist be driven into FENCING. 125 the ground, which Ccauses them to rot. To reduce this danger the inserted part should be tarred or creosoted. It is far better to replace the short spars by wire netting. Frequently wood fences are made in sections, so that they can be carried from one place to another. 4. Ditches. Ditches for keeping out animals should be constructed with a perpendicular wall (a) on the inside and a gentle slope (h) out- wards (Fig. 9) ; sometimes the perpendicular side is faced by a stone wall (r) to prevent its falling in. On the whole, ditches are expensive, if constructed so as to be lasting ; hence in the majority of cases they are only used as an auxiliary to other fences, for instance a wooden paling or a wire fence (d). 0. Wire Fences. Here, again, a great many varieties have been introduced, some having iron standards and others wooden supports. In the case of permanent nurseries iron standards may be desir- able, but in fencing woods, which only require protection for a limited number of years while under regeneration, wooden supports will, in the majority of cases, be found cheaper. On 126 PRELIMINARY WORKS. the whole, for sylvicnhunil purposes, wire fences with wooden supports are probably more suitable than any other kind. Fig. 10 represents a fence consisting of wooden supports, with six wires so arranged as to keep out horned cattle, horses and sheep ; height 4 feet, a - - - a shows the surface of the soil ; h and c the two end or straining posts of a section, which O/ J d iw^ u Fig. 10. should not be further apart than ()00 feet ; d, d represent intermediate thinner posts, placed from 5 to 10 feet apart ; h and r have each six holes bored into them. At h the ends of the wires are passed through these holes, bent round the post, and fastened securely to the wires at c. At the other strain- ing post, c, the wires are strained and fastened by various contrivances, one of which is shown in tbe illustration. It consists of a screwed eye-bolt not less than 12 inches long. The end of the wire is fastened to the eye of the bolt (Fig. 11, a), and the latter passed through the hole in the straining post. On th(^ other side a nut. h, is screwed on after lirst inserting a plate or washer, r, to prevent the luit from cutting hito the wood. J3y turning the nut sufficiently the wire FENCING. 127 becomes strained. The wires are fastened to the intermediate posts by staples (Fig. 12). These are driven half-way into the posts and the wires passed through, before the straining commences. They are driven home when the straining has been completed. Fig. 13 shows a cast-iron straining bracket fastened to a wooden pillar ; this is worked with a key. It is used instead of the eye-bolt. Where rabbits or hares are to be kept out, wire netting may be added to the lower part of the fence. Fiff. 12. Fiff. U The cost of the materials in England may be estimated as follows : — Wire, imperial standard wire gauge, No. 8, about one shilling per 100 feet ; galvanised, ^ more. Straining bolts, 12 inches long, |- inch diameter, with nut and washer, tenpence each. Straining brackets (Fig. 13), tenpence each. Steel staples, per 1,000, 9s. ; galvanised, ^ more. Thus the iron materials come to about Sd. a yard, or 4d. if galvanised wire and staples are used. The cost of the posts and of labour depends on local circumstances. For nurseries iron fences may be used, to which wire netting may be added, if necessary. Fig. 14 represents such a fence. It is 4 feet high, the pillars are 2^ feet in the ground, and the fence is strong enough to keep out horned cattle, sheep, goats, hares and rabbits. The straining pillars. 128 I'RELIMINAKY WORKS. n. are so iirranged as to strain tlu' wires on liolli sides : they are usually, in this fence, placed 220 yards apart. The stan- dards, /^ are tee-irons, 1^' x li" x ^'jv", placed 12 feet apart. The top wire is fT'^lviinised barb No. 4, the three lower wires No. (> galvanised strand. The netting is li inches mesh, medium quality; it reaches 3J feet above ground, and is pegged down 0 inches along the surface outside, to prevent rabbits burrowing under it. This fence is offered in the London market for l.s-. -ild. a yard.* 6. C()iiihiiiatio)is. Frequently two kinds of fences are combined. More par- ticularly wooden palings or wire fences or even turf dykes and walls may be added to ditches, or walls and turf dykes may carry a wire fence or a wooden paling (see Fig. !)). 7. Choirr of Fence. ■ The choice of fence depends chiefly on : (1.) The time durhig which it is required. (2.) The species of animal to be kept out. If an area is to be protected permanently, or at any rate during a considerable period of time, the fence should be of a substantial nature, such as a living hedge, wire fence with * I5y tlic Iron Wire. Wire Hn|)0, and Foiieiiig t'oniiKiny. Westminster. RECLAMATION OF THE SOIL. 129 iron standards, or stone wall. For a limited number of years, wooden palings, a wire fence with rough wooden standards, or a turf dyke will be cheaper. Protection may be provided against horned cattle, horses, sheep, goats, and deer by any of the above-mentioned fences. Where hares and rabbits are to be excluded as well, wire fences, and often also hedges and wooden palings, require the addition of wire netting, or a similarly effective arrangement. In the case of rabbits and hares only, wire netting, with cheap standards, suffices ; the wire netting must go from 6 to 12 inches below the surface ; a still better arrangement is to lay it flat on the surface on the outside for 6 to 12 inches and cover it with soil or turf. Against ordinary cattle a height of 4 feet is sufficient, but against deer the fence should be 6 and even 7 feet high. Section III. — Eeclamation of the Soil. Soil may be called fertile for sylvicultural purposes, if it possess sufficient depth, a suitable degree of porosity and moisture, and a suitable chemical composition. Forest soil, if undisturbed, will in most cases maintain, or even acquire, those physical conditions which render regular arti- ficial tillage unnecessary. Immediately before and during the formation of a wood, however, certain things may have to be done to render the soil fit for the growth of trees. These measures may be divided into the following two groups : — (rt.) Eeclamation of soil unfit for the growth of trees, and (h.) Tillage of the soil concurrent with the formation of a wood. The latter will be dealt with in connection with the various methods of starting a wood. Group (a) includes the following measures : — (1.) Treatment of an impermeable substratum. (2.) Treatment of swampy ground generally. (3.) Irrigation of arid land. s. K 130 PRELIMINARY WORKS. (4.) Treatment of excessive laj-ers of vegetable matter. (5.) Fixation of shifting sand. (6.) Fixation of unstable soil on slopes. It would require a volume to itself to deal exliaustivelj- with these matters; hence, in this place, only a few short remarks can be made on the more important points. Those who require more detailed information will find it in Volume IV. of this Manual and in special works on the several subjects. 1. Treatment of an Impermeable Suhstratiim. Impermeable strata in the soil consist in some cases of an accumulation of cla}', which has bj^ degrees been washed out of the surface layers and deposited at a certain depth ; in other cases sand or gravel has been converted into a hard rock-like mass by the addition of organic matter, clay, or oxide of iron. Such a stratum is frequently called a jmn. It may be found at varying depths below the surface ; if at a depth of 4 feet or more, it does not, as a rule, interfere with the growth of forest trees, except perhaps on arid unirrigated ground, but if it occurs nearer the surface it may produce the following injurious effects : — (a.) Interference with the development of a proper root system, followed by small height growth and liability of the trees to be thrown by strong winds. {h.) Interference with the movement of water in the soil, preventing its penetration into the subsoil during wet weather, and its ascent during dry weather ; in other words, it may render the soil too wet at one time and too dry at another. The remedy is to break through the impermeable stratum, so as to connect the upper and lower permeable layers of the soil. According to the nature of the pan and its depth below the surface one of the following methods of treatment must be adopted : — (a.) Deep ploughing. RECLAMATION OF THE SOIL. 131 (/>.) Trenching. {(■.) Raising the surface level. If the lowest part of the pan is not deeper than 18 inches below the surface and not too hard, ploughing may be adopted ; the pan, being brought to the surface and exposed to the atmosphere, soon disintegrates. Pans situated at a greater depth than 18 inches must be broken through by trenching with spade, hoe, pick, or crowbar. In either case the operation is expensive, hence it is usual to treat only part of the area, in strips, patches, or holes. Strips may be 2 to 3 feet broad, separated by unbroken ground 4 to 6 feet in ])readth, so that the actual work is restricted to about one-third of the area. Patches may be of various sizes, down to holes about 12 inches square. If the pan is very thick and goes to a greater depth than 3 feet, it may be cheaper to raise a portion of the land by cutting ditches at intervals and placing the excavated earth on the intermediate strips, thus providing the latter with a depth of soil sufficient for the production of trees. The treatment of impermeable strata is always an expensive matter, so much so in many cases that the utilisation of the area becomes altogether unprofitable. In some cases the expense may be avoided by planting a shallow rooted species and being satisfied with moderate returns, 2. Treatment of Swampy Ground generally. Each species thrives best with a definite degree of moisture in the soil at all times of the year. That degree differs con- siderably in the case of the several forest trees ; while some like moist and even wet soil, others will not flourish in such localities, and none of them in stagnant water. It follows that an excess of moisture, over and above what is suitable for a given species, must be removed before a wood is started. The method of doing this depends on the cause of the excess of moisture. A locality becomes swampy if it receives more water than k2 I.'i2 PRELIMINARY WORKS. can 1)0 disposed of ]>\ evaporation, lilterinj:^ inio the snl)soil, or surface drainage. An excess of water may be due to ex- cessive rainfall, inundation, underground currents, or springs; in the first two cases the swampiness may be only temporary. The natural draining away of the excess water may be im- peded by an insufBcient local gradient, by an impermeable soil, or by both combined, the last being the usual case. ]3efore removing the surplus water from a swampy piece of ground, the expense and the effect of drainage on the sur- rounding lands should be carefully considered. The cost is, as a rule, considerable and sometimes prohibitive ; draining a swamp may, especially in a hilly country, seriously reduce the necessary degree of moisture of adjoining areas, the level of underground water, the continuous flow of water in the ordinary water channels, or even the amount of rain and dew in the neighbourhood. Existing woods, which have become accustomed to a certain degree of moisture, may thus be seriously injured.* If, after full consideration, it has been decided to remove the excess water, this can be done either by diverting the water l)efore it reaches the swampy ground, or l)y draining the latter. a. Dirrrfiion of Jurrss Wr/fcr. This is done by embankments in the case of inundation water coming from rivers in low lands, or by ditches in the case of spring water or surface drainage coming from higher ground. Inundation water moving over the surface of tlie land may be kept out of a certain locality by a surface embankment ; if the water moves underground, it can only be stopped by a substantial underground embankment, such as a stone or concrete wall. Spring water and surface drainage in hilly ground is caught * It is belic-vfd that sonic of ihv finis in tlic Lonjr AValk. Windsor Vixrk. died in cojisciiuiiici' of (ir!iinat,'t' can ird out sonic tinieajro; after tliese drains liad. ill consciincncc. bt'eu blocked again, the remaining trees recovered. RECLAMATION OF THE SOIL. 133 and diverted by runniiif:; a ditcli of suitable dimensions along the slope of the hill just above the swampy ground. The ditch intercepts the water and leads it past the swamp. In cases where the spring is situated in the swampy ground itself, only draining can meet the evil. h. Drainage. A swamp may be drained : — (1.) By increasing the gradient (or width) of existing water- courses. This is practicable when the latter pursue a winding course ; in such a case the course may be straightened, so as Fiff. 15. to increase the velocity of the current. This method is only occasionally applicable. (2.) By breaking through an impermeable stratum in the soil, so that the water can j<er into the subsoil (Fig. 15). Here a represents the water, h and d permeable strata, and c an impermeable stratum ; e the channel leading from the swamp to the lower permeable stratum. (3.) By constructing a series of ditches, or laying down a series of drainage pipes. The latter are rarely used in forestry, because they are expensive and liable to be choked by the roots of the trees. For the same reasons covered ditches are only rarely employed. The method usually followed consists in the construction of a series of open ditches, because they are comparatively cheap, whilst setting 134 PRELIMINARY WORKS. aside a portion of the area for ditclies does not reduce the returns. There may be three kinds of ditches : — (1.) The collecting ditches, or feeders ; (2.) The connecting ditches, or leaders ; (3.) The main drain. See Fig. IG. The feeders receive the water from the soil and conduct it to the leaders, whence it is taken into the main drain. In some cases the feeders fall directly into the main drain. The first step in proceeding to drain an area is to take levels, so as to ascertain accurately the fall of the locality ; if the area is of some extent, a map showing contour lines should be prepared. Unless this is done, mistakes are likely to occur in laying out the system of drains. The second step is to lay out the main drain, if possible along the natural line of drainage ; in other words, along the lowest part of the area. According to the natural fall of the land, the gradient of the main drain may have to be in- creased by cuttings, or reduced by giving it a winding course, so as to secure a suitable fall. The third step is to lay out a system of feeders, more or less parallel to each other, at a suitable angle with the general slope of the country, and to connect them at an acute angle with the main drain, either directly or through a leader, which is similarly connected with the main drain. In laying out such a system of drains, the gradient, depth, shape and distance from each other require careful consideration. The gradient, or fall, should be such that the water is carried awa}' with sufficient rapidity, without causing injury to the base and sides of the drains by the scouring action of the water. AVliere the natural gradient of the ground is in- sufficient, the base of the drain must bo sunk until the necessary fall has l)een obtained. A\ here it is too great, tlie drains must pursue a winding or zig-zag course, so as to RECLAMATION OF THE SOIL. 135 reduce the fall ; or the base and sides of the drains must be protected by a facing of stone, or fascines ; in some cases the base may be terraced. a, a. Contour lines, c, c. Wiiter parting. h. Feeders. Fig. 16. c. Leaders. d. Main drain. (The figures 170, 160, 150, and 140 give the elevation in feet above sea-level.) The maximum gradient which is admissible depends on the nature of the soil. Where the latter is of middling con- sistency an average fall of 1 per cent, would probably be 136 PRELIMINARY WORKS. indicated ; on firm soil it may be greater, on loose soil smaller. The dcptli of the feeders depends on the depth to which it is intended to drain the land ; the former must be somewhat greater than the latter. The depth to which the soil requires draining may vary from 18 inches to 3 feet, according to the species to be grown. Ash, hornbeam, and elm can do with 18 inches, while Scotch pine, beech and silver fir, prefer soil which is drained to a depth of 3 feet. u a, a. Natural level of ground. h. Feeder, four feet deep. c, c. La}-er.s of soil actually drained. Fiff. 17. (/, (/. Layers of .soil not drained. ( Id c. About three itet. Fig. IS. a. a. Natural level of ground. h, b. Leaders (five feet deep), or main drains. c, c. Feeders. Depth at upper end, 3 ft. G in., at lower end, 4 It. U in. (In these diagrams tlie height is exaggerated.) Figs. 17 and 18 illustrate the comparative depth to which a locality is drained, and that of the feeders and leaders. The sha2)e of the drains depends on the fall and on the nature of the soil ; the greater the cohesion of the latter, the steeper may be the slopes of the sides. In the case of peat, the sides may be almost perpendicular, in stift' loam they should I'urui an an<^ie oi' uljout 15 degrees, and they must become more and more slanting, as the proi)ortiun of sand in the soil increases. The base of the ditch should be at least as broad as the spade which is used in making and after- RECLAMATION OF THE SOIL. 137 wards cleaning it. For the rest, the width of the drain depends on the body of water which has to be carried away. The distance between two successive feeders depends on the permeabihty of the soil, the depth of the ditches, the depth to which the land is to be drained, and the general fall of the locality ; it will accordingly range between 30 and 100 feet. c. Raising the Level of Fart of tlie Ground. If it is undesirable or impracticable to drain a swampy area, it may, if the water is of moderate depth, nevertheless be rendered useful, by excavating part of it and using the soil so obtained to raise the level of the rest to a sufficient height so as to render the cultivation of trees practicable. a — a. Natural level of swampy groiind. h, h, h. Ridges on which the trees are to be planted. In such cases the raised parts form generally parallel ridges, as indicated in Fig. 19. Such works are expensive, and only species which stand a good deal of moisture can be grown. 3. Irrigation of Arid Land. In temperate Europe irrigation is only employed in nurseries, but in more southern, tropical and arid countries extensive areas are artificially irrigated for the growth of forest trees. The details of irrigation must be studied from a special work on the subject.* In a general way, irriga- tion may be described as the reverse of draining; thus in Fig. IG (page 135), d Avould represent the main supply * For instance. " The Roorkee Treatise on Civil Engineering in India." Vol. ii., Section x. 138 PRELIMINARY WORKS. channel, situated in the liighest part of the area, c, c, c the leaders, and h, h, h the distributing trenches. The watering of the land may be caused by overflow from the trenches, or by percolation ; in the latter case the trenches would only be just filled, and no more. "Where extensive areas are to be irrigated, the channels and trenches must be carefully laid out, with a suitable fall, so as to prevent the bursting of the channels and the silting up of the trenches. 4. Treatment of Excessive Accumulations of Vegetable Matter. Cases occur in which accumulations of vegetable matter have to be disposed of, before the formation of a wood can be taken in hand. Such accumulations may be objectionable, because they are so thick that the seedlings cannot reach the mineral soil within'a reasonable space of time, and run the risk of drying up ; or they may have become acid, or bituminous ; again, they may be accompanied by swampiness, or be liable to dry up too quickly. The following cases specially interest the forester : — a. Peal Bogs. To render a peat hog fit for the growth of timber trees, one or all of the following operations must be carried out : — (1.) Draining. (2.) Removal of at least a portion of the peat. (3.) Mixing the peat with mineral soil. The draining is done in the manner described above ; it is, however, desirable to do this gradually, so that the layers of peat may dry by degrees, to prevent the formation of ex- tensive cracks. The feeders should at first be of moderate depth, and gradually deepened, until the mineral soil is reached. AVhen the layer of peat is sliallow, it can, after draining, be mixed with the mhieral soil below it, and thus rendered EECLAMATION OF THE SOIL. 139 fit for the growth of trees ; a good plan is to grow one or two field crops on the area, before the trees are planted. If the layer of peat is deep, 3 feet and more, the upper portion must be removed, and only the remainder mixed with the mineral soil. The cut peat may be used as fuel, but if not so required, it may be cheaper to burn the upper layers in situ when sufficiently dried by the draining, the ashes being mixed with the soil. h. Accumulation of Raw Humus. This may consist of an accumulation of leaves, needles, weeds, moss and twigs, which, from want of moisture in the soil, or of heat or lime, has remained undecomposed. The case only occurs in already existing woods. To cure the evil, the wood must be thinned heavily, some time before regenera- tion is contemplated, so as to increase the admission of sunlight and air currents and accelerate thereby decomposition. If this measure proves insufficient, part of the humus must be removed, and the rest mixed with the mineral soil. c. Dry Mould and Bituminous Humus. The first is formed by the decomposition of certain lichens on over- dry soil ; the latter is the result of the decomposition of heather and various species of Vaccinium. Both are unsuited for young plants, and they should be removed. On the whole the cases mentioned under h and c occur but sparingly. 5. Fixation of Shifting Sand. Sand of a fine grain, without a sufficient quantity of binding material such as clay or humus, is liable to be blown about, and to become moving or shifting sand, which overspreads adjoining lands. If the supply is kept up, these shifting masses of sand form regular waves which proceed at a certain rate in the same direction as that of the prevailing wind. Shifting sands are most prevalent along sea shores, 140 PRELIMINARY WORKS. but occur also inluiul. In eitlier case, but especially near the sea, they are capable of forming considerable accumulations of sand, reaching a height of 200 feet and even more, which are called dunes. Before such areas can be brought under wood, it is necessary to fix them, so as to allow trees to spring up and lay hold of the soil permanently. a. Coas/ Dunes. Along the sea coast the waves constantly throw up sand, which, after drying, is carried inland by air currents, forming a series of ridges and valleys in many cases, though not necessarily, parallel to the sea shore. These sand hills move steadily forward, being replaced behind by fresh sand thrown up by the sea. The rate of progress varies considerably according to circumstances. On the west coast of France it is said to be about 14 feet a year, but as the process has gone on for a long period of time, an enormous area comprising millions of acres has become covered with sand. The further progress of the evil has been checked only in comparatively recent times by operations which it is useful to describe shortly in this place. The measures which must be taken are : — (1.) Cutting off a further supply of sand from the sea. (2.) Fixing the sand temporarily, so as to allow sowing or planting. (3.) Growing a crop of trees and bushes, which will per- manently fix the sand. (4.) Maintaining permanently a crop of trees and shrubs. The first of these four measures is based on the fact that, although air currents are capable of moving the sand along level and gently sloping ground, they cannot lift it above a certain height. Hence it is necessary, at a moderate distance (100 — 300 feet) from high water level, to form an artificial hill, which is high enough to arrest the forward movement of the sand, and this is done by the construction of an artificial dune, generally called the "littoral dune." With Ibis object KECLAMATION OF THE SOIL. 141 in view a continuous line of paling is erected, consisting of planks about 6 feet long \)y 6 inches Avide, 1 inch thick, and pointed at the lower end. The planks are inserted into the ground to about half their length, an inch apart, the direction of the line being parallel to the coast. Against this fence the sand is deposited, a certain portion being forced through the Fig. 20. a. Sea level. b. Paling iu three successive positions. c. First wattle fence, d. An additional wattle fence. e. Original surface of littoral dune. /, ff. Surface of littoral dune in two subsequent stages. (The heights are exaggerated.) interstices and coming to rest in the comparatively quiet air immediately behind the paling. As soon as the accumulation of sand approaches the upper ends of the planks they are pulled up about 3 feet by means of levers, and this process is repeated until the artificial dune has reached such a height that no sand can be carried over the top (see Fig. 20). Simultaneously with the first erection of the paling a wattle 142 rRELTMINARY WORKS. fence is placed at a convenient distance behind it, to prevent the sand which has passed through the pahng from being carried inland ; when the first wattle fence has been entirely covered, a fresh one is made to replace it. In this way the dune is forced to adopt a moderate slope on both sides, which is essential to its permanent maintenance. The latter is effected by growing on it certain plants which are capable of living under such conditions. Amongst these the marram grass, Psamma {Ammoph'da) arcnaria, takes the first place ; it has the property that, as the sand rises around it, its stalk grows higher and develops numerous adventitious roots at the joints. Other plants used for the same purpose are Eli/nnts arcnarius and Care.v arouivia. The second measure, or the temporary fixation of the area covered with sand behind the littoral dune, consists in covering the area with various materials, such as the branches of coniferous trees, heather, broom, furze, seaweed, turf, etc. ; the last, when obtainable, is best. These materials (except the turf) are kept in their place either by fastening them down with pegs, or by placing shovelfuls of sand upon them. The third measure consists in stocking the temporarily fixed area with trees, shrubs, and grasses. Of trees the Scotch pine and the cluster pine (Pin us Pinaster) are specially adapted ; seed of these may be sown or transplants put in. Of other plants Psamma arcnaria, Eh/miis arcnarius, Carcx arenaria, broom {Sarothamnus scoparius), and furze {Ule.v nana), may be mentioned. It is essential to maintain the temporary cover until it is replaced by the permanent growth. On the west coast of France the second and third measures are done simultaneously. There, a mixture consisting of 9 pounds of cluster pine seed, 8 pounds of broom, and 3^ pounds of I'samiiia arcnaria per acre are sown, and im- mediately after it the ground is covered with brushwood, which is kept in its place by occasional shovelfuls of sand. The })ineK, the broom, and the marram grass come up RECLAMATION OF THE SOIL. ]43 together, and it is said that the young pines grow all the better when surrounded by the two other species. The cost of these operations is considerable, amounting sometimes to ten pounds per acre and more ; the expenditure will not be found excessive, if it is remembered that fertile lands beyond the dunes may thus be protected against being covered by sand. I). Inland Dunei<. These are treated in a manner similar to that described in the case of coast dunes, with this exception, that the con- struction of a forward dune, corresponding to the littoral dune on a sea shore, may not be necessary. In many cases it may suffice to arrest the for- ward movement of the sand on the windward side by a wattle fence until the ground has been covered with a growth of trees, shrubs and grasses. The temporary fixation of the sand is here frequently effected by means of pieces of turf, which are laid in rows or squares, within which the sowing or planting is done (Fig. 21). In the case of both coast and inland dunes it is essential to keep all domestic animals out of the area, at any rate for a number of years after it has been fixed, as they disturb the sand. When the area has been stocked with ti-ees, clear cuttings must be strictly avoided, the wood being treated under the selection system, else the work may have to be done over again.* 6. Fixation of Unstable Soil on Slopes. Owing to the action of water, soil on sloping ground may become unstable. Water filtering downwards causes a re- duction in the cohesion of the different layers of the soil, * For further details see Volume IV. of this Manual. 144 rRELnriNARY works. followed by <];raclual deniulation, or landslips. In water channels the banks may be undermined. The result is a reduction in the productive power of the slopes, while the level ground l)elow may be covered with the del)ris brought from 'above ; at any rate the water channels in the low land silt up, and give rise to inundations. The detailed consideration of this subject belongs to Forest Protection.* It will suffice here to state that the best pre- ventive measure consists in keeping such ground permanently under forest growth, from which domestic animals sliould be excluded. If a bare area exposed to denudation is to be stocked, it may be necessary to fix the soil before sowing or planting is attempted. This is done by regulating the existing water courses, terracing them, and even erecting wooden or masonry revetments. Where necessar}-, additional water channels must be cut to lead off all surplus water into the regular channels. Cattle of all kinds must be strictly excluded. The land itself may have to be terraced, or wattle fences may be erected at suitable intervals. Only after the soil has been rendered stable can the formation of a wood be commenced. Works of the above mentioned kinds have been executed on a large scale in the French, I Swiss and Austrian Alps, as well as in the Jura. * For further details see Volume IV. of lliis Manual. t See " Traite pratique du Reboisenient et du Gazonnement des Montagnc.*," by P. Demontzey. Paris : Rothschild, 13, Hue des Saints-Peres. 145 CHAPTER II. AETIFICIAL FORMATION OF WOODS. Section I. — Direct Sowing. By " direct sowing " is understood the formation of a wood by the sowing of seed directly on the area which it is proposed to stock. This can be done in various ways. Whatever the chosen method may be, its success depends on considerations which hold good, more or less, for all ; hence, the general conditions of success must be dealt with, before a description of the different methods of sowing can be given. A. Conditions of Success. 1. Choice of Species. The considerations which guide the forester in the selection of the species to be grown have been given in chapter I. In this place attention must be drawn to the fact, that under the system of direct sowing only a moderate amount of protection can be given to the seed in the ground and to the young seed- lings which may spring up. Trees with delicate seeds and seedlings, or expensive seeds, are, therefore, less suited to this method than hardy species which thrive easily, and especially those with large seeds. 2. Qualitij of Seed. It is of paramount importance to use only good seed. The quality of the seed depends principally on its being perfectly ripe and on its weight, size, age and origin. a. Weight and Size. In the case of one and the same species large heavy seeds are better than small light ones. The former generally s. L 146 ARTIFICIAL FORMATION OF WOODS. possess a greater germinating poNver, and the resulting seed- lings show a greater power of resistance against external injurious influences, and a more vigorous development, which in many species is due to the greater quantity of reserve materials deposited in the seed. This superiority at the first start should not be under-estimated, because it is recognisable long after the seedling stage has been passed. In many cases the dominating trees grow out of the seedlings which had the best start. The actual weight of good seed varies according to locality. The following figures are given as examples ; they represent averages for clean seeds without wings calculated from the best available data : — Number of Seeds per pound. Sweet chestnut 115 Oali, pedunculate Oak, sessile 130 IGO Hazel 420 Beech 2,000 Maple (sycamore) Ash 5,000 6,500 Lime, broad-leaved 5,000 Lime, small-leaved 15,000 Hornbeam 15,000 Common elm . 00,000 Alder, common 300,000 Birch Silver fir . Austrian pine . Weymouth pine Corsican pine . . 800,000 10,000 24,000 28,000 . 32,000 Douglas fir Spruce . 40,000 . G5,000 Larch Scotch pine . 70,000 . 75,000 DIRECT SOWING. 147 b. Age. The germinating power of seed is greatest immediately after ripening ; it can be maintained for a shorter or longer period according to species and treatment. It follows that, the sooner seed is sown after ripening the better. This becomes absolutely necessary in the case of elm seed, as it only keeps for a very short time. The seeds of birch, alder, silver fir, sweet chestnut, beech and oak may be kept until the following spring, but on no account should seeds of these species be used more than six months old. In the case of lime, horn- beam, maples, ash, larch, spruce and Scotch pine seed up to two years old may be used ; if older it should be rejected. When seed is stored it must be kept free from moisture, and protected against heating by keeping it in an airy locality and turning it over from time to time. c. Source. The source whence seed has been obtained is of importance. Although trees of all ages can yield excellent seed, as a general rule it may be said that, the best seed is derived from trees which are in the prime of life, namely, healthy trees with a full crown, which have just completed their principal height growth. At the same time, soil and climate, and especially the latter, are of greater importance than the age of the trees. The question has been raised, whether it may be advan- tageous to obtain from time to time seed from another locality, as is done in agriculture. This may become desirable when the trees are affected by disease or by peculiarities which are transmitted through seed, as for instance twisted fibre ; apart from such cases, it is probably better not to change the seed. Trees live for a long space of time, and they accommodate themselves to a locality, so that home seed is likely to do best. d. Testing Seeds. The quality of seeds can be judged by their external and internal appearance. Good seeds fill up the outer coat, are l2 148 ARTIFICIAL FORMATION OF WOODS. of a good rich colour, possess a healthy smell, and look fresh in the interior when cut open. The percentage of good seed can, in the case of heavy seeds such as acorns, sweet chest- nuts and beech nuts, be judged l)y putting them into water, when those properly developed will sink, while the bad and inferior ones will rioat on the surface. When accurate information is required, regular germinat- ing tests must be applied. These consist in subjecting a certain number of seeds, usually 100, to conditions which secure quick germination, namely a steady degree of moisture, a temperature of 60 — 70 degrees Fahr., and free admission of air. Any arrangement which secures these conditions will do ; as instances the following may be mentioned : — The Pot test. — Fill a shallow, porous flower pot w^ith loose earth, place the seeds on the earth, cover them with some moss, maintain an even temperature, and water periodically, or better still, place the pot inside another containing water. The seeds should be removed as they germinate, keeping an account of them day by day. Tlw Flannel test. — Place the seeds between two pieces of flannel, or Altering paper, maintain an even temperature, and water steadily either by a spray or by connecting the flannel with a dish of water. Of late years a considerable variety of germinating dishes have been invented, but it is doubtful whether any of them surpasses the more primitive tests described above, especially the flannel and filtering paper tests. The percentage of seeds tit to germinate differs much, not only according to species, but also in diti'erent samples of seed of the same species. Seed may be considered good if a carefully conducted germinating test gives the following percentage of germinable seeds :— Spruce 75 per cent. Austrian pine . . . | Scotch pine . • • . ■ . 70 ., Corsican pine . . . ' DIRECT SOWING. Hornbeam Oak .... . 65 per cent. Ash .... ) Sweet chestnut . 60 „ „ False acacia . I Maple (sycamore and Nor way) j • 55 ., Weymouth pme i Lime .... . 50 .. ,. Beech .... ) Silver fir . . . . . 40 .. .. Larch .... • 35 ,, ,. Elm (common and mountain) [ Alder, common . 30 ,. ,. Douglas fir . ) Birch .... . 20 „ „ 149 3. Qucmtiiy of Seed. The density of a forest crop should be sufficient, on the one hand, to give a proper shelter to the soil, and, on the other, to provide for each tree that gro\Ying space which is best suited for its proper development. The first object will be obtained by thick sowing, but in that case the development of the trees would soon be interfered with ; hence a mean must 1)6 struck ; in other words, the density of the 3'oung crop should be such that a fair cover overhead will be established within 5 — 10 years after sowing. This consideration governs the quantity of seed to be sown per unit of area. The actual quantity depends on the qualit}^ of the seed, the nature of the soil, the mode of growth of the species, and the dangers to which the seed and the young seedlings are exposed. Of these the quality of the seed has already been dealt with. The Soil. — Almost any soil can nourish a full crop of seed- lings, so that the chemical composition of a soil becomes of importance only after the young crop has closed up and the struggle for existence commenced. Of far greater importance, 150 ARTIFICIAL FORMATION OF WOODS. durinp; germination and the early stage of life, are a proper degree of moisture, heat and porosit}-. A dr}-, loose, stony soil, and again a hard, cold soil, requires more seed than a fresh soil of middling porosity. The Mode of Grouth. — In the case of species which are of quick growth during youth less seed is required, than for others which grow slowly at first and do not close up for some time. External Dangers. — The seeds are liable to be eaten by animals. Amongst these birds are most injurious. To protect small seeds against birds they may be coated with red lead. Mice may be caught in traps or poisoned. The young seedlings are subject to injury by animals, fungi, the effects of climate such as frost, drought, excess of moisture, and they are liable to be choked by weeds. The quantity of seed to be sown is governed by the extent to which such injuries may be expected to take place in any given locality. Although it is, therefore, impossible to give the actual quantity of seed required in any particular case, the following figures may be taken as illustrating, under average conditions, the necessary quantities in the case of broadcast sowing, the seed being of good quality and clean : — Oak Beech Hornbeam ] Ash . j ]\raple . ^ Birch . Elm Alder . Silver fir Larch Spruce . Scotch pine Quantity of Seed in i'ouiuls |ier Acre. . 550 . 150 35 30 25 15 10 14 10 G DIRECT SOWING. 151 In the case of partial sowing the quantity of seed is proportionately smaller, thus for Sowing in strips, furrows, or trenches about 65 — 70 % of broadcast sowing. ,, ,, patches . . 50 ,, ,, ,, ,, ,, pits or holes . 25 — 35 ,, ,, ,, 4. Conditions of Germination. The process of germination is as follows : — (1.) Swelling of the seeds. (2.) Chemical change of the nourishing substances deposited in the seed. (3.) Development of the embryo. The swelling of the seed is due to the absorption of water. If then a sufficient amount of heat and oxygen are available, the reserve materials are changed into soluble substances fit for the formation of new cells ; growth then sets in, which causes an enlargement of the embryo followed by the bursting of the shell of the seed and the protrusion of the rootlet. The conditions for the successful germination of forest seeds are thus : — (1.) A constant but moderate supply of water. (2.) A temperature not lower than 45°, but better from 55—75° Fahr. (3.) Admission of air, whence the oxygen is derived. The presence or absence of light is of no importance. These conditions can easily be provided in the case of small experiments, but in operations conducted on a large scale they can only to a certain extent be secured by a suitable condition of the germinating bed, by the manner of covering the seed, and by sowing at the most suitable time of year. a. The Germinating Bed. A suitable condition of the germinating bed is of prime importance ; it is secured by working or loosening the soil, in 152 AUTIFICIAL FOltMATlUN Ol' WOODS. some instances by draininfi; or irrigating, and in exceptional cases by manuring. Loosening the soil secures the following advantages: — (1.) It enables the roots to spread more readily, and to penetrate deeper into the ground, thus rendering the young plant more independent of variations of moisture in the surface soil. (2.) It effects a mixture of the different layers of the soil, thus rendering the nourishing substances more readily available and causing greater activity in chemical changes. (3.) It freely admits air and heat. (4.) It exercises a favourable effect upon the degree of moisture in the soil. Rain water penetrates more readily and to a greater depth, while subsequently, during dry weather, it rises again by capillary attraction. On the other hand the following drawbacks must be mentioned : — (1.) On steep slopes loosening the soil may be followed by denudation, as rain water can more easily carry it away. (2.) Frost lifting may occur more frequently. (3.) It may attract injurious insects, such as the cock- chafer, the larva? of which are very destructive to the roots. The degree of loosening, and the depth to which it may reach, depend on the original condition of the soil. Hard or wet soil requires more, naturally loose soil less or no working. In some cases the actual process of loosening the soil must be preceded by the removal of an obstructive surface covering, such as woody shrubs, weeds, grass, moss, ferns, heather, raw humus, etc. ; in other cases this is not necessary. The loo.:ening itself can be done in a variety of ways ; l)y means of tools, sucli as the plough, harrow, rake, hoe, or spade; l)y DIRECT SOWING. 153 allowing it to be broken up by swine ; or by a temporary cultivation of field crops. Whether the one or other is prefer- able depends on the method of sowing and the cost of the operation. Too much moisture may prevent or retard germination, may obstruct aeration of the soil, or render it cold and cause the seed to rot. These inconveniences can be prevented either by a better distribution of the water, or by draining. The latter plan should be restricted to cases where the moisture is really excessive, and where no injurious effect upon adjoining areas is likely to be produced. In forestry it is better to drain too little than too much ; in manj^ cases the forester will do well to be satisfied with a species which will grow in moist or wet soil, rather than endanger the proper develop:- ment of valuable crops growing on adjoining lands. Irrigation may become necessary w^here the soil is ex- cessively dry. It is an expensive operation, and the necessary outlay will only be recouped in special cases. Manuring rarely occurs, except in nurseries, because it is too expensive compared with the increase in the returns which it is likely to secure. h. Time of Soicin;]. Nature sows in autumn in the case of most species growing in temperate Europe, in some cases in summer, and in others in winter or spring ; hence no absolute guide is given as to the best time for sowing. Of the naturally sown seed a large portion, while lying over winter, is eaten by animals, or perishes through adverse influences of the weather, so that only a small portion actually germinates in spring. In artificial sowing the seed must be carefulh' husbanded, hence it should be done at the most favourable season for germi- nation, namely, wdien the soil is sufficiently moist and wheu sufficient heat is available. The best time for sowing in temperate Europe is during April and May, according to the local climate. 154 ARTIFICIAL FORMATION OF WOODS. The above rule is subject to exceptions, because some seeds will keep in good condition only for a very short period, or their preservation involves much trouble and expense. The seed of the elm ripens, on an average, at the end of May or in the early part of June, and loses its germinating power very rapidly ; hence it should be sown at once. Birch seed also should be sown as soon as it ripens, about the beginning of August. The seed of silver fir ripens in autumn, and, as it does not keep well, it should be sown at once, and not kept till spring. Many foresters prefer sowing heavy seeds, like those of oak, beech and sweet chestnut, in autumn, because they are bulky and it is expensive to keep them in good condition over winter. At the same time these heavy seeds are much exposed to attacks by animals during winter, and as autumnal sowings germinate early in spring the seedlings are exposed to late frosts ; hence, sowing them in autumn may be of doubtful expediency. In some cases autumn sowings are indicated in localities which are not accessible until late in spring, such as high altitudes where snow does not disappear before June. Again, alder seed is frequently sown in winter, immediately after harvesting, as it is difficult to keep until spring. To sum up, it maybe said that in' temperate Europe spring sowing should be the rule, but that certain species and certain local conditions demand exceptional treatment. In other parts of the world, under different climatic con- ditions, the best time for sowing also varies according to circumstances. In the Indian plains and low hills the general rule is to sow at the commencement of the summer rains, because the seeds will then be assured of a sufticient supply of moisture, and the seedlings will have time to establish themselves thoroughly in the ground, before the next dry season comes round. Sowings on irrigated lands can be made at other seasons. The seed of some Indian species does not keep, and indeed the seed of Sal {Sliorm robusta) often germinates before it falls, and must therefore DIRECT SOWING. 155 be sown as soon as it ripens. In those regions of the Himalayas, where snow may lie until late in the spring, both autumn and sj)ring sowings are made, there being perhaps no decided balance in favour of the one or the other season. r. Coverinfi Vie Seed. The objects of covering the seed are chiefly the following : — (1.) To protect it against sudden changes of moisture and temperature. (2.) To protect it against being eaten by animals, especially birds, or being carried away by wind or water. In natural woods large quantities of seed fall to the ground ; some of it is carried by rain water through the vegetable covering down to the mineral soil, thus finding conditions favourable for germination. In artificial sowings the necessary protection is afforded by covering it with earth to a certain depth. The thickness of the covering is of considerable import- ance ; if too thin, the seed is exposed to attacks by animals, is liable to dry up or to be injured by frost ; if too thick, germination is retarded, the seedlings have great difficulty in pushing through the covering, and germination may altogether fail for want of sufficient air. The actual thick- ness depends on the general condition of the seed bed and the species. It must be thicker in the case of loose or dry soil, and thinner in firm or wet soil. The seed of different species requires a different covering. On the whole, large seeds, such as acorns and chestnuts, require the thickest covering ; considerably less, the seeds of beech, maple, hornbeam, silver fir ; less again, those of alder, ash, Scotch pine, spruce, and larch ; least, those of elm and birch. According to experiments made by Baur* on loamy sand * Late Professor of Forestry at the University of Munich. 156 ARTIFICIAL FORMATION OF WOODS. the best results were obtained with coverings of llie following tliickiiess : — redunciUate oak .... 1-50 inclies. Beech -75 ., Sycamore and silver fir . . . 'GO „ Scotch pine and spruce . . . ';jO ,, Common alder . . . . "40 „ Larch . . . . . '35 ,, Ehu -12 „ The seed can be covered in various ways, by ploughing (in the case of acorns), harrowing, raking, light hoeing, or by scattering fine earth over it. Some small seeds, such as that of Ficus elastica, need not be covered at all. <1. Sproutinfi nf the. Seal. During germination the rootlet is first developed, and then the stem ; as soon as the latter breaks through the surface of the soil, the seed is said to sprout. A few European species, such as oak, sweet chestnut and hazel, leave their cotyledons below the surface, but the majorit}' bring them above ground. The interval of time between the sowing and sprouting depends on the species, the age of the seed, and the conditions of germination. S})ccic>i. — Good seed sown in spring, under average con- ditions, may be expected to sprout after a lapse of time ranging from a week up to two and even three years. The following data may be taken as illustrations : — Poplars and willows . . after about 1 — '2 weeks. Elm and birch 2 — 3 Scotch pine, black pine, Weymouth pine, and larch ,. ,, 3 — 4 Spruce, silver fir ,, 3 — 5 Oak, beech, maple, and alder . .. ,. 4 — (> Ash, lime, hornbeam, and Cembran pine generally after one year, yew after one and often two and even three years. DIRECT SOWING : BROADCAST. 157 Age of Seed. — Fresh seed germinates always quicker than old, the latter sometimes not mitil the second year. The time of sprouting dej^ends much on the conditions to which the seed is subject ; a heavy covering retards germina- tion ; warm soil and sufficient moisture produce quicker sprouting than cold soil or drought. Seeds are sometimes specially treated with the object of ac- celerating the sprouting. Amongst the various methods which have been recommended the following may be mentioned : soaking in water, ranging from an hour to a week ; treatment with lime water or highly diluted hydrochloric acid ; steaming ; soaking in liquid manure. Apart from the first mentioned, great care is required in applying the various treatments, else the seeds may be injured. In the case of large seeds, like those of teak, collecting them in a heap and keeping them continuously moist may considerably accelerate germination. Seeds which germinate only in the second year may be bedded in sand in a ditch or pit, and sown in the second spring. B. Methods of Sowing. In the course of time a great variety of methods of sowing have been elaborated. It would be beyond the scope of this book to describe them all in detail ; moreover they can only be fully understood by studying them in the field. Hence, only the more important methods will here be mentioned. Sowings may be divided into : — (1.) Broadcast sowing. (2.) Partial sowing. 1. Broadcast Soicin>oiciii(i iu fiirroics ; it is specially employed in the case of heavy seeds, which are sown in the furrow and covered, either by drawing a second furrow or with the rake or hoe. It admits of a further reduction of expenditure as compared with regular strips. //. Soiriny in Patrlu'><. The seed beds consist of round, oblong, square or rectan- gular patches of limited extent, scattered as evenly as prac- ticable over the area. The extent of the patches varies according to circumstances ; they may l)e of any size, but are mostly from 1 to 3 feet square, or they assume the shape of DIRECT SOWING : IN PATCHES. 165 inteiTupted strips, which are from 1 to 2 feet hroacl and perhaps from 3 to 10 feet long. The distance hetween the patches depends on the same considerations as in the case of strip sowing. The method is cheaper than the regular strip sowing ; it enables the forester, on uneven or rock}' soil, to select the most suitable spots for the seed beds, a matter of greater moment than a mathematically even distribution of the patches. The working of the soil is l)est done with the hoe ; on stony soil hoes with narrow and very strong blades are used, or even the pick ma}' be required. The seed is covered with the rake or by hand, or by scattering earth over it. The method is well adapted for rocky soils, and localities which still contain the stumps and roots of a former crop of trees. It is less to be recommended for wet soil, as the water is likely to collect on the seedbeds ; this would, on the other hand, be an advantage in localities with a scanty rainfall. Where a strong growth of tall weeds is apprehended, the patches must be of sufficient size to prevent the plants from being overgrown. Fig. 37. a, a. Sown patches. Ififi AKTIFiriAL FORMATION OF WOODS. '■. Sorri/ii/ ill Holes, or liibhlimj. Sowing ill holes means sowing in patches of such Hniited extent that only a few seeds are sown in each. The soil may he worked with an ordinary hoe of small size, with a spade or with specially constructed modifications of tlie latter, such as the siim-cd spath- (Fig. 38). On stony soil the pick may he used. The spiral spade is forced into the ground and then turned round, so that a seed hole filled with loose soil is produced. The seed is either pressed into the soil to the required depth, or placed on the surface and covered hy hand with a sufficient quantity of fine earth, which is gently pressed down. If the seed hed is still smaller and consists simply of a narrow hole sufficient to take one or two seeds, which are sown without any preparation of the fsoil, the method is called " ilih]>}iit;i." The minute holes are made with a peg, dihbling mallet, dibbling spade, or any other suitable tool. The instrument is inserted into the ground to the required depth, withdrawn, the seed placed in the opening thus produced, and the latter closed again either by one or more blows with the instrument, or by pressure with the foot. In some cases the operation may l)e done without any instrument at all, by removing a small (luantity of the surface soil with the foot, inserting the seed, replacing the previously removed eaith. and pressing it down. The luelhod is only admissible on soils wliicli are not subject to a heavy growth of weeds, which would probably smother the young seedlings ; moderately sized stones or gravel do not interfere with the adoption of the method. Fijr. 3S. DIRECT SOWING I IN TRENCHES. 167 (L So/ring in 7Vmrhes, or Pits. In the methods so far described the seed bed is situated on the same level as the surrounding ground. In the case of trench and pit sowing it is placed below the ordinary surface of the ground, at the bottom of a trench or pit, in which water may collect. The general arrangement of the trenches or pits is the same as in the case of strips or patches respectively. Trenches must be level, to prevent their be- coming water channels. For the same reason they should be interrupted here and there. The width of the trenches will, as a rule, not exceed two feet at the bottom; the depth depends on the requisite Fi-. 3y. a. Soil taken out of the trench. b. Trench filled with water. c. Seed-bed. amount of water. The distance between the ditches or pits depends on the same considerations as in strip and patch sowings. The trenches may be made with the spade, hoe or pick, or partly with the plough and the rest with those tools. The surface soil is kept apart and placed at the bottom of the trench to serve as a seed bed, or better still, it is at once placed into the previously made trench. The seed is sown by hand and covered either by hand or with a rake. Where the trenches can be filled artificially with water, or irrigated, the seed is frequently sown on the upper edge of the ditch (Fig. 39), so that it receives sufficient moisture by percolation, without being destroyed by an excess of water. Where irrigation water is not available, and the 168 ARTIFICIAL FORMATION OF WOODS. rainfcill varial)le, seed may be sown both at tlie bottom of the ditch and along one of the upper edges. In the case of a scant}- rainfall the former will succeed, and in case of a wet 3'ear, the latter. The method is indicated in dvy hot localities, and where irrigation is practicable. As it is expensive, it should be adopted only in cases where a cheaper method is not likely to yield satisfactory results. The pit method is cheaper than trench sowing, but it frequently yields less favourable results, and is not applicable where irrigation is contemplated. e. Sotriiifi on Kiihjes and MouikIs. This method is the reverse of the one described under d. It is advisable in the case of wet or heavy soil, the object being to raise the seed bed above the water level, and to expose the soil to a more complete action of the air. Mounds are interrupted ridges, just as patches are interrupted strips. The ridges or mounds are formed, either by drawing together the surface soil, or better by excavations. In the case of ridges the ditches run along either one or both sides ; in the case of mounds the earth may be taken from an excavation on one side, or from a trench surrounding the mound. Where a moderate elevation suffices, parallel ditches may be dug, and the excavated earth spread evenly over the inter- mediate spaces, thus forming elevated platforms on wliicli the seed is sown. See Fig. 19 on page 187. The seed should be sown densely and not too early in spring, so as to allow a portion of the moisture to evaporate before sowing. The tools used are the same as for trench or pit sowings. The method is expensive and only indicated in exceplioiuilly unfavourable localities. /. ('onthindHdiif'. It happens not unfre(|U('ntly. that two or more of the different methods ar(; combined in tlio same locality. Such fonibiiiations are indicated when the character of the locality PLANTING 169 changes from place to place ; if, for instance, dry spots alter- nate with swampy ground, the former may be sown on the natural level or in ditches, while the latter necessitates sowing on ridges. Where free soil alternates with stony or rocky parts, the former may be sown in strips, and the latter in patches or holes, etc. Section II. — Planting. By the term planting is understood in sylviculture the method of forming a wood by means of plants which have been raised elsewhere. The success of the operation depends, as in direct sowing, on many matters, which hold good, more or less, for the different ways in which the actual planting is carried out. The business of raising the plants is in itself one of great importance. Planting with slips, layers, etc., again, is so different in many ways from the planting of seedlings, that it will be considered separately. Hence, the subject now under consideration may be divided into the following four sub-sections : — A. Conditions of success. B. Piaising plants. C. Methods of planting. D. Planting of slips, layers, and suckers. A. Conditions of Success. This subject may be dealt with under the following headings : — 1. Choice of species. 2. Different kinds of plants. 3. Quality of plants. 4. Age and size of plants. 5. Season for planting. 6. Density of planting. 7. Distribution of plants over the area. 8. Number of plants per unit of area. 170 AHTIFICIAL FOKMATION oF WOODS. !). Liftiiif]; plants. 10. I'liining. 11. Protection in transit. 1-J. Preparation of the soil. 1. Clinicc of Sjx'iies. Reference is invited to what has been said in chapter I., section I. of Part II. In addition it remains to be men- tioned, that planting is admissible in the case of all species, and that it is specially adapted for those which are tender during earl}- youth, and which cannot receive sufficient atten- tion and protection in direct sowings on a large scale ; also to species the seed of which is expensive, or exposed to dangers from animals, 2. Dift'i'i-rnt Kinds of Planta. The plants used in sylviculture are of many kinds, according to external form, origin, age, etc. No general classification is possible, since the various groups overlap each other. For practical purposes the following divisions will prove useful : — A distinction must, in the tirst place, be made between plants which have sprung directly from seed, and those which formed part of an already existing individual ; hence the division into : — (1.) Seedling plants. (2.) Suckers, layers, or cuttings. All woody plants can be successfully raised from seed, but only certain species from suckers, layers, or cuttings. Hooted plmits are distinguished from plants irithoitt mots. Seedlings, suckers, root cuttings, and layers when they have become independent individuals, are rooted ; cuttings taken from the stem or branches are without roots at starting, but they may i)econie rooted by placing them in a nursery before putting them out into the forest. Coniph'tc or htfoiiiplvtc jilanis ; tiie lormer have their roots, PLAXTIXn: QUALITY OF PLANTS. 171 stem and branches entire, while in the case of the latter parts of the plants may have been pruned away. S('cdUu[is or transplants. — The former are plants which are transferred direct from the seed bed to the forest ; the latter those which were previously pricked out, once or several times, in the nursery. Plants n-ith balls, or lumps of earth in which the roots are embedded, or plants a-'ithout balls. Plants may be classified, according to size, as small, middle sized, and large plants, but the limits of each class differ according to the kind of plant, as well as to locality an 1 custom. 8. Qnalitu of Plants. The success of planting operations is governed by the quality of the plants which are used, just as the success of direct sowings depends on the quality of the seed. Hence, only healthy, vigorous plants should be used, which are likely to bear well the interruption of growth involved in the transfer from one locality to another, under circumstances admitting only of a limited amount of attention being paid to each plant. The vigour, or growing power, of a plant is indicated by a normal shape and a healthy appearance. The development of each part must be in due* proportion to the rest ; the plant should be neither tall nor thin, nor too short and stout; nor should the stem be crooked, especially in the case of coni- ferous plants ; the root system should be ample, with a fully developed system of rootlets ; the crown should have a healthy green appearance, and possess numerous well developed buds. These are the general characteristics of good healthy plants. At the same time they are subject to some modifications as regards species, age, and the locality which it is proposed to plant up. More especially some caution is necessary in trans- ferring plants from a rich to a poor soil ; from a cool northern aspect to a hot southern one ; from a low to a high situation ; from a sheltered to an open spot, etc. ; in other words, what 172 A1{TIF1('IAL FOinrAIIoN OF \V(>(>I»S. is a good pliiiit for one locality, may l)e only an inditVcifnt ono for a locality of a different character. A further niodilication may be introduced o\vin,\' to the cost of raising the plants and of planting them out. Plants with naturally extensive root systems either cost much to plant out, or the roots must be crowded together in an un- natural position ; from this point of view a compact root system may be considered as an essential point in a good plant, though it may not be altogether in proportion to the stem and crown. 4. A/ Plants. Plants aged from a few weeks up to ton and more years may be planted out ; in fact the age is only limited by the size and weight of the trees, and the mechanical appliances available for the transfer. In sylviculture only young plants under ten years of age need be considered. It may be said, as a general rule, that young plants are best, because the operation of planting is cheaper, the plants survive more easily the interruption of growth involved in the change, and they adapt themselves more readily to new conditions. The best age for planting out depends on the species and locality. Quick growing species can be planted out earlier than slow growing ones. Some tropical species grow so quickly that the most suitable age for transplanting may be only a few weeks. In the temperate climate of Europe yearlings, with the exception of Scotch pine and oak. are only exceptionally planted out, as they are still too soft and have incomplete root systems. In the great majority of cases plants from two to four years old are used, while older plants are indicated only in the case of a few species, or where trees of some height are rcMjuired, as in pastures, in frost localities, for lilling up blanks in already fornied plan- tations, to become the overwood in coppice with standards, to enable one species to hold its own against another of quicker growth, for avenues, etc. SEASON FOR PLANTING. 173 5. S<'aso)i for Plantinq. The planting out is, after all, a violent operation, and is generally accompanied by more or less injury to the root system, with a temporary interruption of the growth. These disadvantages can, by special care, be reduced to a minimum, so that they affect the further development of the plant only to a limited extent. As long as the root system is completely embedded in a ball of earth, transplanting can be done at any time of the year, provided the soil is in a fit condition (neither frozen, nor too wet or dry). Again, plants, the roots of which are not embedded in a ball of earth, can similarly be trans- planted with success, provided the operation is performed with care ; but as this involves extra expense, it is difficult to ensure success in the case of large operations ; hence, for sylvicultural planting, the most favourable season should always be chosen. The most favourable season diiiers according to the character of the locality. In temperate Europe summer should be avoided, because at that time the plant is in full assimilating activity and most sensitive to a change of conditions, espcially to drought. There remains then the period from autumn to spring. Planting may be done at any time throughout that period, provided the weather be sufficiently favourable; at the same time mid-winter is generally the least favourable part of this period, as frost may be expected, so that practically the choice lies between autumn and spring. Each of these two seasons has its advantages and drawbacks, and the question, whether the one or other is more favourable, has been much debated. In the case of autumn planting any rootlets, which have been injured during the operation, may have been replaced by the ensuing spring, and the loosened earth settles down again during winter. On the other hand, the plants are likely to suffer from severe frost in their new home, or they may be lifted by alternate frost and thaw, or loosened by the action of 174 ARTIFICIAL FORMATION OF WOODS. wind. Autiiinn plantin}:; is preferiiMe in the case of localities which are not accessible until late in spring, or of sj^ecies which start early in spring. Spring planting has the advantages that the period of severe frost is past, and that vegetation begins shortly after planting. On the whole it is preferable to autumn planting in the case of most conifers, provided the work can be com[)leted before vegetation begins. In many cases, especially when the operations are conducted on a large scale, l)oth spring and autumn planting have to be done. Over the greater part of India the most favourable season of the year is the commencement of the summer rains ; the plants receive sufficient moisture, and they have the whole growing season before them to settle down in their new home and to get strong before the next dry season comes round. Land which can be irrigated may be planted at any season, provided the soil is not frozen. Ij. l)eiisiti/ of Plantiiui. The general principles which govern the density of direct sowing apply also here ; that is to say, the cover overhead Klif)uld ])e estal)lished within a period of from 5 to 10 years. As plants come on more regularly than seedlings grown on the spot, a smaller number per acre suffices, than that required in the case of sowing. For the rest the planting distance depends on :^- (a.) The locality, in so far as it iniiuences the percentage of failures and the vigour of the plants, (b.) The species, especially its degree of hardiness and rate of height growth in early youth. Quick growing species can be planted farther apart than slow growing species. Oak aiid Scotch pine must be planted dense, on account of their tendency to branch. (c.) The age and size of the plants; young and small plants must be planted closer than old and large ones. DISTRIBUTION OF PLANTS. 175 (d.) The objects of the plantmg, whether timber or fire- wood is to be produced ; whether pieces of large diameter or long boles are the objects of manage- ment ; whether the wood is to serve as a protection against landslips, erosion, avalanches, hot or cold winds, etc. (e.) The state of the market ; where small produce is saleable at remunerative rates, dense planting is indicated ; under the opposite conditions wider planting is more profitable. 7. Distrihiitinu of Plants over the Area. The distribution of the plants over the area to be stocked can be either irregular or regular. The former is done by eye measure, that is to say, after the average distance between the plants has been fixed, the planting spots are selected by eye. This system requires practice. Kegular distribution is done according to geometrical figures, the more usual of which are the following : — (1.) The equilateral triangle, where the planting spots are at the three coiners of the trinagle (Fig. 40). (2.) The square, four plants being placed at the four corners of the square (Fig. 41), (3.) Equidistant lines or rows, in which case the plants stand at shorter intervals in the lines than the distance between the lines ; the plants may be said to occupy the corners of rectangles (Fig. 42). (4.) The quincunx form, a modification of the square form, as will be seen on reference to Fig. 43. A regular distribution of the plants has the following advantages over an irregular one : — (i.) An equal growing space is allotted to each plant, (ii.) The plants are subsequently easier to find and protected against being overgrown ; failures are easier ascertained. 176 AHTIFKIAI, FOiaiATIoN OT WOODS. (► { T 1 t 1 • II » 1 i 1 Fi-. 40. Fijr. 41. • * < ' ♦ • • • < ► ( > ( ► ( t • > « . < ► ( ► < ► ( » ( > , . > i i i i 4 1 ( I 1 ► • • < I o o o o i t — I — • — ; — i * — I — < ► — I — ( > o o O o < t — ; — • — ; — < > — I — i > — \ — < I <► 1 ( H \ i i \ < ► \ ( i I I I I Q O O Q <» • it • # Fiff. 42. Fi-. 43. (iii.) Tlie area l)et^Yeell the iilaiils can he more iullv utihtsed ; grass cutting can be allowed at an earlier stage : field crops uia\- be grown between the lines ; cattle grazing, where unavoidable, causes less damage, esiiecially if the plaiits are arranged in lines. (iv.) In mixed woods the several species can he more evenly mixed. DISTRIBUTION OF PLANTS. 177 (v.) Early thinnings are considerably facilitated. (vi.) The woods can be more easily protected against damage, especially by injm-ioiis insects, or fire. (vii.) It is claimed that regular plantings are cheaper to execute, because the work of distributing and putting in the plants proceeds in a more systematic manner. Whether this advantage is realised or not, depends on the skill of the labourers and the supervision exercised over the operations. Against these advantages it must be mentioned that air currents have more easy access to regular plantations, may sweep away the fallen leaves or heap them together, and dry up the soil more rapidly. This disadvantage can be met by planting shelter belts of trees with branches down to the ground against the prevailing wind, or, to some extent, by arranging the planting lines at right angles to the wind direction. It is also claimed, that irregular planting is preferable from an aesthetic point of view. A completely regular distribution is not practicable where the nature of the soil changes rapidly ; for instance, where wet swampy spots alternate with dry parts, or where rocks are scattered over the area ; nor is it necessary on small blanks scattered over already existing woods. The comparative merits of the three principal forms of regular distribution have been much discussed. The triangular form allots to each plant the most regular growing space, since every plant is equi-distant from its neighbours ; this favours an even development of the trees. It admits of a greater number of plants per acre, and produces the greatest quantity of material ; the saplings also clear themselves more readily of their lower branches. On the other hand, it is more troublesome to lay out and more expensive than the two other forms. Line planting has the disadvantage that the cover overhead is somewhat later established, that the saplings develop stronger branches on two sides than in the direction of the S. N 178 ARTIFICIAL FORMATION OF WOODS. lines, which may be accompanied In- an eccentric shape of the stem. On the other hand, it admits of the most complete utiHsation of the Ki"ound between the lines, and facilitates thinnings and the removal of the material ;• the i)lants are also easier to find. On the whole, these advantages and disadvantages are not of much importance, because after the early thinnings the three forms stand practically on the same footing. Many foresters prefer line planting to the two other forms, because it is easiest to carry out, and perhaps the cheapest. Others Fig. 44. prefer the square form, while the triangular form is perhaps less frequently chosen. The marking of the planting spots is done with two lines (or chains), the so-called directhuj liitr and the planthifi line. The latter is divided according to the planting distance, each division point being marked in a suitable way, either by a knot, or by drawing a coloured tape through it. On the directing line the distance between successive rows is marked in a similar manner. In the case of square planting the marking is the same on both lines, but different in triangle and line planting. In the latter each division of the directing line is DISTRIBUTION OF PLANTS. 179 equal to the distance between the rows : in triangle planting equal to the planting distance multiplied by •866. The lines are of a suitable length, with a pin (or peg) at each end ; they should be made of hemp and well tarred, to protect them against moisture. On wet soil a thin chain is preferable to a line, as the latter is liable to alter its length. When a large area is to be planted, it is desii-able to sub- divide it, in the first place, into squares or rectangles, the sides of which correspond with the lengths of the planting and directing lines (Fig. 44). After the corners of the squares or rectangles have been fixed, each plot is treated separately ; the directing line is stretched along two opposite sides of it (say a d and h c), and the directing spots marked either by the insertion of small pegs or by small holes, or two directing lines may be used and left on opposite sides, until the square, or rectangle, has been planted; then the planting line is first stretched along a b, and successively parallel to it until d c is reached, planting being done as indicated by the marks on the planting line. It remains to note that in the case of triangle planting the planting line must be doubly divided, as the plants in every two adjoining rows are shifted by half the planting distance ; or the planting line must be drawn back by half the planting distance in every alternate row. The following semi-regular system of planting is much followed in Great Britain : — The planters are arranged in line at stated intervals along one edge of the area (Fig. 45, a h). Each puts in a plant where he stands. The most reliable planter is placed on one flank at a, and he now advances a space equal to the fixed planting distance in the direction of a previously erected mark (flag), puts in a second plant, advances again the planting distance, puts in a third plant, and so on, until he reaches the opposite edge of the area. As soon as the flanking man has advanced twice the planting distance, the next planter advances one planting distance, keeping at the original distance from the N 2 isn AKTIFiriAT- FORM.\TI().\- OF WOODS. first mail's line, and puts in a plant. "When the flankinfjj man proceeds to his fourth planting spot, his neif^dibour proceeds to his tliird, while the third man advances: and so on. until ^ ® ® A ® • • //. Orijjiiiiil po.-itidu of plunieis. v, d. I'osition when the whole oohiiiiii is ii on. O Fhiukinj;: man, who gives the direction. the whole column is in motion, forming' a slaiitin.i;- line (r d), each man taking his direction from his neighbour, who is always one planting distance ahead of him. "When the last niiui has reached the oi)posite end of the area, the whole NUMBER OF PLANTS. 181 column wheels round and works back again, the flanking man taking his direction from the last row of plants. The method is exceedingly simple, and yields a degree of regularity sufficient for most purposes, provided the men are well trained for the work. 8. Xtuiiher of Plants. In the case of irregular planting the number of plants required per acre can be roughly ascertained by dividing with the square of the average planting distance, given in feet, into 43560 the number of square feet in an acre. For regular plantations the following calculations apply : — Line planting : — Length of area ^ L Breadth ,, = B Distance between the rows . . . = d ,, ,, plants in the rows . = d' ; then the number of rows = , + 1, and the number of plants in each row = — + 1, d hence the total number of plants: — N = (I; + l)x(B+l) = Ii4B + L+B . V d / \d' J d X d d d' Square plantin feet X r, feet = 1,223 1.210 LIFTING PLANTS. 183 9. Lifting Plants. Plants must be lifted in the nursery with the least possible damage, especially to the root system, and least of all to the fine rootlets through which the nourishing sub- stances are assimilated. These fine rootlets are generally imbedded in small lumps of earth, which should not be shaken off. In the case of yearlings the rootlets are found on the taproot or its branches ; on older plants they are princi- pally found on the side roots. The least interference with the roots occurs, if the plants are lifted with a ball of earth, in which the root system is imbedded ; this method is spe- cially recommended for very young or tender plants. In the case of older plants lifting with balls and transport become very expensive, so that, whenever admissible, they are lifted with- out balls of earth. CL Lifting Plant with Balls of Earth. Fig. 45. The operation is performed with a variety of instruments, such as the circular spade, the hoe, the conic spade and the ordinary spade, according to the size of the desired ball. Young plants, up to a foot in height, may be lifted with the circular spade (Fig. 46), provided the species does not develop a long taproot at an early age. This instrument, which was invented by Carl Heyer about 70 years ago, consists of an iron l,bl. AiniFlCIAL KOKMATIO.N <>r WOODS. inverted truncated cone, wliicli has in frniit an openin*; sufficient to admit two fingers, and l)eliind, just above its upper edge, a small horizontal plate up to which the spade should be inserted. One of the edges of the front opening is sharp, the other blunt. The diameter at the lower end ranges from 2 to 5 inches, according to the desii-ed size of the ball ; the diameter at the upper end is from i to I larger, thus producing the shape of an inverted truncated cone with a circular cross section. The handle and the cross bar or crutch at the top are best made of wood and not of iron, because the tool is lighter and the crutch not so cold. The crutch is firmly attached to the handle by means of three iron bands, as seen in the illustration ; these are firmly fastened to the spade. The best length of the crutch is about 20 inches, and its thickness such as just to fill the hand of the labourer. The length of the handle depends on the height of the labourer, but it should not l>e so long as to prevent the man from using the weight of his body in driving the spade into the ground. In using the spade the stem of the plant which is to be lifted is passed through the front opening until it occupies the centie of the spade ; then the latter is pressed down vertically until the plate at th(i l)ack touches the surface of the soil; it is then turned round by means of the crutch from 180 to 8G0 degrees, and lifted with ball and plant out of the ground ; holding it then with the left hand, the ball and plant are pushed out towards the handle with the middle finger of the right hand, which glides along the ])lunt edge; of the front opening; if necessary, especially wluni using a larger sized spade, two fingers are used. The circular spade is used of various dimensions, with a minimum diameter of 2 inches at the small end. Spades of more than 5 inches diameter cannot be recommended, as the balls are either not severed at the bottom or. even if severed, do not come out with the spade, but remain /// sifn. l^ven small spades demand a fairly binding soil, or (dse they will LIFTIiNG PLANTS. 185 not work satisfactorily. The height of the spade is al)out equal to the diameter. The ball is cylindrical, the object of the conical shape of the spade being to facilitate its removal. The instrument works expeditiously and cheaply ; extensive areas have been planted with it. The seedlings are obtained by broad-cast sowing. The instrument is also very useful in lifting plants and planting them into blanks on areas which ^^ Ficr. 47. Fisr. 49. had been previously sown, and where the plants have come up irregularly. The hoe is also used for lifting young plants with balls ; it is inserted from one side so as to get underneath the plant, which is then lifted up. The operation requires skill, and even then the method is of doubtful utility, as the balls are likely to fall to pieces. The ordinary plantinri spade (Fig. 38, p. KU) and the Trhlt spade (Fig. 32, p. 161) are used for the I8t; ARTIFICIAL FORMATION OF \VOOl)S. lifting of larger plants. The operation necessitates four insertions, and it produces an inverted pyramidal ball. The scmi-ciiri(l(ir spade (Fig. 47) is also used for lifting larger plants; it necessitates onlj^ two or three insertions. The semi-conH-al spade (Fig. 48), invented by Edward Ileyer, is so constructed that it requires only one insertion, after which it is turned round its axis, thus separating a ball of earth of an inverted conical shape. The instrument can be recommended. On stony soil a heavy, specially strong spade (Fig. 49) is sometimes used. h. LifHiifj Plaals without Balls of Kurlh. This is best done with the two, three or four-pronged fork (Fig. 35, p. 161), which is inserted from one side and bent down backward, so that the plant is gently lifted up and gradually separated from the soil. Another method is to insert two spades or forks from opposite sides, in a slanting direction, so that they meet, or nearly so, underneath the plant ; both spades are then bent back and the plant lifted. Sometimes hoes, ordinary oi' pronged, are used, but they are inferior to spades or forks for lifting plants. PuUing up plants injures the roots and should be avoided. 10. I'nininii Plants. As a general rule plants should not be pruned unless it is absolutely necessary. Every cut produces a wound, exposing the plant to disease, which may ultimately render it uniit for the purpose for which it has been grown. Research has shown that the unhealtiiy condition of timber trees may be due to spores of fungi entering their tissue through wounds received at a very early age. Where woods are grown for fuel, or treated under a short rotation, tlie above consideration is of comparatively small importance ; in the case of timber jjlantations, however, PRUNING PLANTS. 187 which require long periods of time to mature, the forester will do well to pause before he proceeds to prune his plants. Healthy plants of moderate size can be produced at such a low cost, that it is far preferable to throw away badly-shaped plants than to prune them and risk the introduction of disease. In the case, therefore, of small and moderate-sized plants pruning should be avoided. Such plants should be so grown that a compact root system may be produced which does not require pruning. Where large plants are used, pruning may be necessary ; its execution depends on a variety of circumstances, of which the following may be mentioned : — a. Shape and Condition of Plants. In the ease of plants of a normal shape, especially if the root system and crown are in proper proportion, pruning is not necessary. In the reverse case, either the root system or the crown and even the stem may be reduced in extent ; of two leaders one may be removed, abnormally strong side branches shortened, inconveniently long tap or side roots reduced. The pruning of one part may necessitate the pruning of the other, so as to establish a due proportion between them ; if, for instance, the root system has been pruned but not the crown, portions of the latter may not receive sufficient nourishment and dry up. Originally normal plants frequently require pruning, because the root system has been injured in lifting them. t). Species. There is a great difference in the treatment of plants of different species ; some stand pruning better than others, both as regards the replacement of the pruned parts and the extent to which they are exposed to disease. On the whole, conifers stand pruning badly. Larch is perhaps an exception, also deodar and Pinus longifoUa, though they cannot be pruned to the same extent as broad-leaved 188 AHTIFlflAL FORMATION OF WOODS. species. Tlie latter recover luucli (juicker, especially species with a strong reproductive power after injury, such as willow, poplar, oak, hornbeam, elm, alder. Beech and birch, on the other hand, are less vigorous in this respect. Teak stands much pruning of the crown, but less of the root system. c. Lonilili/. I'nder favourable conditions of soil and climate pruning is less injurious than in the reverse case. On fertile fresh soil a comparatively small root system suffices to fulfil the necessary work of assimilation, and fresh organs are formed in a short time ; on dry poor soil pruning of the roots must be much more restricted. il. Mdiiinr of Viuninij. In all cases a clean cut should l)e made ; it should be some- what slanting and not at right angles to the branch or root. Where a whole branch is taken off, the cut should be Husli with the stem to insure quick healing by occlusion ; if it is only shortened, the cut should be made just above a strong bud. The operation may be performed with a pruning knife, pruning scissors, shears, or a light hatchet ; in the latter case the plant should be placed on a firm support during the operation, so as to injure the remaining wood and bark as little as possible. 11. Protection of Pldiita in Traitsit. During transit plants must be protected against drying u[t and frost, and this refers more particularly to the root system; a few minutes of exposure often suffices to kill the liner roots. The method of protection depends on the kind of plants, the time during which the plants are in transit, the species, and tlie climate to which they are exposed ; the drier the latter, the more carefully must the plants hv. protected. PROTECTION OF PLANTS IN TRANSIT. 189 Ball plants possess already a good protection in the lump of earth in which the roots are imbedded. For transport occupying not more than one day the balls should be packed close together to prevent their drying up and the earth from l)eing shaken off. Only in rare cases are such plants carried over long distances, the cost being too great. Plants without a ball of earth should be at once protected. This is best done by dipping the roots immediately after lifting into soft mud, which forms a thin layer over them ; the plants should then be tied together in bundles of convenient size. For transport over short distances, which occupies not more than one day, the bundles should be placed in baskets, wheel- barrows, carts or waggons, according to circumstances, the roots being surrounded by, or imbedded in, moss, grass, or earth. If the weather is dry and the sun shining, some cover may also be provided, to prevent the drying up of the foliage. The moss or grass used to cover them should be moistened, and this process may be repeated from time to time during transit. If the transport extends over several days, further precau- tions are necessary. The small bundles are, in that case, bound together into large packages, by arranging the plants so that the roots are all on one end, well wrapped in wet moss, grass, &c., and then secured by withes. The whole package is covered with matting. In the case of small or middle-sized plants two layers are packed together with the roots in the centre and the crowns outwards on both sides. Plants packed in this manner keep fresh for a week, provided they are so packed that no heating takes place. On arrival at their destination the plants should be at once unpacked, and either planted out, or heeled in (bedded in earth) until they can be planted. The imbedding is best done by arranging the small bundles in trenches and covering the roots and part of the stem with moist soil. If necessary, shelter against the sun or dry winds may also be provided, and the plants may be watered. I '.to AirriFlCIAI, FOiniATlON OF WOODS. 12. I'njiarKtioii of tlir Snil. Only ill very rare cases does the soil require complete workiiif,' before planting, and in such cases it is done by one of the methods indicated for direct sowing. As a general rule planting requires only working at the spots where the plants are inserted into the ground, or none at all. In sylvicultural operations conducted on a large scale the worked area of a planting spot ranges upwards from a few square inches, and rarely exceeds 2 or 3 square feet. The actual method of working the soil depends on the methods of planting ; hence it will be described when dealing with the latter. B. Raising Plants. Plants can be procured either by purchase or home produc- tion ; in the latter case they can be taken from existing woods, or raised in temporary or permanent nurseries. Although in the majority of cases plants are purchased or produced in home nurseries, the third method may in certain cases be admissible, hence the subject will be divided as follows : — (1.) Purchase of plants. (2.) Plants taken from existing woods. (3.) liaising plants in nurseries. 1. Purchase of Pl<()its. In former times the necessary plants were, as a general rule, grown at home, and this is still the case in many countries. In Great Britain, and latterly also on the Continent, a highly developed industry of raising plants for sale has been estab- lished, and in the former country by far the majority of plants are now-a-days purchased from nurserymen. This system is very convenient, since the planting operations are not inter- fered with by want of tlie necessary planting material. Pail- way communication, also, is now so extended and rapid that most imi)ortHnt s[)ecies of forest plants can be sent to any PURCHASE OF PLANTS. 191 part of the country without serious risk to their health and vigour. The art of raising strong hardy plants has heen so fully developed hy nurserymen, that almost any description of plants is procurable at short notice. Under these circumstances the purchase of plants is quite justified in Great Britain and in a few other countries, provided the forester takes care that he receives only good healthy plants of the description indicated on page 171. He must, more especially, see that he receives plants with a properly developed root system — that is to say, one which is full and compact, but at the same time of a natural shape. It has of late years become the practice to lay down the seedlings, when they are pricked out, into shallow trenches, involving the bending over of the root system to one side ; the result is a bushy root system altogether lop-sided. If such plants are put out into the forest, they take years to recover a normal, healthy shape of the root system, and until this takes place they have only a limited hold on the ground, and are liable to be blown over by strong winds. This drawback is often maintained up to middle age, if not longer. Unless nurserymen give up that vicious practice, they must be prepared to see landed proprietors revert to the system of home nurseries. In selecting plants care should be taken that they are suited to the locality where they are to be planted. For fertile locali- ties at low elevations well grown tall plants are desirable ; for poor soil, especially at high elevations, short sturdy plants are preferable. It is generally considered best, if no great diffe- rences exist between the soil and climate of the nurser}^ and of the locality where the plants are to be put out. 2. Plants taken from existing Woods. Where operations are conducted on a small scale, and nursery plants are not available, the planting material may be obtained from existing young woods, such as natural ]'M AllTIl'K'IAL FORMATION OF WOODS. reji;enerations or sowings. In such cases the plants are taken from the parts which are too thickly stocked, and consequently they are g(!nerally indifferently developed ; they are frequently slow in coniiiiL,' on after transplantin;^^ and rarely yield <^ood results. ;i. lulis'in;! Phiiits in XiirHcrics. Where plantings are conducted regularly on a large scale, plants may he raised in home nurseries; and even if the plants are purchased from nurserymen, it is desirable to have an auxiliary nursery at home ; hence it is necessary to describe here, in outline, the establishment and management of nurseries. Nurseries may be temporary or permanent ; the former are used for a few 3'ears onl}', generally to yield the material for the planting of a particular locality, when they are abandoned and a new nursery laid out elsewhere ; permanent nurseries are used for a long series of years. Each has its advantages and disadvantages. In the case of temporary or shifting nurseries the cost of transport and the risk of damaging the plants during transit are smaller ; on the other hand the cost of laying out is greater, as it recurs every two or three years, and they do not, as a rule, yield eijually good plants. Tem- porary nurseries can be established in localities of the same description as those where the planting has to be done ; hence they may be desirable where distinct zones of vegetation occur, especially in mountainous districts, also where the plants are to be put out with balls. Permanent nurseries require to be manured from time to time, but they yield better plants ; they are preferable in the majority of cases, especially in more level districts, where large numbers of plants are required year after year, and where the transport is fairly easy and cheap. There is l)ractically no ditference in the treatment of temporary and pernuinent nurseries, except that in the latter case all arrangenunits are of a more lastiiit/ nature. RAISING PLANTS IN NUKSERIES. 19:3 a. Clioicp of Site. The site should be favourable for the growth of the particular kinds of plants which are required. If only one species or a few of similar requirements are wanted, a site can be chosen which agrees with their special requirements as regards soil and situation. In the majority of cases, however, plants of differing requirements are to be raised, and it is there- fore best to choose a site of average conditions. The most suitable soil is a light or sandy loam. Heavy clay should be avoided, as it is less suitable than even a light sandy soil. Good depth is essential, as it insures a more even degree of moisture. As regards situation, the site should, if possible, be in the centre of the area where the planting has to be done ; but if no suitable locality is there available, it is better to go to a moderate distance in search of it. The site should be accessible and easy of control. A gentle slope is best, or an elevated level plain ; in either case it should not be exposed to danger from frost, especially late spring frost, fairly sheltered, but open to the free circulation of air. The aspect depends on circumstances, especially latitude and elevation. In temperate Europe the least favourable aspects are probably an eastern or south-eastern (on account of late frosts) and a southern or south-western (on account of the rapid evaporation of moisture). The site should, if possible, be so chosen, that water can be led on to it from a spring or stream, or that at any rate water may be found at a reasonable depth for the construction of a well. h. Area. This depends on the species, the method of treatment, the number of plants, whether they are pricked out or not, and the age at which they are finally removed. It is clear that no general rule can be given. By way of illustration it may be mentioned that for raising two-year-old seedlings of Scotch s. o 194- AltTIFU'IAL FOHMATION OF WOODS. pine or spruce, the area of the nursery should l)e about ^ per cent, of the area to be annually planted at 4 feet apart ; if the two-year-old seedlings are pricked out, and remain for another two years, the nursery should conii)i-ise at least 4 per cent of the area to be planted annually. Where broad leaved species are raised, such as oak or beech, the percentage is higher. It increases very rapidly with the age of the plants ; for instance in the case of twice pricked out oaks, which are planted out at the age of 9 j'ears at 10 feet apart, the area would amount to not less than 30 per cent, of the area to be planted annually. r. Shapr. "Whenever a free choice is possible, the shape of the nursery should be that of a square or rectangle, because it admits of a regular rectangular shape being given to the seed beds witliout waste of area. '!, » Larch . = •4() ,, Austrian pine . ~ -20 Broadcast sowing takes from twice to four times the quantity of seed required for drill sowing ; hence Gayer's data for conifers agree fairly well with those given l)y Messrs. Howden ^: Co. /. Fr id' in II auf. In some cases the seedlings are taken direct from the seed bed to the forest ; in others they are transplanted once or several times in tlie nursery before they are finally put out. British foresters call the former " seedling plants," and the latter " transplants." Seedling plants which are to go direct to the forest must be grown roomy in the seed beds, so that they may develop properly; plants which are to be pricked out in the nursery may stand closer together in the seed beds. Pricked-out plants are generally placed in rows, called " nursery lines." The soil devoted to them must be carefully , RAISING PLANTS IN NURSERIES. 20^5 prepared, though not perhaps quite to the same extent as that of seed beds. The area required for nurser}- Hues depends on the species, the age of the seedhngs when pricked out, and the time the}'' are to remain in the nursery ; on an average it may be estimated at 8 to 10 times the area of the seed beds, provided the plants are one year old when pricked out, and four years old when put out into the forest. Seedlings should be pricked out while young. In the tropics the proper age is sometimes only a few weeks ; in temperate Europe generally one or two years, according to the nature of the species and the locality. When the object is to produce large and strong plants, or a full and bushy root system, they may be pricked out a second or even a third time, after an interval each time of one, two or more years. • Plants may be pricked out at any time, provided it is done carefull,y, rapidly, and when the soil is fairly moist. In temperate Europe the best time for extensive operations is early spring. Moist weather is desirable during the operation, else the plants may have to be watered. The lifting and protection of the plants during transit have been dealt with above (pages 183 and 188). The distance between the nursery lines and between the plants in the lines depends on the size of the plants, their more or less rapid development, and the time which they are to remain in the lines. Ordinary two-year-old seedlings of Scotch pine and spruce, which are to remain for two years in the lines, may be placed from 3 to 6 inches apart in the lines, with a distance of 8 to 12 inches between the lines. Larch plants must be placed somewhat further apart, while for oak the distances are still greater. Brown, in " The Forester," recommends the following distances : — One- or two-year-old seedlings of oak, ash, elm, and beech, 4 inches apart in the lines, the latter being 24 inches apart. 204 ARTIFICIAr, K(>1;M AIION OK WOODS. Oiie-vciir-ol.l liircli siH'dlin^'s . = IC. x 2.1 iiidics. Two-yciU--ol(l larch seedlings. = IS x :{ One- or two-year-old Scotch pine seedlings . . . = 14 x '2 ,, ^[essrs. Howden c*c Co., Inverness, generally line out the larch one year old and Scotch pine two years old. They place them 8 inches apart in the lines, with 1) inches hetween every two lines. The pricking out can he done in a variety of ways according to the description of plants. The more usual methods are, either to make a separate hole for each plant with a planting peg, a small hoe, or a garden trowel, or to open trenches, Fi- ^:5. into which the i)lants are placed at the proper distance apart. In either ease the roots should he placed into a natural position, and the soil well pressed around them. British nurserymen, in raising plants for sylvicultural purposes, proceed in the following manner: — The soil, after having been brought into a suitable condition, is thoroughly smoothed along the whole length of the conrart- ment, then a planting line is placed on it, parallel to one side of the compartment ; then the ground is cut away with a spade along the line, so that a shallow trench is formed with one side almost vertical (Fig. n;}, a). Against this side the plants are placed at the proper distance apart, some earth pressed around them, then the trench completely filled up, the earth pressed down once more with the foot, and the whohi smoothed over (Fig. 58, I/}. Tlieii the i)laiitiiig line is moved RAISING PLANTS IN NURSERIES. 205 on to the following row and the operation repeated. The method works very expeditiously, and it is an excellent one in principle. It has, however, become the practice to make the trenches so shallow, that the root system of the plants, instead of assuming a natural position in the ground, is altogether bent to one side. The result is that the plants develop a lop- sided root system. It may be easier to put out such plants, besides saving expense, but the system is certainly not favour- able to the development and stability of the trees grown from them. The author has observed, that in many cases trees 30 to -10 years old had not yet established a normal root system, and that numerous trees are blown down for this very reason. To produce really good plants, the vertical side of the trench should not be less than 10 inches deep, so thai the roots go down straight to that distance (see Fig. 54). The additional expenditure is not more than about one shilling per 1,000 plants, III. Choice between Secdlbui Phaih and Transplants. Each of these two kinds of plants has certain advantages and drawbacks, and it depends on the circumstances of each particular case whether the one or other is preferable. Seedling plants are considerably cheaper than transplants, as the latter require a larger area, as well as labour in pricking out and tending. On the other hand transplants are much superior, as they have more room to develop ; especially the root system becomes fuller, more bushy and compact. 206 ARTIFICIAL FOHMATION OF WOODS. For plantinj]; in favourable localities seedling plants may do as well as transplants ; in unfavourable localities the latter are preferable ; also when specially larn;e plants are required. The choice also depends on tlie species. In the case of Scotch pine and oak seedlinjj; plants give good results ; in that of most other species transplants are to be preferred. A plan sometimes followed consists in classifying the seedling plants when, say, two years old. The best plants are put out directly into the forest, the second class plants are pricked out in the nursery, and the third class, com})rising the weak and misshapen plants, are thrown aw'ay. //. Ti'inliiKj Seed Beds and Nurscrij Lini's. The seeds, as well as the young plants, require a certain amount of tending, more especially protection against injurious influences. The details of such tending and protecting are given under the head of Forest Protection, In this place only the more important measures directly connected with nursery work will be indicated. (1.) The seeds must be protected against birds. These may be kept off by shooting or frightening. If this is impracticable, small seeds may receive a coating of red lead, or the beds may be protected by placing on them thorny brushwood, branches of coniferous trees, grass, etc., or nets may be spread over them, resting on supports, so as to keep them at a suitable distance from the ground. 'J'he latter have tbe disadvantage that they must be lifted when weeding has to be done. Wire netting, beiil in a semicircle over tlie seed beds, is most suit- able ; it needs little sui)[)ort and lasts many years. Mice, moles and mole crickets often do much damage ; they must be caught or poisoned. Mice may be caught in pots buried in llu; i)alhways and half tilled with water ; these animals are in tbe halul of running heedlessly along the paths, when tliey fall inl(^ the pots. RAISING PLANTS IN NURSERIES. 207 Earthworms do damage by dragging small seedlings into their burrows. Hares, rabbits, etc., must be kept out by fencing with wire netting. Squirrels must be shot. Amongst insects, the cockchafer larvae and the wireworms are the most destructive in temperate Europe. In both cases damage is difficult to prevent. Cockchafers are specially fond of laying eggs in clearings in the forest, such as a nursery ; and if this be repeated once or twice, it may be necessary to change the site of the nursery. Almost the only way to meet the damage in the case of grubs of the cockchafer and the wireworm is to collect them, or to kill them with gas lime. (2.) Extremes of climate make themselves felt by frost or drought. In the first place a considerable fall of temperature inter- feres with the proper germination of the seeds, and it may injure young seedlings. Such damage is prevented by cover- ing the seed beds with moss, grass, straw, needles, or short branches of conifers, or by erecting a temporary roof at a con- venient height over the seed beds. Very delicate seedlings may be raised under glass. The covering should be removed during the day and replaced in the evening. Somewhat later on, alternate freezing and thawing may lift the young plants out of the ground ; this can be prevented by covering the space between the lines with moss or sawdust, or by heaping earth on to the plants. If, nevertheless, it should occur, the plants must be speedily put back into the ground. Damage by drought is prevented somewhat in the same way as that by frost, best by shades, which are placed over- head, or on the sunny side of the beds. If the dry weather should last for some time, the beds may have to be watered. This, if once commenced, must be continued until rain falls. As watering is expensive, unless it can be done by irrigation with water obtained from a higher point, it is only done when absolutely necessary. Many British nurserymen never water ; tliey prefer taking their chance. In more southern countries 2(IS AKTIFIC'IAI. FOI'.MATION OF W()f>I)S, waterinp; frequently l)ecomes a necessity. There, also, protec- tion u^'ainst hot winds is frequently given by shades placed on the side whence the wind blows. (3.) Weeding should be done frequently and thoroughly. It can be done by hand, or with knives, weeding forks (Fig. 55), light two- or three-pronged hoes, the Dutch lioe (Fig. 56), etc.* The weeding is generally accompanied by some loosening of the surface soil ; but apart from weeding, periodical working of the soil between the nursery lines is highly beneficial. (4.) If the seedlings come up too thick in the seed-beds. Fi-,'. .55. Fig. o6. they may be thinned out. In doing tliis, care must be taken not to disturb the plants which are to remain ; hence the best plan is to cut off the weakest plants close to the ground with scissors. C. — Methods of Planting. The most important point in planting is to reduce the interruption of growth to a minimum, so that the plants may quickly estal)lish themselves in their new home. How this object can be realised depends on the description of the plants, their size, and the conditions of soil iuid cliniate. To meet the • Figs. .1 .-Hi liave Imcii tak.'ii fnun r.iM.lcs Cc Illus itc'LANTlNG WITH PEG OR STAFF. 2i5 it is frequently necessary to work the soil before planting, either entirely, or in strips or patches. This can be done Fig. 65. with a light plough or the hoe. In such cases the area may be used for the raising of a field crop before planting. Pegs of various shapes are used, such as the ordinary planting pegs (Fig. 62), the planting dagger (Fig. 63), Buttlar's iron (Fig. 64), etc. The planting peg is constructed of wood ; Fig. 63 consists of a wooden peg with an iron coating up to the handle ; Buttlar's tool is made entirely of iron, the handle being covered with leather ; it weighs about seven pounds. When using any of these tools the planter holds a bundle of plants in one hand and the tool in the other ; he inserts the tool into the ground (Fig. 65, a), takes a plant out of the bundle, holds it between two fingers, withdraws the tool, inserts the plant into the hole, re-inserts the tool in a slanting position (Fig. 65, h), and presses earth on to the plant by push- ing the peg towards it. The second hole thus produced (Fig. 65, c), can be filled up by inserting the tool a third time, or by pressing earth into it with the foot. 216 ARTIFICIAL FORMATION OF WOODS. In these plantings the root should go down straiglit into the hole, and not be doubled up. To facilitate the operation of insertion, and to protect the fine roots against drying, they are frequently dipped into soft mud as soon as they have been lifted. The method is cheap and of great despatch, especially if it is not necessary to work the soil beforehand. It is specially adapted for light sandy soil, less for stiff soil, or for a locality %d Fi-. G'J. which is likely to be overrun by weeds. The plants should not be more than two years old, or else they will have developed too long side roots. Only seedling plants should be thus planted. Where deeper holes are required, or on slony soil, the planting staff (Fig. GO) may be used. It is a muc-li heavier tool, weighing about eleven i)ounds, and two men, or a man and a boy, are required for the operation, one making the holes and tlie oilier insert ing iliu i)Ianis. PLANTING : NOTCHING. 217 r. JVo/c/ri/if/. This method differs from planting with a peg in the shape of the planting hole, which is that of a notch. The tools ordinarily used are the planting hatchet (Fig. 67), the notching spade (Fig. 68), and the ordinary spade. The hatchet is inserted into the ground with one hand and pulled out again, thus producing a notch, in which the plant is inserted ; the Fig. 70. Fig. 71. notch is closed by knocking the adjoining earth into it with the thick end of the hatchet ; finally the soil is pressed down with the feet. The notching spade is wedge-shaped, and after insertion into the ground an enlarged notch (Fig. 69) may be produced by swaying the spade to and fro. The tool requires two persons, one making the notches, and the other inserting the plants, filling in, and pressing down the earth with his feet. The common spade can be used in the same way as the notching spade, but a much better shape is that exhibited in 218 Airni-UIAL roKMATiON OF WOODS. Fig. 70 {a, b). It is perfectly straight, willi a sharp ^xjiiil which easily penetrates into tlie soil. In using this spade the notch generally has the shape shown in Fig. 70 (c) (exaggerated). The plant, after insertion into the notch, is securely fixed in the ground as indicated in the case of planting with the peg (Fig. Go). This spade is no douht the hest tool for notching which has heen constructed. On stiff soil the holes for seedling plants may be made with a hollow spade, like Fig. 71. It is not necessary to remove the ball of earth from the spade by hand ; by inserting the spade for the purpose of making a second hole, the ball of earth taken from the previous hole is ejected at the top, and can be used to fill up the hole afterwards. The plant is inserted as before, and the hole is filled up and the soil pressed down firmly by means of a peg and the feet. ^ d^__^ ^^^_j| ^ V -' /::=- Fiir. 72. In Great Britain notching is done in a somewhat different way, generally with the ordinary spade, so as to i)roduce a T-shaped or a triangular notch, mostly the former. The spade is inserted into the ground (Fig. 72, a), and withdrawn ; then it is a second time inserted at light angles to the first insertion and at one end of it (Fig. 72, h) ; next the handle is bent backwards, thus raising and opening out the edges of the first notch (Fig. 7*2, r) ; then the plant is slipped in fiom the MOUND PLANTING. 219 blade of the spade towards the far end of the first notch, the spade withdrawn and the soil pressed down with the feet, so as to cause the notches to close completely. The operation requires two persons, a man and a boy. The merits of ordinary notching are very much the same as planting with a peg. As regards the British method of notching it must be noted that the root system obtains an altogether unnatural position, it being completely pressed to one side (compare Fig. 53, h, on page 204). It has already been pointed out in that place, that often many years pass before this drawback is overcome. The system as practised in Britain can yield satisfactory results only under a favour- able climate and in the case of certain species. It is chiefly employed in planting Scotch pine and larch plants two to four years old. 3. Mound Planting. Apart from wet and swampy localities, planting is sometimes done on mounds, instead of in pits. The mounds are formed either by scraping together the ordinary soil, or by depositing a basketful of specially prepared soil at regular intervals. The plant is inserted into an opening produced in the centre of the mound, and then the soil pressed round the roots until the mound has been ^in- 73. re-formed. Finally the mound is, whenever practicable, covered with turf, to protect it against rapid drying. For this purpose two pieces of turf are placed, one on the shady side [a), and the other on the sunny side (h), so that the latter overlaps the former (Fig. 73). In the absence of tarf, stones may be placed on the mound. The method is only suited to plants with a shallow root system, if the mounds are to be of moderate size. It has yielded good results on soil, such as gravel or hard clay. :l-20 ARTIFICIAL FORMATION OF WOODS. where the striking of tlio plants under orJuiary pliintin<^ would have heen douhtful. The expenses are higher than in the case of pit planting, but not by very much, since the method contemplates only small mounds. Where mound planting is adopted against an excessive degree of moisture in the soil, the mounds must be consider- ably higher and larger than in the method just desscribed. The expenditure is further increased if the planting is done on continuous ridges, prepared as described on page 137. D. Planting of Slips, Layers and Suckers. Plants of these kinds are used in the case of species which do not readily seed, or the seed of which germinates indiffer- ently, or for the purpose of obtaining at once plants of some size. Such methods are only auxiliary in temperate Europe, except in the case of willows and poplars. 1. Slips. A slip or a cutting is a rootless plant, which consists of a piece of young green wood taken from the stem or a branch of a rooted plant ; when inserted into the ground it develops roots and crown. Poplars and willows are grown in this way. Slips may retain the leading shoot or be truncated. The former consist as a rule of stool shoots ; the latter can be taken from stool shoots or from the branches of older trees, their length differing from a few inches up to ten or more feet. In some cases slips are in the first instance placed into nurseries until they have become rooted, but they are gener- ally planted out at once in the forest. The insertion into the ground can be done in various ways, such as placing the slips ill furrows and covering llicni by drawing a second furrow witli the plough ; or they may be placed in ditches, trendies, l)its, or each slip simply pushed into the ground to the required ilepth. PLANTING SLIPS, LAYERS AND SUCKERS. 221 When entire slips are used, onl}' the lower portion is inserted into the ground ; of truncated slips only a small part remains above the surface. In order to insure striking and a proper development, the ends of the slips should be cut sharply- and smoothly in a slanting direction, and each truncated slip must contain some buds, of which at least one, or better several, must be above ground. It is also essential that the bark should not be injured at the ends; hence pushing the slips into the ground without a previous opening is only admissible in very loose soil ; in all other cases they should be planted with a special iron dibble. The best time for planting slips is early spring, shortly Fig. 74. before the buds begin to swell, though, under favourable circum- stances, the slips can be planted at other times, even during the growing season. The roots formed after planting come from the callus produced at the lower end or from the lenticels in the bark. In England the stools of osiers are recruited by slips, which are mostly entire ; they are planted immediately after the osiers have been cut, usually in December. On the Continent truncated slips are used in preference. 2. Layers. Layers are branches, or stool shoots, which have been bent down and partly buried in the soil ; they develop roots at the buried portion, and when this has taken place, they are severed 222 ARTIFICIAL FORMATION OF WOODS. from the mother tree and represent independent plants ready to be put out. The formation of roots may be expedited l)y removing some of the ])ark of the layer below ^M-ound on the side of the parent tree. Where large numbers of layers are required, the most suit- able plan is to produce stools wliich send out numerous shoots. Each of these shoots is then bent back and fastened into tlie ground, where it remains until rooted (Fig. 74). In England lime and elm are generally propagated in this manner. 3. Siirhrrs. The root from which the sucker has sprung is cut through, clean and slanting, on both sides of the base of the sucker, the latter lifted out of the ground and put out into the forest. The method is rarely used, as disease is likely to be introduced through the cut ends of the root. In some cases pieces of roots are planted out, which produce roots and shoots. Note. — Grafting and Budding, being outside practical sylvi- culture, will not be dealt with in this volume. 223 CHAPTER III. NATURAL REGENERATION OF WOODS. Natural regeneration can take place by seed, or by shoots and suckers. Accordingly the subject divides itself naturally into two parts. Regeneration by seed is applicable to all species ; that by shoots and suckers applies only to broad leaved species, since the power of reproduction of conifers by shoots is either absent altogether, or at any rate so feeble that it is useless for sylvicultural purposes. Section I. — Natural Eegeneration by Seed. By natural regeneration by seed is understood the formation of a new wood by the natural fall of seed, which germinates and develops into a crop of seedlings. The trees which yield the seed are called the mother trees ; they may stand either on the area which is to be re-stocked, or on adjoining ground. Accordingly a distinction is made between — (A.) Natural regeneration under shelter- woods ; (B.) ,, ,, from adjoining woods. A. Natural Regeneration under Shelter-woods. The area is stocked with seed bearing trees, and the new generation springs up under their shelter ; for some time, at any rate, the area bears the new crop and part of the old one. The system is that which occurs in primeval forests. When a tree falls from old age, or other cause, and an opening is thus formed in the cover overhead, the seeds falling from the adjoining trees germinate and develop into seedlings ; these grow up under the shelter of the older trees, until they in their turn become mother and shelter trees. In this manner 221 NATIRAL HKdKNEHATION (>F WOODS. primeval forest, if undisturbed, goes on regenerating itself for generations. The process is a slow one, as the young crop will only develop when sufficient light is admitted by the fall or death of the old trees. In sylviculture it is accelerated by the artilicial removal of a portion of the old trees, when they have become lit for economic purposes. By degrees, modifi- cations have been introduced, which lead to a number of distinct methods. Of these, the following demand special notice : — (1.) The Scleriiiiii Si/stciii.*— The age classes are evenly, or approximately evenly, distributed over the whole area of the forest. Throughout its entire extent the oldest, largest, and diseased or defective trees are year after year, or periodically, removed, followed b}^ the springing up of new growth in small patches or single trees. (2.) The Group Si/steni. — The age classes are distributed over the forest in groups of moderate extent. The oldest groups are regenerated first, then the next oldest, and so on, until the whole forest has been gone over. Some modifications of this system have been introduced, which will be explained further on. (3.) The Compartment Si/stem.*^ — The age classes are so far separated, that each occupies a distinct portion of the area, representing an even aged, or approximately even aged, wood. Each wood comprises one or moie compartments, and either the whole, or one compartment at a time, is regenerated uniforml}' over the area, so that tlie old crop is re})laced by a young, fairly even aged wood. (4.) The Strip Si/strm. — This is a modification of the com- partment system, each compartment being divided into a number of strips. As it differs from the compartment system in some respects, it will be dealt with separately, * The term selection syxtnn was intiodiicoil in India ; it is perhaps not an ideal term, since a certain amount of selection is practised in all systems; it has been retained, as none better is at jirescnt available. The system is called Frmrlbetrieb, or Pldnterhetrielj, in (Jcrman. and Jurdimige in French. f Sehlfif/ireiner Jietrieh in (icruian, and mithode jmv eouprx mcrots) vex in French. THE COMPAETMENT SYSTEM. 225 The limits between the several systems are not alwa3's clearly defined, as will be seen further on, but there are certain general conditions of success which hold good for all. Amongst these the following may be mentioned : — (1.) The mother trees must be capable of producing good seed in sufficient quantity. (2.) The soil must be in such a condition that it forms a good germinating bed. (3.) The young seedlings must have sufficient light to grow up, and yet, if tender, they must be protected against external injurious influences. (4.) The fertility of the locality must be duly preserved by protecting the soil against the sun and air currents. These conditions, if not naturally existing, must be produced l)y timely and judicious interference. The measures adopted for the purpose consist in — («.) Cuttings so executed that they produce the desired conditions. {J>.) Artificial preparation of the germinating bed, if this should he necessary. The several systems comply with these conditions in varying degrees. In order to bring out the general character- istics of the methods, it is desirable to commence with a description of the compartment system. 1. Tite Comj)artment or Uniform System of Natural Rer/eneration under SJielter-woods. The regeneration occurs approximately at the same time and uniformly over a whole wood, which, for convenience' sake, is here called a compartment. The area treated at one time and in a uniform way is called the regeneration area. The new crop should be created, if possible, by one seed year over the whole regeneration area ; this, however, succeeds only in exceptional cases, so that, as a rule, two or even more seed years are required to complete the regeneration. As a consequence the regeneration process may extend over a •226 NATrKAI. HEOENKRATION OF WOODS. term of ;"). 10. 15, iuid sometimes even more years, resulting' in a new croj) wliich is only approximately even aged. The euttiii<;s are made from time to time as required, and so tliJit the old or shelter- wood gradually makes way for, and is replaced hy, the new crop, the process heing as uniform as practicable over the whole regeneration area. These successive cuttings are, for convenience' sake, generally arranged into three groups, each of which represents a distinct stage, namely, — (a.) The preparatory stage. (h.) The seeding stage. (r.) The final stage. Theoretically speaking, the preparatory and final stages each comprise several cuttings, and the seeding stage only one, but their actual number depends on the circumstances of each case, as will be seen from the description given Ijelow. /'. /'i/'/it/n//or// Slatjf. There is a time in the life of every wood which is most favourable for natural regeneration ; it occurs during the period of maturity, but differs somewhat in accordance with the special conditions of each wood. That time is, theoretically speaking, the best for the process of regeneration, but other important considerations may not always permit of this particular period being taken advantage of. Only in rare cases have the trees at that time reached a profitable size for economic purposes ; hence, they must be allowed to grow on for a series of years, and thus pass the most favourable period. In other cases, where only small material is required, the objects of management may demand cutting over before the most favourable period for regeneration has been reached. Pi very such deviation ci-eates obstacles to successful regenera- tion. Either the trees are not in the best period of life for the production of good seed in sufficient quantity, or the soil is not in the best possible condition to serve as a germinating bed. It is the object of the pnparatori/ riittiii;is to counteract THE COMPARTMENT SYSTEM. 227 these and other drawl^acks, which require to he more fully explained. i. Preparation of a Suitable Seed Bed. The soil must he hrought into a condition which ensures a proper germination of the seed, and enahles the seedlings to reach the mineral soil with their rootlets within a reasonable time ; it must be suitably porous and moist. The necessary measures to ensure this depend on the condition of the wood, and on the nature of the locality. In the course of a rotation crowded woods produce con- siderable quantities of humus, which decomposes at a quicker or slower rate according to species and other circumstances. Where, on approaching the period of regeneration, the layer of humus and leaves is so thick that seedlings cannot reach the mineral soil w^ithin a few weeks after germination, it must be reduced before regeneration is attempted. This is done by removing some of the trees, and thus admitting the sun's rays and a more active circulation of air, which cause an accele- rated decomposition of the humus. The severity of the cutting depends on the original density of the leaf canopy ; dark cover overhead demands a heavy cutting, a thin cover a light cutting or none at all. It also depends on the nature of the soil ; over limestone the humus decomposes rapidly, on cold heavy soil slowly. Again, the leaves of some trees decompose more rapidly than those of others. Situation and the local climate must also be considered. Where the degree of moisture in the soil and the air is high, decomposition proceeds at a slow rate ; such localities are high situations, northern aspects, moist valleys, the shores of lakes and the sea. In all such cases the preparatory cuttings must be comparatively heavy. On the other hand, in localities which are liable to be overrun by a heavy crop of grass or weeds, the cuttings must be light, or else the young seedlings will be choked. Generally, the most suitable condition for germination has been reached when the covering of the soil has been so far q2 22S NATTRAL REGENERATION OF WOODS. reduced that the mineral soil can be seen hero and there through it, without bein^]; altof^'ether exposed ; the seedliiip;s will then be able to establish their rootlets in the mineral soil at an early stage, and thus escape the danger of being killed off by a subsequent spell of dry weather. Tf. at the conclusion of the preparatory stage, this condition h;is not been reached, a portion of the humus and leaves or moss may have to be removed artificially, or mixed with the mineral soil below. In many cases the vegetable covering of the soil has been already too much reduced by a premature interruption of the leaf canopy, so that the most favourable condition of the seed bed is past, the soil having becon^e hard and dry, or overrun by grass and weeds. In such cases further cuttings would only increase the evil, and must therefore be omitted ; a suit- able seed bed is in that case secured by working the soil immediately before or after the seed falls. The working of the soil may consist merely in removing the weed growtli, or in hoeing it up either entirely or in strips or patches, causing it to be broken up by pigs, raking, harrowing, or even ploughing it with a light forest plough. Generally speaking, this opera- tion is known as " ir<>undi)ifi the. soil,'' and is considered a most important cultural measure. At the same time it is expensive, and should be executed only when necessary. ii. Stukngthening ihe Shici;ieh Tiikes. After the ground has actually become stocked with seedlings, only a certain number of the trees, which formed the original wood, will remain on the ground to afford shelter to the young crop and the soil. If all the rest of the wood were removed at one cutting, so that the above-mentioned shelter trees were suddenly brought from a crowded into a comparatively open position, they would probably be thrown by the first gale. To avoid this they must be i)laced only gradually in a more open position, so as to obtain a firmer hold of the ground. This is done by the preparatory cuttings. The trees which are to form the ultimate shelter-wood must THE COMPARTMENT SYSTEM. ^29 be selected from the beginning ; they should be trees with neither exceptionally broadnor narrow crowns, but healthy trees with medium crowns, and these must be led over gradu- all}' from a crowded to a more open state. It follows that, from this ix)int of view, the preparatory cuttings are of more importance in the case of shallow-rooted species and very dense woods, than under opjjosite conditions. iii. Sti.mli.ai iN(i thii I'roductiox uv Sked. In some cases placing the trees in a more open position has a beneficial effect upon the production of seed, but this cannot be always relied on, as frequently such a measure is followed by increased production of wood instead of seed. iv. DlsTRIBUTIO.V OF THE YlELl). If forest trees were in the habit of producing seed regularly every year, arrangements might be made to place annually a suitable area into the seeding stage, and thus distribute the cuttings equally over successive years. As, however, most forest trees produce abundant seed only after irregular inter- vals, it is necessary to take full advantage of every such opportunity and then to bring as large an area as possible into the seeding stage. If no preparatory cuttings had been made, such a treatment would lead to an excessive yield in every seed year, and little or no yield in other years. Hence preparatory cuttings fulfil the further duty of assisting in the proper distribution of the yield. V. NUMBEIl .\.ND C'HAU.VlTEK OF CuTTINGS. Whether the preparatory stage should comprise one or several cuttings cannot be determined beforehand; it depends on the circumstances of each case. Sometimes such cuttings are altogether unnecessary or undesirable, in others one good cutting suffices, and in others again two or even more are required. The period over which the preparatory stage extends com- prises sometimes only one or a few years, at other times as 5i80 NATIHAI. UKCiKNKltATKtX OF \V()UJ)S. much as ten or even more years. In the hitter case the cut- tings should be light and freciuently repeated. Generally, the cover should not be interrupted to any considerable extent during the preparatory stage, except, perhaps, towards the end of it. In selecting the trees to l)e cut during this stage, a com- mencement is made by the removal of diseased trees, and all species not required or desired for reproduction ; then trees with bad crowns are chosen, followed by those with excep- tionally broad crowns, care being taken throughout that the trees destined for the ultimate shelter-wood are as evenly as possible distributed over the area, and give the shelter required for the species under regeneration. Ji. Sccdinij Sfaiio. If the process of preparatory cuttings has been allowed to take its regular course, it will result in the locality being graduall}^ brought into a condition fit to produce a new crop, which springs up and occupies the ground. Such is, however, rarely the case in practice, because the seed years come at irregular intervals ; hence, to avoid the risk of opening out the old wood too early, it is desirable to hold back a little with the preparatoiy cuttings. When a seed year actually comes, the regeneration area is frequently not quite ready for it, and it is found necessary to make an additional cutting, which is called the " seeding cnttinijy 13y this measure all trees are removed which are not required afterwards for shelter or the further production of seed. It is evident that the marking of the seeding cultin<,f should 1)0 made only when the seed is actually on the trees and sufticiently advanced to be depended on. The cutting can be made shortly before, during, or after the fall of the seed. Cases in which this rule may be departed from are compara- tively rare, for instance, on thoroughly fresh or moist soil, and in the case of a species which seeds regularly every year. The important question at this stage is the density of the THE COMPAKTMENT SYSTEM. ^3l shelter- wood which remains after the seeding cutting has been executed. That density must be such as to ensure the most favourable conditions for the further advancement of the 3^oung crop ; in other words, it must aft'ord sufficient light to the young crop without exposing it to injury by frost, drought, or excessive weed growth ; at the same time there must be sufficient shelter left to affect the general factors of the locality beneficially. It will be easily understood that, apart from the species, the density of the shelter- wood depends on a variety of circumstances, of which the following may be mentioned : — i. CuNDITIONS OF THE LOCALITY. The shelter-wood should afford protection against the drying up of the soil, frost, cold winds, growth of weeds, and perhaps also against damage by insects. In localities where the young crop is threatened by one or more of these dangers, the shelter-wood must be kept dark; amongst them may be mentioned poor, loose, stony soils, southerly and westerly aspects, steep slopes, localities exposed to dry or cold air currents or to great changes of temperature in spring result- ing in late frosts, those inclined to a strong growth of weeds, especially calcareous soils, where wind falls are apprehended, or where cockchafers and other insects are likely to settle. Where the opposite conditions prevail, in other words on generally favourable localities, the shelter- wood may be less dark, with a comparatively light cover overhead. ii. Condition of the Shelter-wood. Old trees have comparatively denser crowns than younger trees. Tall trees give less shade than short ones. Both circumstances must be considered in determining the number of trees to be left for the shelter- wood, so as to produce the desired density. iii. Degkee of Prepakation arrived at during the Preparatory Stage. The higher that degree, the lighter may be the shelter- wood, other conditions being the same. Whenever the preparation '2:iZ NATURAL HH(iENEUATK>N Ol" WOODS. has been insufficient or faulty, it is desirable to keep the shelter-wood comparatively dark, because the seeding maj' fail or be incomplete, so that a second seed year must be awaited before the area becomes completely stocked with a new crop. iv. Si'KciKs. Above all, the nature of the species determines the density of the shelter-wood. Tender species, especially those of slow growth during youth, require a dark shelter-wood ; hardy, light-demanding, quick-growing species a much lighter one. In the case of the latter, the distance of the shelter trees may be governed only by the distance to which the seed is naturally disseminated. V. t;i;NKi;Ai,i.Y. The cover of the shelter-wood should be as even as possible throughout whenever the conditions are uniform over the whole regeneration area ; if they differ from i)lace to place, the shelter-wood must be arranged so as to suit the changes. Along the edges of the wood, especially where exposed to dry, cold, 01- strong air currents, the shelter-wood should be kept dark, and it may be even necessary to provide beforehand a special shelter belt. As already indicated, the shelter-wood should consist of healthy trees with moderate-sized elevated crowns. If trees with low crowns have to be selected, it is useful to prune the lower branches away to a height of 15 — '10 feet. The time for making the seeding cutting may be, as stated above, shortly before, during, or after the fall of the seed ; it must be concluded and all the material removed before the seed begins to germinate. In felling the trees care must be taken not to hijure those which remain as the shelter-wood. The proper time has now arrived for considering whether any artificial working of tlie soil is required. Should this be the case, it can be done as indicated on page 158. Where root wood is saleable and the removal of the stools desirable • )n other grounds, the trees conipiised in the seeding cutthig THE COMPARTMENT SYSTEM. 233 may be grubbed out, thus ensuring a considerable amount of working of the soil. If the working of the soil is done after the seed has actually fallen, the latter is thereby brought into the ground. The depth of such working depends on the natm-e of the seed ; it may be deeper for large seed, such as acorns, beechnuts, and chestnuts, but it must be shallow for small seeds. At this period the question what to do with any advance growth must also be decided. Many foresters clear it away, so that the young crop may be as uniform as possible ; others leave really heallliy groups of it to form part of the new wood; ordinary underwood of other species must be removed. From this time forward the regeneration area must be carefully protected against the removal of litter, cattle grazing, and grass cutting. f. Final Shige. The final staye comprises the period from the execution of the seeding cutting until the ultimate removal of the shelter- wood. The principal objects of the shelter-wood, after the ground has been stocked with a crop of seedlings, are to protect the young growth against various dangers and to preserve tbe activity of the soil until the new' crop can undertake that duty. At the same time the shelter-wood will act obstructively as regards the admission of light and precipitations, and therefore it must not be left longer than is actually required. Its removal is effected, so as to meet these various requirements, by one or several successive cuttings executed at intervals of one, two, or more years. The rate at which, or the time within which, the removal takes place depends on various considerations, such as the following: — i. Activity of the Soil. The preservation of a suitable degree of moisture in the soil is of first importance. Owing to the action taken during the preparatory- stage, the degree of moisture in the soil may have ■i'-U NATURAL KKdENKHATloN OK \VO()J>S. been iinj)eiille(l. From tlie moment tliat a new crop lias actually sprung up, the considerations which prompted the measures taken during the preliminary stage disappear ; it becomes the duty of the forester to do his utmost to give to tlie soil all the slielter available after due consideration of the reijuirements of the young crop, and to re-establish as quickh' as possible a fresh and substantial layer of humus on the ground. Until the new crop closes overhead, therefore, the old wood must provide a certain amount of shelter, and the leaves falling from it will form the nucleus of the new soil covering. On steep slopes the remaining shelter trees help also to prevent damage by water rushing down the hill side. At the same time the cover of the shelter -wood during the final stage is already much interrupted, and not too much must be expected from it ; in some cases it may even act injuriously, as it may deprive the soil of more rainwater and dew than is preserved by the beneficial action of the crowns of the trees. ii. FliusT. As regards frost, the shelter-wood does good service In- reducing radiation ; it is less effective against cold air currents, unless it is supplemented by a dense shelter belt or wind break along the edges of the wood. Most species are liable to be injured by frost during early youth, and some require protection against it for a consideral)le numl)er of years. iii. W'l-.Ki.s. Here again tlie shelter-wood acts beneficially, l)y preventing, or at any rate retarding, the springing up of weeds, thus giving time to the new croj) to increase in height before it has to contend with them. iv. Inskits. Experience has shown that damage by insects is in many cases less pronounced under a shelter-wood than on clear cuttinitribtttion of tJtc i/icUl over the several 3'ears and the state of the market frequently interfere with the timely execu- tion of the cuttings. Similarh', the occurrence of a seed year may necessitate a suspension of cuttings in the areas stand- ing in the final stage. These matters are not conducive to a healthy development of the young crop, but the drawback is to some extent compensated by the heavy increment laid on by the shelter trees, which increase rapidly in size and value. The absolute d it ration of' tin- final stiKjc differs considerably according to species tUid the special conditions of each locality. In the case of some light-demanding hardy species, and in favourable localities, it may not be longer than from three to five years, while it may extend over 10, 15, and even more years in the case of tender species, in unfavourable localities, and where the object is to increase the size and value of the shelter trees in their ro(miy i)osition. In executing the fellings in this stage special care must be taken to avoid injuring the young growth. The trees raustl)e lopped, if necessary, before felling, and they must be thrown in that direction in which they are likely to do least damage. Fellings should not be made during frost unless deep snow is on the ground, as the young growth is then very brittle. The material must be taken out of the wood by means which cause a minimum of damage, and, if possible, before the next growing season commences. If, after the reniuval of the last shelter trees, bianl^s of ai)pi-ecialile extent exist, they must be ai-tilicially tilled up by THE STRIP SYSTEM. 237 planting strong plants on them, and in some cases perhaps 1)y sowings. <1. Mdilcinn the Trcrs for Eoinot'nl. What has heen said above shows clearly, that the success of natural regeneration by seed under a shelter-wood chiefly depends on a suitable composition of the latter during the several stages of the regeneration period, in other words, on a careful selection of the trees to be removed. Except in the case of experienced foresters, this must be carried out when the effect of the removal of a portion of the trees can be best judged, namely when the trees are in leaf. In the case of evergreen species the marking can be done at any time, but in woods containing deciduous species the marking should be done in summer or early autumn before the leaves fall. In carrying out the marking only a narrow strip should be taken in hand at a time, and the business should be supervised by a competent and responsible forester. 2. The Strip Sj/stent of Natural Kerieiwration under Sltelter-woods. As already mentioned, this system is a modification of the compartment system. Instead of conducting the regeneration process uniformly over a whole wood or compartment, the area is divided into a number of narrow strips, which are taken in hand, one by one, at such intervals, that generally three strips are under regeneration at one and the same time ; one being in the final stage, one in the seeding stage, and a third in the preparatory stage. As soon as one strip has been completely regenerated a fresh strip is taken in hand, and so on, until tlie process is gradually extended over the whole compartment or wood. In the appended Figs. 75 and 76, the strip marked /' is in the final stage, that marked s in the seeding stage, the one marked j^ in the preparatory stage, and the rest of the area marked ii is forest as yet untouched. The process of regeneration in each strip is the same as that described in the 238 NATT'RAL REGENERATION OF WOODS. ciiKe of the compartment system : there are the three stages, one folh)\vin«.' the ntlier. N.lUTH. Eam NoHTir. Wkst, Nothinf^ definite can l)e said re<^'ai-dinn; the breadth of the strips ; it depends on the species and tlie local conditions. THE GROT'P SYSTEM. 239 Those wlio advocate the system sa}- that, ordinarily, the breadth should not exceed the height of the trees. There is no limit to the length of the strips. The operation should generally commence on that side of the wood which is opposite to the prevailing wind direction : this rule may be overridden by other considerations, for instance an unfavourable distril)utibn of the age classes. In some cases the wood may, if necessary, be attacked in two or more places at the same time. For the rest, little or no difference exists between this and the compartment system, except that the area under regeneration is less concentrated in the former. 3. The Group System of Xatiiml Regeneration under SJielter-woods. If a forest is naturally regenerated under the compartment system it may happen that, after the seed cutting, the area is not, or only partially, stocked with a new crop. A second seed year must then be awaited, and in the meantime, the cover having been thinned, the soil may suffer considerably under the additional admission of light, so that it may not present a fit germinating bed when the second seed year arrives. Extensive working of the soil or artificial forma- tion has then to step in. With the view of reducing this drawback to a minimum, foresters hit upon the idea of taking in hand in the first place only certain limited groups, scattered over the compartment ; when these have been successfully regenerated, they proceed with a second set of groups, and so on, until the whole compartment has passed through the process of regeneration. In practice, the system has been further modified : certain groups, as before, are taken first in hand, and when these have been regenerated, they are gradually enlarged by regenerating successive narrow bands around them, and this process is continued until the several groups merge into each other (Figs. 77 and 78). The time required for the completion of the process in each wood, or iO NATntAI, HEGKXKHATION Ol' WOODS. compartment, is considerably lonj^Pi- tlian midei' tin- compart- ment system, and it extends generally over a period of 20 to 50 years, according to species and local conditions. A wood, while l)einp; regenerated under this system, presents a varying picture : some" parts of it have been completely 1, 1, 1. Points of attack (j^rmips of advance gniwtli;. 2. 2, 2. I ;j '.i 15 , ' ' ',' ',' - Successive eiilarffoinciits of groups. .'), 5, n. I regenerated, others are more or less advanced in the process, and others again are as yet untouched, with a complete cover overhead. When the whole process has been completed the young wood consists of trees varying in age by 20 to 50 years, according to circumstances ; it is in fact an uneven aged wood. THE GROUP SYSTEM. 24.1 a. Selection of Groups. The time when the different parts of the wood are attacked depends chiefly on the following considerations : — i. Advance Growth. In almost every mature wood groups of young growth are found, which have sprung up, here and there, before the Fig. 78. — Elevation of a section along a 6 of Fig. 77, in four successive stages. regeneration cuttings have been commenced ; such young growth is called "advance growth." Under the uniform s. H 24-^ NATlliAL KEGENEKATIUN OF WOODS. system it is not iiuich valued, partly because it f,'ives the youn<; crop an uneven character, and partly because, having stood for some time under the shade of the old crop, it is not always capable of developing into healthy full-sized trees ; hence, it is frequently removed altogether to make room for a uniform new crop. Under the group system all patches of advance growth, which are still healthy and capable of developing into full-sized trees, are carefully husbanded. They form the nuclei of the first regeneration groups ; the old trees standing over them are removed when no longer required, then the groups are enlarged, as indicated above, by gradually cutting away the immediately adjoining trees in narrow bands. ii. DlKFEUEXtKS OV Ann, CUOWIII. CnVKl:, AMI Sl'KCIKS. Many old woods are naturally of uneven age. In such cases the oldest parts are first taken in hand, followed by the next age gradation, and so on. Again, certain parts, for one reason or another, have not kept pace in development with the rest, nor are they likely to make up for it. They should be taken in hand first, so as to avoid loss of increment. Frequently certain parts have thiinied out naturally, followed by an hiterruption of the leaf canopy ; they must be attacked tirst of all. In mixed woods, groups of dilierent species may require regeneration at diti'erent times, ofifering an additional opportunity for a judicious selection of the groups first to be taken in hand. iii. I)ikiart of the State forests of Germany and France, where natural regenera- tion is adopted, though there is evidence that it will, in many cases, he superseded l)y the group system. The S3'stem partakes of the character of the compartment system carried out on small compartments ; the danger of failure over a large continuous area is avoided, and the shelter-wood is less liahle to be blown down, but tlje operations are less concentrated. '■. 7'/ir (//■('>'/) Sijslrtn. (1.) Tlie drawbacks are, that the operations are scattered over a largei- area at one and the same time, rendering super- vision more difficult and the transport of the material more expensive. (2.) The principal advantages of this system over the compartment system are : — (a.) It insures a more complete preservation of the factoi-s of the soil ; (//.) It affords greater security, especially in the case of shade bearing tender species, as regards the success of the regeneration, because it is carried out on small scattered areas at one time, so that failure in one does not imply failure in the others ; {<■.) Each group can be taken in hand when the most favourable moment for regeneration has arrived ; [(I.) The removal of the shelter-wood causes less damage to the young crop, as the material can be transported through the parts of the wood not yet regenerated. (8.) In summing up, it ma_y be said that the group system is in its place where the conditions of the locality or of the crop cliange from place to place, or where extremes of climate l)revail. It is admirably' adapted for the regeneration of mixed REGENERATION FROM ADJOINING WOODS. 247 woods, as it affords excellent opportunities for securing a proper mixture of the several species in the new crop. Above all, it is specially adapted for the introduction of a more regular system of working into selection forests. d. Tlir SclerHon Si/sfem. Here the drawbacks of the group system are further mten- sified, without offering sufficient compensation by way of advantages in other respects. True, the soil is still more completely protected, but this is generally accompanied by withholding from the young growth a suital)le measure of light. The system is, in Europe, confined to localities where the uninterrupted maintenance of a crop of forest trees is neces- sary for the protection of the soil against heavy rain, snow, wind, etc., in fact for so-called protection forests in high or steep mountains. It is also useful in forests of specially small or large extent ; in the former, if the area is insufficient for a regular division into compartments, and if nevertheless a certain quantity of timber is required annually ; in very large forests which are as yet in the first stage of systematic manage- ment, such as many of the forests of India. It is also prac- tised, generally in a rude form, where the demand for produce is as yet much below the supply. B. Natural Regeneration from Adjoining Woods. After the area has been clear cut, the seeding is effected by the seed falling from mother trees, which do not stand on the cleared area, but alongside of it. The points which demand attention are the conditions of success and the merits of the system. 1. C()H(Utio)is of Success, a. Sufficient Seedin(j of the Area. The agencies which carry the seed on to the area are air currents, and in some cases water, or the seed may roll by its 248 NATiHAi. kk(;knej{atiun ov woods. own weight down a slope. ^Vllen air cunents are the carrying' agency it is necessary that tlie seed should be sufficiently liglit, and that when it falls the wind should blow from the right direction. In this respect the species, the force of the air current, and the relative position of the regeneration area and the mother trees are of importance. The seed of some species, as poplar, is so light that it travels for miles, while that of others falls straight to the ground. Gayer gives the following distances for a number of species under the influence of a moderate air current. Birch, elm, larch, 4 — 8 times the height of the trees. Spruce, Scotch pine, alder .... 3 — 4 ,, ,, ,, Maple, ash, horn- beam .... 2 — 3 ,, ,, ,, Lime, silver fir . . 1 — 2 ,, ,, ,, Beech and oak, scarcely beyond the reach of the crowns. In the case of strong winds the distances are proportionately greater ; instances can be seen in Scotland where Scotch pine seed has been carried to many times the distances given above. The distances are also greater, if the mother trees stand at a higher elevation than the regeneration area. The direction of the wind during the fall of the seed intro- duces a great element of uncertainty, as it can only in rare cases be relied on. A further complication may arise if the seed sliould fall during the prevalence of a dry east wind, while, for other reasons, regeneration should commence in the east and gradually proceed towards the west. Ik Siiihihle Coiiililinn of the (Hfrminaliini llrd. This has often to be provided by working, or woimdiiig the soil. Where the roots of the trees are grubbed out the soil is sutiHciently stirred, but where the stools remain in the grou)ul wo)kiiig may be necessary. REGENERATION FROM ADJOINING WOODS. 249 c. SecurHij (ujainst crfernal Ddnijcis. These are chieflj^ frost, drought, and a growth of weeds. Some protection will be given by the adjoining wood, but the amount depends on the breadth of the area under regeneration at one time, and the relative position of the mother trees. (1. Extent of the (J tear inn . The smaller the regeneration area is, the more satisfactory will be the results. On large areas a period of 10. 20, or more years may be required to complete the new crop, which will be very uneven, and in the majority of cases artificial sowing and planting has to step in. The chances of success are much greater if the regeneration area has the shape of a narrow strip running along the edge of the mother trees. The breadth of such strips should not exceed the height of the mother trees, so that the area may l^e quickly and fully stocked, and better protection provided for the young crop against climatic dangers ; the soil keeps also fresher. Such protection is further increased if successive clearings do not adjoin each other, but are separated by older woods. Sometimes the clearings represent patches situated in the middle of old woods. Arrangements of this kind lead, how- ever, to a verj' complicated system of management ; lienee they occur only where groups of trees have been thrown by wind or snow, or killed by insects. If patches are cut purposely, they often lead to the group system described above. 2. Merits of the System. Owing to the uncertainty of the seeding and the injuries to which young tender plants are exposed, the system can be recommended only under favourable conditions of the locality and in case of hardy, quick growing species. Damage by insects, especially the cockchafer, Hylesinus, and Hyhirgus, further narrows the limits of applicability. :2o(l NATl'HAL HKGENHHATION OF WOODS. SkcTION 11. NaTLHAL PiEGKNKItATloN 1!V SllnoTS AND SUCKKRS. It lias been explained in Part I.,* that woody plants can reproduce themselves b}' means of shoots, or suckers, or botli. Shoots may sprinp; from the stool, after the tree has been cut over close to the ground, or from the stem and top. if the cutting is restricted to the side branches and the upper part of the stem. Accordingly a distinction may be made between regeneration from the root, stool, or stem. Of these, repro- duction by stool shoots is b}' far the most important, but as in many cases it occurs in conjunction with reproduction by suckers, the two will be dealt with together. 1. Refimeratio)! In/ Sfool SJinotn and Siicl.rys. As already stated, regeneration follows the cutting over of the trees. Where stool shoots are wanted, the cutting over takes place close to the ground, followed by a clump of shoots which spring either from adventitious buds formed on the callus near the edge of the cut, or from dormant buds on the neck of the stool. A similar mode of cutting is employed where both stool shoots and suckers are wanted. If only the latter are desired, the stump may be removed, and only the roots left. The success of this system of I'egeneration depends on many things, of which the following require special attention. Of the species growing in temperate Europe only broad leaved trees and slirubs are adapted to the method, and even amongst these great differences exist in regenerative power. t 0. Af/et'f Wooil nl 7'i/nr (>J[ ( 'i/lli/i;/. Generally, reproduction is most powerful during youth up to the period of principal height gi-owth,and under favouralde • Spc paeo fi". i Soo pajzf <>", REGENERATION BY SHOOTS AND SUCKERS. 251 ircumstances for some time beyond it. Hence the wood must be cut over for ihe first time at a period not lieyond the end of the principal height growth. After that, the rotation depends on the required description of material (firewood, hop poles, bark of a certain quality, etc.), and the time up to which the stools are capable of vigorous reproduction. The increment of coppice woods is also greatest during the first few' 5'ears after cutting, which may be another reason for the adoption of short rotations. On the other hand, small material has of late years so much sunk in price, that the w^oods are frequently allowed to grow until they are capable of yielding small timber. c. SoiinilDOKs nf Sfodh. Diseased stools often produce diseased shoots, though some species, as oak and hornbeam, are usually exempt from this liability ; tlie same holds good in the case of suckers. It follows that diseased stools should be removed and replaced by strong plants to produce fresh and sound stools. The longevity of the stools is closely connected with their health, which is principally governed by the species and the character of the locality. A fertile soil and favoural)le climate increase the longevity. The stools of ash, maple, birch, and also those of beech, are short-lived, lasting frequently not longer than two or three rotations ; those of oak and horn- beam are almost indestructible, and between these extremes many intermediate stages exist. d. Man tier of Vtdfiinj. The cut produced by the removal of the stem is exposed to the effects of air, moisture and sun, which cause a deteriora- tion of the wood near the cut through drying up and rot, and tend to reduce the reproductive power of the stool. Although this process of deterioration cannot altogether be prevented, its extent and rapidity can be reduced by careful cutting. In the first place the size of the cut should not be 252 NATTRAI, HKGKNKHATION OF WOODS. ton liiif^e, ill the second place it should he smooth, and linally it slionld he slanting, so that water may not rest on it (Fig. 79). In the case of large slioots, the cut may he given a slope from the centre to two sides, or it may receive the sliape of a cone (Fig. 80). The cut should on no account slope inwards (Fig, 81) ; it should be made with a sharp billhook or axe, and not with a saw. If the latter is unavoidable, the cut should be given a smooth surface with a billhook, axe, or knife. Another important point is that the bark should not be severed from the wood around the edge of the cut. The height from the ground at which the tree is cut over also influences the success. Except where inundations are feared, it is preferable to cut close to the ground, and there is less corky bark on the root neclc : besides, if the shoots appear ^^^^^■'ii^w.v- Good. 11,,./. Fi,f. Fig. -i). low down, at or a little below the surface, they are more likely to develop independent roots, and thus ensure greater longevity of the stool. In southern countries, where the sun may diy up llie stools. it may be necessary to cut below the ground, or to cover up the stools with earth. c. Season ,if CiiUiiiij. The best seasmi of the year for cutting is a few weeks before tlu! buds be^^iii to swell. Various circumstances may, how- ever, prevent this being done, such as an insuihciency of labour, the necessity for peeling the wood, etc. ^Vhere labour is not available to do the whole cutting at the most favourable period, a part must be done (in Europe) hi the autumn ; tliis has the drawback that frost during winter frequently separates REGENERATION BY SHOOTS AND SUCKERS. 353 the bark from the wood of the stool, or that the stools are killed outright. Again, stools which were cut over in autumn send out shoots somewhat earlier in spring, and thus render them more lial)le to be injured by late frosts. Where the principal object is to obtain bark for tanning, the cutting must be done during the full flow of the sap, that is to say, in temperate Europe, in May and the beginning of June. /. Standanh. The reproduction is most complete if the wood is clear cut ; the more standards are left, the less favourable will be the crop of shoots and suckers. 2. Rcproduct'uDi hy Stem Slioot!^, or PoJJardiiui. Pollarding consists in the removal of the crown of a tree, either leaving the main stem intact or cutting it off at a certain height from the ground ; in tlie latter case the system is frequently called topping. The branches may be cut off close to the main stem, or at a short distance from it, the latter method being preferable. New shoots spring from the cuts, and these are again cut after one, two, or more years, according to the desired size of the produce. What has been said above regarding species, health of the mother trees, and manner and season of cutting, holds mostly good also as regards pollarding. The system is chiefly employed in the case of willows and poplars ; the former yield materials for basket work, fascines, hurdles, etc., and the latter firewood and small sticks for domestic use. ^.04 CHAPTEli l\. FORMATION OF MIXED WOODS. The various methods of foniiin;^ }i wood described in tlie previous chapters of tliis part are appHeable to both pure and mixed woods. There are, however, certain peculiarities in the formalii)ii of mixed woods, which it will be necessary to indicate. As the number of possible mixtures is very larj^e, a separate reference to each is impossible. It must sufltice to deal with them in the following groups : — 1. Formation of even aged woods, or in which the ages of the species in mixture differ so little that they may. for practical purposes, be considered as even aged. 2. Formation of mixed woods consisting of trees of uneven age, such as high forest with standards, two-storied high forest, etc. 1. r'oniiatio)! ()f Ernt At/rd Mi.vcil Woods. In Fart I. of this volume (i)age 74). it has been explained that in order to preserve mixtures in which the species are of the same age, the latter should show nearly the same rate of height growth throughout life. Whenever this is not the case, any species sensitive to cover and likely to be outgrown by associated species must be given a start, while the latter must be capable of bearing the shade of the former. In the absence of these conditions the species must be separated, and the utmost which can be done is to place them in alternating groups. Even then there is no certainty that in regenerating such a wood the new crop will show the desired mixture. At any rate it will be clear that the regeneration of such woods requires constant attention, lest one species should oust another. EVEN AGED MIXED WOODS. 1^55 a. Sowiiu/ and PlanUnfi in Clear Gutting^. Sowing can be done by mixing the seed of two or more species, or by sowing one over the other, either direct or crosswise. The second method must be followed whenever the seeds require a different covering, that which requires the deeper one being sown first. Another method is to sow in alternate strips. Sach sowings are rarely made nowadays, but recourse is had to planting, as it permits the .mixture being arranged in any way which may be desired. The species may alternate by single plants, or by lines, or strip- or group-wise. Again the proportion of one species to another can be absolutely fixed. Planting in groups is specially indicated where the conditions of the soil change from place to place, as each patch can receive the most suit- able species. The size of such groups depends on circum- stances ; if it exceeds a certain limit, the wood can no longer be considered mixed — it becomes a series of pure woods. Where a light demanding species is to be mixed with a shade bearer, the former can be given a start of a few years, instead of arranging the mixture by groups. In such cases the mixture is frequently arranged by lines, the light demand- ing (and generally hardy) species being planted first in alternate lines, and the shade bearing species (generally tender in early youth) afterwards in the intermediate lines. Another way of giving one species a start over another is to put in plants of different ages. In some cases one species is raised with field crops, while the other is planted in, when the cultivation of the field crops has ceased. Formerly it sometimes happened that one species was raised by sowing and the other by planting, but this is rarely done nowadays. h. So/ring and Planling under SlifUvr-woinh. This method is followed in the case of species which are tender during youtli, especiall}' in respect of frost. 256 FORMATION OF MIXKl) WOODS. If an old wood exists, and a new mixed wood, consisting of a tender and a hardy species, is to be created, tlie former may be sown or planted alone under the shelter-wood ; llien, when the shelter-wood is no longer required, it is removed, and the second, hardy species planted in. This method is followed, for instance, where beech is to be mixed with Scotch pine or larch. If no old shelter-wood is available, then the hardy species is cultivated first, and when it has advanced sufficiently to provide the necessary shelter, the tender species is intro- duced. In this way Scotch pine, larch and birch are planted to serve as shelter- woods (nurses) for beech, silver fir, and oak. c. Xdiural Rcucncrdiiiin wider S/ielfer-troot/s. In regenerating a mixed wood it is of first importance that the shelter-wood should be composed of trees of the several species in such proportion as to secure the desired mixture in the new crop. In determining that proportion the relative reproductive power of the species must be taken into con- sideration, more especially the size and quantity of the seeds, the frequency of seed years, the height growth of the species in early youth, and its capacity of bearing cover ; its degree of hardiness, the nature of the germinating bed, vIvc, Already during the last thinnings the cuttings can be so arranged as to lead to a proper proportion of the mother trees. This process is continued, and if possible completed, during the preparatory stage. Under any circumstances it must be completed by the seeding cutting. In many cases a great difficulty arises from the fact that the several species do not seed in the same year. In such cases the seeding cutting must be made, when that species seeds which is to form the Inilk of the new crop, or which is the more difficult to rear ; the other species, if they have not produced a sufficient proportion of seedlings beforehand, or fail to do so within a few years afterwards, must receive artificial assistance. EVEN AGED WOODS. 257 The arrangement of the cuttings during the final stage depends on the requirements of the new crop in the several parts of the wood. Where conflicting interests present themselves, those of greater importance must prevail. The trees to be left for the final cutting should belong to the most wind firm species, to that which is most likely to increase rapidly in size and value, and if possible to one with a thin crown. The above remarks show that it is in many cases a difficult task to guide successfully the process of refieneration in a mixed w'ood ; hence a method should be chosen which reduces the difficulties to a minimum. With this end in view the several species may be brought together in groups, each of which can be treated in the manner best adapted to the par- ticular species. If this should be found insufficient, the following method must be adopted : — (I. Natural Rfgeiwralidii coinhiiied u Ith Sowiiiy and Plantiaij. Natural regeneration alone rarely leads to the desired result ; only parts are successfully stocked, and sowing and planting must step in to complete the business. In applying this method it must be remembered that generally the more favourable parts of the area become naturally stocked, leaving the inferior spots blank. If only the latter were filled up by sowing or planting the species which is deficient in the naturally regenerated patches, it would be relegated to the bad spots, while the other species would occupy the better parts ; hence it is necessary to plant a proper number of the artificially reproduced species also within the patches already naturally regenerated. This method is much used in Europe in the formation of mixed woods of beech with oak, ash, sycamore, and other valuable timber trees. In fact it is the best method for such mixtures. The valuable species are generally introduced by putting in strong plants ; sowings are also done in the case of .• s 258 FORMATION OF MIXED WOODS. shade bearing species, or where the species are arranged in separate groups. Another instance is the regeneration of silver 11 r and spruce woods in the Black Forest. There silver lir is favoured during the regeneration process, and if an insufficient number of spruce plants has sprung up, it is afterwards increased by planting. 2. Formation of Mixed Woods oj Uneven Age. It has been shown that the preservation of the mixture is difficult, when the trees ai-e of the same age, or nearl}- so, and that it requires constant care and attention, lest one species should be suppressed b}^ another and disappear. Such unre- mitting attention cannot always be given, apart from the expense which it involves. Endeavours have been made, therefore, to devise a method of mixing species which is less dependent on constant attention, and this has been found in giving to the mixed species a greater difference of age. Such an arrangement causes a considerable difference in the ages of the component parts of the wood. Each of these requires to be regenerated at its own time, so that the process of regenera- tion is gone through several times in the course of one rotation, one part of the wood being regenerated on each occasion. Many varieties of mixed woods of uneven age have been evolved, each of which corresponds, more or less, with a distinct sylvicultural system. Of these the following claim attention : — (a.) The group and selection systems. {h.) High forest with standards. (o.) Two-storied high forest. {d.) Mixed coppice with standards. a. The Grovp and Seler/ion ,^f/s/ems. Under the group system the regeneration of a wood extends over a period ranging up to 40 and even 50 years. By first regenerating the groups consisting of the threatened species, UNEVEN AGED WOODS. 259 they can be given a start up to 30 or 40 years. After these have been regenerated, tlie groups consisting of the threatening species are taken in hand. Taking, for instance, a mixture of light demanding and shade bearing species, such as oak, larch, or Scotch pine, ^Yith beech, silver fir or spruce, operations commence with the groups of the former, and are brought to a close by a regeneration of the latter. Again, in a mixture of shade bearers only, such as beech, silver fir and spruce, the last mentioned is likely to outgrow the beech and also the silver fir ; hence a sufficient n amber of groups of beech and silver fir are first established, and then the groups of the spruce. In the case of selection forests the differences in age are still greater, and much can be done on the lines indicated above, to protect the threatened against the threatening species. b. Nif/h Forest irith Standards. If such woods are mixed, the threatened species are selected for standards, if otherwise suitable for the purpose ; it is essential that the rotation should not be very high, otherwise the future standards may suffer l)efore the end of the rotation has been reached. c. Two-storied High Forest. It has been explained in Part I., page 103, that when a high forest has run through part of the fixed rotation, a portion of the trees are removed, and a new crop is introduced, which grows up between the trees remaining of the first crop, the two being allowed to run through an additional whole rotation. The difference between the two crops ranges, as a rule, from 20 to 60 years. Here then is an excellent opportunity of pro- tecting a threatened against a threatening species, the first crop consisting of the former, and the second of the latter. In Europe the system is much adopted for the production of large- sized oak, larch and Scotch pine, also ash, maple and others, which at a certain age are underplanted with beech, s2 200 FORMATION OF MIXED WOODS. silver fir, spruce, hornbeam, sweet chestnut and hazel. This underpUinting had best be done in the case of larch at the age of 10 to 20 years, of Scotch pine at 20 to 40 years, and of oak at 30 to 50 3'ears or even later. (I. Mixed Coppiro ivilli SfnniJnnls. This system offers, in the regeneration of the over wood, the greatest latitude for the protection of threatened species, whether in single trees or in groups. Although some of the standards may regenerate themselves naturally, the gieater part are produced by planting strong plants where mature standards have been removed. •261 CHAPTER Y. CHOICE OF METHOD OF FORMATION. The choice of method depends on numerous considerations, such as the sylvicultural system, species, soil, climate, external dangers, labour, cost, etc. To attempt a detailed exposition of these matters in reference to the several methods would not lead to any practical result, since, after all, the choice depends on the local circumstances of each case. A few remarks regarding the main groups of methods may, however, not be out of place. These main groups are : — (1.) Direct sowing. (2.) Planting. (3.) Natural regeneration by seed. (4.) Natural regeneration by shoots and suckers. Of these the last-mentioned method refers almost entirely to coppice woods worked under a short rotation ; it is not employed where woods are treated under a high rotation, because in very rare instances only do coppice shoots reach the same size as seedling trees. The questions which interest the sylviculturist most are — (1.) "Whether to sow direct, or plant on cleared areas. (2.) Whether to regenerate existing woods artificially, or naturally by seed. (3.) Whether or not combinations best meet the objects of management. These three questions, then, will be shortly discussed in the following pages. 262 C'HOKK OF MHTHOI* oK FOIOIATION. Section 1. — Ciioict: ]iET\VKi:N \)in\:ci Sowinc; and I'lanting. Formerly the artificial formation of woods was chietiy eflfected by direct sowing, planting being restricted to special cases where the other method was not likely to succeed. The reasons for this were, that sowing was considered to be more certain and cheaper, since it was generally the custom to use too large transplants. In the course of time the raising of plants was elaborated, smaller plants were used and the expense considerably reduced, so that now far more planting than direct sowing is done. Yet it is not always a foregone conclusion that planting is better or more suitable than direct sowing, since many differing conditions and factors affect the ultimate results. The effect of some of these factors is as yet somewhat obscure, but in many respects experience has taught the forester, which of the two methods is preferable under a given set of conditions. The points of view from which the choice of method may be approached are manifold, and amongst these the following deserve attention : — (1.) Objects of management. (2.) Desired sylvicultural system. (3.) Selected species. (4.) Conditions of locality. (5.) External dangers threatening the young wood. (6.) Quality and quantity of available labour. (7.) Cost. 1. Olijiuts of MdiKKifiiiriit. The objects of management are shortly indicated on pages 1 and 2, and it will readily be understood that, according to circumstances, either planting or direct sowing may more completely meet them. Where landscape beauty is the object aimed at, few foresters would think of adopting direct sowing; where time is an object and expense of minor importance, the planting of strong transplants would be most siiitalilc. If the ol)j('ft of DIRECT SOWING VERSUS PLANTING. 263 management centres in the production of the greatest possible quantity of small material, with the least possible outlay, direct sowing would probably yield better results than plant- ing. Again, for the production of clean timber trees sowings, with their greater density, in many cases may be more suit- able than planting, unless the latter be very close and thus involve a considerable outlay. Economy in working is one of the leading requirements in sylviculture. In this respect either sowing or planting may be preferable, according to circumstances ; experience, how- ever, shows that where plants of good quality can be raised at a reasonable outlay, planting yields higher and more valuable returns than direct sowing, if time be taken into consideration. Where the land is required for pasture or grass-cutting, planting is decidedly preferable, as cattle can be admitted at an earlier age, while grass-cutting can be commenced at once. 2. Si/lvicultural System. The formation of woods to be treated under the pollarding system, and of osier beds, is best effected by planting. The same may be said of ordinary coppice woods and the produc- tion of standards in coppice. In ordinary seedling forests, either method may be adopted. 3. Species. The species affects the choice of method in various ways. In the first place many species produce seed abundantly only at irregular and often long intervals ; hence continuous opera- tions can be carried on only by planting, as the production of nursery plants requires comparatively small quantities of seed, and this, if necessary, can be obtained from a distance. By keeping a quantity of reserve plants in the nursery, seedless years may be tided over without interrupting the work. Species, the seed of which germinates with difficulty or slowly, or the seedlings of which are tender in early youth. 2d4- CHOICK OF MKTHOI) OF FORMATION. should be propagated in llic case of clear cuttings by planting and not bj' direct sowing. In such cases it is much easier and cheaper to provide the necessary tending and protection in a compact nursery than on an extensive forest block. Under shelter-woods direct sowing may be preferable. Hardy species, which grow slowly during youth, should be planted ; those of fast and early development may be sown direct, if this be desirable on other grounds. The shape of the root system is also of importance. Species which develop a compact and comparatively shallow root system are much easier to plant than those which at once develop a deep going tap root ; for the latter, direct sowing may be advis- able. Long tap roots, however, may be pruned, or the seedlings raised in such a manner that they are forced to develop a compact root system ; at the same time either alternative may be of doubtful expediency. Mixed woods should be established by planting, as a proper mixture of the species is rarely practicable by direct sowing ; at any rate some of the species must be planted. Frequently it is desirable to give one species a start over another, and this can be done in a satisfactory manner liy tlie use of large plants. In the case of some species, as for instance oak, many foresters maintain that direct sowing gives more vigorous and better trees, but this depends to a large extent on the soil and climate, and also on the size of plants used. If sowing of acorns is not advisable for other reasons, the planting of one or two years old oak seedlings close together is likely to yield just as good oak trees as direct sowing. 4. Conditions of Locality. As a general rule it may be said, that planting is preferable whenever the conditions of the locality are unfavourable, especially where extremes of soil and climate prevail, while in a favourable locality direct sowing may yield eijually good, and in the ease of some species even better, results. DIRECT SOWING VERSUS PLANTING. 265 Unfavourable localities are those with a wet, occasionally inundated, or very moist, heavy, cold soil ; excessively loose, dry, or poor soils ; those subject to be overrun by a heavy growth of weeds, or where frost lifting may be expected. Similarly, planting is far preferable to direct sowing where extremes of climate prevail, such as in raw, frosty, exposed localities. On steep slopes planting is also preferable, but in very stony soil direct sowing may become a necessity. 5. External Dangers. Seeds, as well as young seedlings, are subject to attacks by various animals, against which they can be more eli'ectually protected in a nursery than in the forest ; hence, on this account, planting is preferable to direct sowing. As regards attacks by insects, it is an open question which of the t^vo methods is preferable. As long as only thoroughly healthy plants are used and put out with care, they may hold their own and even do better than seedlings in direct sowings ; but weak plants, or those which have difficulty in establishing themselves quickly in their new home, are more subject to attacks by insects than seedlings grown in situ. The same often holds good as regards attacks by fungi. 6. Labour. Unless direct sowings necessitate a thorough working of the soil, they require less labour than planting. Where labour is scarce direct sowing, therefore, may prove to be cheaper. Planting also requires more skilled labour than direct sowing. 7. Cost. Whether direct sowing or planting is the cheaper method depends on the price of seed, the extent to which the soil has to be worked for direct sowings, and the cost of plants. Direct sowing is generally cheaper, but if seed is expensive and 266 tHOK'K OF METHOD OF FORMATION. small plants can be utilised, plantin«^' may be the less costly method of the two. Section II. — Choice jjetwken Artificial Regenef.ation and Natural PiECiENERATioN ry Seed. Sowin<^ and planting can be done under the shelter of the old wood, or it can follow a clear cutting ; natural regenera- tion can be done under a shelter-wood, or on cleared areas of moderate breadth by seed coming from an adjoining wood. The differences between the two shelter- wood methods are small, while they are considerable between the clear cutting and shelter-wood methods. The following remarks refer chiefly to the latter case. 1. Merits of Artijicial lictinirratio)!. (I. AiU'ditlaijos. (1.) Artificial regeneration is independent of the local occurrence of seed years, since sufficient seed for nurseries, and frequently also for direct sowing, can always be obtained from a distance. This being so, the adoption of the method enables the forester to proceed in a systematic and regular manner, doing the desired quantity of regeneration year after year, and providing the market with a steady supply of produce. (2.) The full enjoyment of light can be secured at once to young trees which are hardy. (3.) The trees develop more rapidly than those originating 1)y natural regeneration, at any rate up to middle age. }i. iJisddran laiips. i\.) Sowing and planting are costly. The outlay on the latter can, however, be considerably reduced l)y planting small plants according to a simple and cheap melliod. (2.) "Where artificial regeneration follows clear cutting, tlic young plants are e.xposed to damage l)y frost, drought, insects ARTIFICIAL VEHSUS NATURAL llEGENEKATION BY SEED. 2t)7 and weeds in a far higher degree, than if the regeneration is conducted under a shelter-wood. In fact, tender species must be raised in the latter way, so that for them clear cutting is excluded. Insects frequently become formidable to coniferous woods raised in clear cuttings, while experience has shown them to be less dangerous to natural seedlings, especially when these are raised under a shelter-wood. (3.) In the case of clear cuttings, the laying bare of the ground for a series of years may seriously affect the fertility of the soil, so much so that the method is hardly admissible on inferior soils. 2. Merits of Xatiiral Rrf/eiieration hi/ Seed. ((. Adraiif/ff/ffi. (1.) Natural regeneration involves less expenditure than sowing or planting. In some cases the outlay may be abso- lutely nil, but in most cases some artificial help has to be given either by working (wounding) the soil, or by sowing and planting. Still the outlay is considerably smaller. It must not be overlooked, however, that in the majority of cases natural regeneration requires much time ; as long as the shelter trees increase sufficiently in size and quality so as to make up for any loss on this account, no harm is done, but where this is not the case, artificial regeneration may be actually more profitable, since no loss of increment occurs. (2.) Damage by frost, drought, and weed growth is avoided, or at any rate considerably reduced. The same may be said as regards damage by insects, though perhaps not to an equal extent. (3.) The activity of the soil is maintained, and, to a considerable extent, rendered independent of climatic influences. (4.) Owing to the greater number of plants per unit of area, clearer and straighter stems are produced than in plantings, and also frequently in sowings, though the difference in the 268 CHOICE OF METHOD OF FORMATION'. latter case is lef4s decided. This adv;iiita,i;c can be nuUitied to a considerable extent by dense planting and sowing, l)ut in that case the cost is proportionately increased. //. I>isinlr(iiil(i)ics. (1.) The method is more complicated and ditttcult than artificial regeneration ; hence it demands more skilful foresters. (2.) The intermittent nature of seed years produces many drawbacks as regards the equalisation of the yield and the control of operations. (8.) The removal of produce is also more expensive. 3. SunnitiiKj iij). Neither the arlilicial nor the iiutural method of regeneration is the best at all times and under all circumstances; only a consideration of the. local conditions can lead to a sound decision as to which is preferable in a given case. In forming such a decision the forester must take chiefly the following points into consideration :— (a.) General objects of management. {}>.) Species to l)e grown. {(■.) Condition of locality. {(l.) Available funds. {e.) Skill and capacity of the stall". Section III. — Combination of Several Methods of Formation. In the preceding pages various artificial and natural methods of forming a wood have been described. Kach of these metliods has special advantages under certain condi- tions. As the latter may, and frequently do, vary within a narrow extent of area, it follows that two or even more methods may be employed in the fornuition of a wood, thus secui'ing greater success and fre(|uently a I'cdiictioii of cxpeiiditin'e. COMBINATIONS OF SEVERAL METHODS. 269 In fact, in practical sj'lviculture such combinations are tlie rule and not the exception. Of the combinations here indicated the following are of special interest : — 1. Combination of Artificial Formation and Natural liefieneration by Seed. Natural regeneration assists artificial formation only in rare cases, but the reverse constantly happens. Natural regenera- tions by seed rarely are so complete that they do not require artificial help, which can be afforded by sowing or planting, generally the latter. There are always certain parts of the regeneration area which, for one reason or another, do not become stocked and have to be planted up. Then it frequently happens that the ruling species shall be mixed with others which must be brought in artificially ; or one of the species in a mixed wood fails to produce seed for a considerable period, while the other, having regenerated itself, demands the removal of the mother trees. In many cases it can l)e foreseen that certain portions of an area are unfit for natural regeneration ; these may be artificially stocked at once, even before the natural regeneration of the remainder has commenced. In other cases a part of the area may have been deprived of the necessary shelter trees by natural phenomena ; here artificial shelter- woods may have to be planted. From the above remarks it will be seen that artificial and natural formation may be started at the same time, or the one may precede the other. In all such cases, blanks in existing w^oods should be filled up with strong plants of a quick growing species. 2. Combination of Artificial Formation with Regeneration by Stool Shoots or Suckers. This combination occurs constantly in coppice woods, where stools, which have died or become diseased, are replaced 270 CHOICE OF METHOD OF FORMATION. artificially In- putting,' in stn)iiy sowing seed, such as acorns or chestnuts. Only in rare cases are such stools replaced by natural seedlings. 3. Combination of Xntiirdl Ilef/encration by Seed witli Rcfjeneration by Stool Shoots and Suckers. This case may occur in high forest, where the seedling trees have been injured by frost, game, cattle, mice, hail, etc. ; it may then be advisable to cut them back in order to get strong healthy shoots. The combination occurs further in coppice with standards. Here it is desirable that the standards should be seedling trees, and their regeneration may be effected by the seed falling naturally on the ground. 4. Combination of Artificial Formation witJi Xatnral Ilef/eneration by Seed and by Slioots. It occurs in coppice with standards, when a sutttcient number of the latter cannot be obtained by natural regeneration. 271 PART III. TENDING OF WOODS. 27:3 TENDING OF WOODS When a wood has been established it will, if left undis- turbed by outside influences, grow on and reach maturity ; the individual trees will, however, enter upon a lively struggle for existence, and the ultimate results, in the majority of cases, will meet only to a limited extent the objects for which the wood has been established. Moreover, external injurious effects will make themselves felt, and further reduce the returns. In order to realise those objects more fully, especi- ally where a certain class of timber is desired, the growing wood requires well-directed tending from its formation up to the time when it is finally cut over. Care must be taken that the most favourable conditions for growth are secured, and that the development of the individual trees is so guided as to produce the desired results ; in other words, the forester must take measures to preserve the continued activity of the locality, and to see that the wood has throughout its life a suitable composition. The subject divides itself natural into the following two sections : — (1.) Preservation of the factors of the soil. (2.) Tending the crop of growing wood. It is not, however, intended to enter here in detail upon all the matters which contribute to, or interfere with, the desired result. The effects of the locality upon forest vegetation, and vice versa, have been dealt with in Part I. of this volume, while the protection of the soil and growing wood against injurious influences will be dealt with in a subsequent volume on Forest Protection. In this place only the important points will be shortly indicated, with special reference to the sylvi- cultural aspect of the subject. In order that a crop may be fully productive, it is necessary 274 TENi)iN<; OF Woods. to establish and then to preserve those physical and chemical conditions of the soil on which a health}' and vigorous growth depends. The means adopted in agriculture for this i)ur[)ose are working the soil and manuring. Both are expensive, and in sylviculture they are only feasible in cases where the increased returns at least cover the outlay ; they are therefore either out of tlie question, or can be employed only to a very limited extent, and the forester must endeavour to accomplish what is needful by other means. Fortunately timber trees are far less exacting than field crops, so that the more modest means at the disposal of the forester suflfice for their healthy development. It has been shown on page 34 that the productive power of the soil in sylviculture depends on : — (1.) A sufficient depth ; (2.) A suital)Ie degree of porosity ; (3.) ,, J, ;i moisture ; (4.) ,, chemical composition. For sylvicultural purposes these conditions can be procured to a sufficient extent by the following simple agencies : — (a.) The preservation of a suitable cover overhead ; {b.) The preservation of the natural covering of the soil, more especially' of humus. How these affect the soil has been described on page 41. The principal fact is, that the activity of tlie soil and a vigorous development of the crop growing on it are intimately con- nected with each other, and that one exercises a healthful effect upon the other. At the same time the requirements of tlie one may be opposed to those of the other, and it must be a leading principle that the tending of the crop should always take into consideration ii ])i(ip(u- preservation of the fertility of the soil. The above remarks lefer to the case of woods wliich are fully stocked, in other words, crowded woods. Cases may INTRODUCTORY. 275 occur, however, where it is desh-able to interrupt the leaf canopy at a certain age so as to form open woods ; in such cases separate steps must be taken to preserve the fertihty of the soil. Again, during the lirst part of the life of a wood it is subject to special dangers, most of which disappear later on, when the attention of the forester must be directed to other matters. The subject may, therefore, be divided into the following three chapters : — Chapter I. — Tending of Woods during Early Yolth. ,, II. — Tending of Crowded Woods after Early Youth. ,, III. — Tending of Open Woods for the Produc- tion OF Large Timber. T I 276 CHAPTER I. TENDING OF WOODS DURING EARLY YOUTH. Young woods require special protection against external dangers until they can shift for themselves ; they must l)e kept clean, and a proper density or composition of the crop preserved. iVccordingly the subject will be divided into four parts. 1. Protection tujaiiDit Kxtenial Ifaiuicrs. The details of this subject will be found under Forest Protection. For the present pur])oso the following notes will suffice. a. Fire. Although woods require protection against lire at all i)eriods of their life, it is specially necessary during early youth. Protection is atiorded by removing all intiammable matter, or clearing lire traces around the area and at suitable intervals in the interior. In addition, the area must be watched, so that any tires which occur may be promptly extinguished. l>. Fras/ (ind Ih-aiijlhl. \\here regeneration takes place, whether naturally or artificially, under a shelter-wood, the latter provides the necessary protection against frost and drought, or, at any rate, insures a considerable reduction of the danger in either case. In cultivating cleared areas, shelter for tender species must be artificially provided by growing simultaneously, or beforehand, a special shelter-wood, or nurses. The trees selected for this purpose must be frost-hardy and possess a thin, or moderately dense crown. The best nurses in tem- perate Europe are birch. Scotch pine, and larch. Where EXTERNAL DANGERS. 277 danger fi-oiii late frost is excessive, larcli, owing to its early sprouting, is less well adapted as a nurse, l)ut it does very well in all other localities. In moist localities alder and willows have been similarly used. The nurses may be distributed evenly over the area, or placed in alternate lines. They are removed when the tender species can do without them. Frequently some of the nurses are retained so as to form a mixed wood. r. Cold Winds. The effects of raw, cold winds are often more disastrous than frost produced locally by radiation. Where they are to be feared, lateral as well as vertical shelter is required. This may be given either by adjoining woods of sufticient height and density, or, in their absence, by artificial shelter belts, or wind breaks. These must be dense, and they should be established some time before the area to be protected is placed under cultivation or regeneration. The species of which wind breaks consist should if possible be evergreen, and with dense crowns coming close to the ground, such as spruce. All alternative measure consists in mixing a hardy species, such as Scotch pine, with a tender crop. Or the wood is treated under the selection system, when trees of all ages are intermixed on the same area. In that case, the middle aged and younger trees provide lateral shelter for the young growth, while the old trees give vertical shelter. In all these cases it is essential that the edges of the wood, towards the side whence cold winds blow, should always be kept as dense as possible. What has been said above applies not only to frost, but also to drought, more especially in tropical climates, \yhere hot, dry winds may be even more disastrous than cold winds are in higher latitudes. d. Weeds. In the case of the shelter- wood systems, under regular and successful management, noxious weeds and objectionable ilS TEN1>IN(; OF WOODS DTRING EAHI.Y YOT'TH. species of trees are kept .sufiiciently in check to enalde tlie young tree growth to make its way up through them. If tliis is not the case, and in the cultivation of cleared areas, noxious weeds must be removed wherever they threaten to choke the young plants, until the latter have reached a sufficient height to hold their own. Heather, broom, brambles, climbing plants, l)irch, sallow, etc., may become even more dangerous than ordinar}' grasses and weeds. In considering the degree to wliich noxious plants require to be cleared awaj', it must be remembered that in moderation they may act beneficially, by sheltering the very young trees ; hence interference is not called foi- until they actually become noxious. r. /iisrr/s (I ml FiiDiji. These form standing dangers to woods througliout life, especially where coniferous trees are growMi over extensive areas. The measures whicli should be adopted to protect forests against them are taught in Forest Protection. Several species of both insects and fungi are specially dangerous to young forest plants. It is the duty of the forester to watch carefully his regeneration areas, and to destroy all injurious insects as soon as they appear, so as to prevent the spreading of the evil. In many cases it is necessary to let areas lie fallow for a few years, until insects, which breed in the stools and the refuse of the old wood, have disappeared again. As an illustration JIiflohiKs ahirth. the pine weevil, may be mentioned, which frequently becomes disastrous to young Scotch jiine and spruce woods. In the case of attacks by fungi, the diseased plants should lie removed and destroyed as speedily as possible. 2. Prcsrrratioii of y lemoving the lower branches the vigoui- in tlie upper part may l>e restored. This case applies specially to oak standards, the boles of which, exposed to light after a prolonged crowded position, have developed epicormic l)ranclies. 2. Daiiticra cimncricd icitli Pnnniui. The removal of dry branches or remnants of hranches is not, as a rule, conducive to any danger to the life or heallh of the tree, provided the operation be carried out in a careful way. On the contrary, it often reduces the danger from rot, because it facilitates the process of occlusion, or covering over of the wound by layers of new wood. Matters are different in the case of green brandies. Here the wound caused by the removal of the branch frequently causes rot, because the unprotected open wound offers a tit germinat- ing bed for the spores (jf fungi ; the wound, on drying, opens out in rents and cracks, into which rain water may carry the spores ; the latter germinate and cause decomposition, which spreads and reduces the value of the stem, or may entirely destroy it. Several dangerous parasitic and saprophitic species of fungi thus enter trees. PRUNING. 285 It is essential, therefore, that the wound should be closed as quickly as possible and made impermeable to the spores of fungi and to water. This is effected liy nature through the process of occlusion, provided the wound does not exceed a certain size. The time required for this operation depends on the size of the wound, the vigour of the tree, the manner in which the wound is made, and above all the species. Pruning green branches is least dangerous and objectionable in the case of oak and most conifers which are in vigorous health, provided the operation is carefully done and the wound does not exceed 3 inches in diameter. Oak closes the wound rapidly by occlusion, while wounds on conifers exude turpen- tine, which protects them to a considerable extent. As regards other European species the evidence is at present conflicting. Pruning green branches of poplars, birch and willows is undesirable, because their wood is liable to rot quickly. According to Hess some of the important species may be arranged in the following descending series in respect of the activity of occlusion : — Broad leaved speeiea : Oak, beech, hornbeam, lime, ash, maple, birch. Conifers : larch, silver lir, Scotch pine, spruce. In the case of the last- mentioned species the pruning away of green branches is, in the opinion of most foresters, altogether undesirable. Under any circumstances, the pruning of green branches should not be undertaken without due consideration of the advantages which are likely to be realised and the dis- advantages connected with the operation; this is of special importance in all cases where the objects of management centre in the production of large sized timber, which can only be obtained by permitting the trees to grow and increase for many years after the pruning has been carried out. 3. Execution of Pruning. Where the object is to produce valuable timber trees, the branches should in all cases be cut off close to the main stem, but without injuring the bark of the latter ; only in this way 286 TENDING OF CROWDED WOODS AFTER EARLY YOUTH. can quick occlusion of the wound be expected. If the object be merely to relieve yount; growth of cover overhead, the above rule may lie neglected. The work may be done with the knife, hatchet, billhook, shears, or saw. Cutting instruments produce a smoother surface of the wound, but, unless very carefully handled, injuries to the bark of the main stem are likely to occur. The saw [)i-oduces a less smooth surface, but, if carefully handled, it does no injury beyond the actual cut. Heavy branches should first be cut oti' a short distance from the stem, and then, by a second cut, the remaining stump should be removed, to ensure the production of an even cut and to avoid tearing the bark of the main stem. Saws are used, either in connection with a light ladder, or they are placed on poles. In the first case pruning can be carried out to a considerable height. Saws placed on poles are only effective up to a moderate height, VI to 18 feet. Of hatchets, that constructed by Courval (Fig. 82) is speci- ally recommended. Fig. 83 represents a pushing chisel, with which branches can be removed up to a moderate height. Fig. 84 is a bow-less saw, and Fig. 85 an ordinary hand saw. Fig. 86 is a saw in the shape of a bayonet fastened on a pole, designed by the author ; it cuts with the downward stroke. Fig. 87 represents Aider's pruning saw, which is also fastened to a pole. The two last mentioned are specially recommended, where the use of a ladder is not preferred. Wounds, which are so large that they are not likely to be speedily closed by occlusion, must receive a waterproof cover- ing; this is necessary even in pruning large branches of coniferous trees. The most suitable covering consists of a layer of coal tar, made sufficiently fluid by an addition of oil of turpentine, and laid on with a brush. The artificial covering will only stick on when the sap is down ; hence, in temperate Europe the best time for pruning is autunni and the first half of winter. Dry branches and snags may be cut off at any time of the year. PRUNING. 287 Fig. 82. Fig. S3 Fig. 84. ^ Fiff. Hr Fi- 86. Fig. 87 288 TENDING OF CROWDED WOODS AFTER EARLY YOUTH. provided tlie living tissue of the tree is not injured durinp; the operation. According to R. Hartig pruning green branches while the tree is in sap causes a somewhat rapid decomposition of the wood near the wound. For this reason also pruning in tlie first lialf of winter is recommended. Section III. — Thinning. 1. General. One of the most important objects in the formation of a wood is to stock the area sufficiently, so that a complete cover overhead may be established as early as possible. This is desirable, not only for the preservation of the soil, but also for a i)roper development of the trees. In order t) ensure quick closing overhead it is necessary to bring on to the ground a much larger number of plants than can find room on it for any prolonged period. Soon after a complete leaf canopy has been "established, the trees commence pressing one against the other, there is not enough growing space for all, and then a stri(;/(ile for existe)ice sets in. A portion of the trees outgrow the rest, and they rear their heads up to the full enjoyment of the light. Between and below them are the rest of the trees ; some of these still enjoy with their leading shoots light from above, though they are already dominated trees ; others have been already left behind to such an extent that they are actually dei)rived of the direct enjoyment of light, in other words they are suppressed ; they live on for a shorter or longer period according to species and other circumstances, and then die. Thus there are four classes of trees, namely : — (1.) Dominating trees. (2.) Dominated trees. (3.) Suppressed trees. (4.) Dead and dying trees. This struggle, if not interfered with, continues whilst height growth lasts, and it gradually reduces the growing space of each dominating tree to such an extent, that the hitter cannot THINNING. 289 develop in the most advantageous manner ; consequently such trees are likely to assume a thin, lanky shape, so that they are frequently unable to stand upright, if deprived of the support of their immediate neighbours. They are liable to be ])ent and broken by wind, snow, or rime. To obviate such a state of affairs the forester interferes in good time by removing a portion of the trees ; he tit ins the wood. Thinnings, then, are cuttings, which have for their object to provide for each tree left standing that growing space, which is best suited for its further development according to the objects of manage- ment. It is necessary to exj^lain this somewhat in detail. 2. TJtc most suitable Groiiing Space. As the objects of management differ, so must the most suitable growing space. A})art from this the growing space differs according to the age of the wood, the species, the soil, elevation and aspect of the localit3\ a. Objects of Management. A tree growing in a free position, in complete enjoyment of vertical and lateral light, will develop a full crown and root system, and lay on a maximum of volume. This is no doubt a great point, but it is counterbalanced by serious drawbacks : — In the first place a wood grown in this fashion does by no means always produce the greatest volume per acre, as the total production is represented by the average volume per tree multiplied by the number of trees per acre. Although each tree in a crowded wood has a smaller volume than one grown isolated, yet, owing to the greater number of trees per acre, a crowded wood may have, and generally has, a greater total volume per acre than one in which the trees grow isolated. Secondly, isolated trees are liable to suffer in height growth and in straightness. In the third place, such trees are frequently covered with branches low down, and in consequence they produce less valuable timber. In the case of conifers the timber is also liable to be of an inferior quality, owing to the greater breadth of the concentric rings. Last, but not least, •2t>() TENDIN(; OF CHOWDKl) WOODS AFTKU KAlUA' YOUTH. open woods cannot preserve the fertility of the locaHty ; hence they are only admissible on fertile localities, or special measures must be taken to preserve the fertility of the soil. These considerations govern the most profitable growing space in any particular case. It is conceivable tliat under certain condilions tlie con-f^ct policy is to i-cniove all dead, suppressed, and dominated trees, and even a portion of the dominating trees, while in others the dominated and even suppressed trees may have to be carefully husbanded, so as to realise the objects of management in the highest possible degree. Ii. A I It' I if Wood As the number of trees per acre decreases gradually from several thousands to a comparativel}' small number at maturity, it follows that the growing space increases with advancing age, though not evenly. Statistics collected on this point in Germany gave the following results foi- pure woods of Scotch pine, spruce and beech, grown on soils of lirst quality : — Age of Wood, ill yeai-s. Numbei- of Trees, pel- .acre. Mean Orowiiig Space per Tree, in square feet. Decrease in the Number of Trees during 20 Years. Increase of Grow ing Si»ce i«r Tree, iu per Cent. L.ScofrhPini': 20 40 1.420 720 80) (10 J 700 100 (id 870 ) llSj 8.-.0 'J 7 S(l 280 ) IS'.tj 140 60 Kin 170 1 2.-.G) l°>() 8.-. 11. S,>r,rr: ■JO LI 80 l.->| 8!)/ 1.840 100 (10 510 ) 8^1 (•.20 118 .SO 810 14l| 200 (u; 100 220 l'..S) •.)o 40 111. JWr/,: 20 4(1 2,:.:)0 '.MO 4(;i Fcio 171 CO 428 1 108, .-.17 124 SO 24'.) 1 1 7', i 171 70 100 l('>(i 2«2/ 88 r.o THE MOST SUITABLE GROWING SPACE. 291 These data show that : (1.) The increased requirement of space is very great between the ages of 20 and 40 years; it then falls gradually up to the age of 100 years. (2.) Many trees must be removed during the earlier part of a wood's life, and comparatively few later on, always assuming that the area is to remain fully stocked. r. Speries. Light demanding species require more space than shade bearers ; broad-leaved species more than conifers. The above table shows that the light demanding Scotch pine requires considerably more growing space than the shade bearing spruce ; the latter less than the still greater shade bearer the beech. Comparing the growing space of Scotch pine, larch, oak, and birch with that of spruce, beech, and silver fir, the pro- portion is about 100 to 65. : Allitude. Under otherwise equal conditions the number of trees per acre increases with altitude, at any rate up to a certain eleva- tion. The statistics of the Black Forest for the three regions approximately indicated as below 1,200, 1,200 — 2,100, and 2,400 — 3,600 feet, showed the following proportion in the number of trees : — 100, 126, 244, This law could not be established above 3,600 feet, because at that height regular woods disappeared. It was farther noticed that the difference is more pronounced in the case of shade bearing species and u 2 ^02 TENDING OF CROWDKl) WOODS AFTKU EARLY YOUTH. during the earlier part of life, tliaii in the case of li^^ht demanding species and latei" on in life. /'. .\s/ic< Thnhcr. Where the production of high-class timber is aimed at, quantity must to some extent be sacrificed. Trees fit to yield such timber must answer the following description : — (1.) The boles must be tall, straight, free of branches, and as litt'e tapering as possible. (2.) Differences in the breadth of the concentric rings must be slight. (3.) The timber must have a high degree of density. Boles free from branches and non-tapei'ing are not produced, if heavy thinnings are made at an early age of the wood ; at any rate not in the same degree as if the wood were kept dense, when the lower branches are more rapidly killed for want of light. Pruning cannot make up for this, though it can do something. There is naturally a tendency to produce broader rings during youth than later on ; heavy thinning at an early age 29(\ TENDING OF CROWDED WOODS AFTER EAUEY YOUTH. increases the ilitYerence, leading to the formation of trunks whicli consist of a niimher of broad rin^^'s in the inner i)art, surroinided by a series of narrow ones. Such timber is for many purposes of smaller value than if the rings are of uniform breadth throughout. As regards the density of the timber, a distinction must be made between the various species. In the case of those broad leaved species which have the pores in the spring portion of the wood, broad rings indicate high density, and narrow rings comparatively low density ; here, then, heav^y thinnings are indicated. The same prol)ably holds good for species which have the pores uniformly distributed over the ring. In coni- fers, however, the matter is reversed, as in their case broad rings usually represent low density and narrow rings high density ; consequently heavy thinnings must be avoided, at any rate up to a certain age. On the whole it may be said that, in the production of higli-class timber, heavy thinnings at an early age should be avoided. The rule here, according to which the thinnings are to be made, must run as follows : — The wood sliould be thinned lightly until towards the end of the principal height growth. Then the thinnings should gradually become heavier, so as to assist a selected number of trees by the gradual removal of all those which are inferior and diseased ; in other words, the thinning is then done more in the dominating and dominated trees than in those which have been left behind in the struggle for existence and no longer compete ; the latter, if capable of living on, may be left to assist in the protection of the soil or to act as wind brakes. This method of thinning is called " eclaircie par le haut " in French, and " Hochdurchforstung " in German. 4. TJiiintiiKi of Mixed ll^oods. In the foregoing pages the theory of thinning as applicaljle to pure woods has been given. Generally, the points aimed at are to stimulate producticm and to develop the most suitable THINNING OF MIXED WOODS. 297 individuals for the final crop. In mixed woods a third con- sideration iDresents' itself in the preservation of a suitable mixture without interfering with the maintenance of a sufficient leaf canopy ; this often leads to deviations from the theory as indicated above. In the case of mixed woods it may often be necessary to remove a dominating tree of one species, because it threatens to suppress a tree of another species, which must be preserved for the sake of the mixture. To guard against an interruption of the cover in such cases the dominated and even suppressed trees must be more carefully husbanded than in pure woods, until, with the advancing age of the wood, the mixture has l)een secured. Frequent and light thinnings are in such cases indicated. Their actual degree depends much on the light requirements of the more valuable species in mixture. The operation is facilitated if the several species are mixed by groups instead of by alternating single trees. Where a valuable timber species is mixed with a less valuable one, the former must be favoured from an early age, so as to bring it to the highest possible development, if neces- sary at the expense of the less valuable species. As long as the valuable species is of quicker growth than the other, the operation is comparatively simple ; but if it is of slower growth, all individuals of the secondary species which threaten to over- top it must be cut away, until the principal species is secure. 5. Tliinniiig of Coppice Woods. These thinnings are conducted according to the same principles as in high forest, whenever the number of shoots is so great that there is not enough growing space for all. More especially in oak coppice the quality and quantity of bark may be considerably influenced by leaving on each stool only the two or three best shoots and removing the others. Such thinnings are generally made in the second half of the rotation. In coppice with standards, such thinnings are frequently required to set free seedling plants growing amongst the coppice. :2V' s TENDING (»F CROWDED WOODS AFTER EARLY YOUTH. tl. Principal Adnitttafics of Thinninfis. The principal advantages of thiDiiings are as follows: — (a.) They afford the means of guiding the development of a wood in accordance with the objects of management, either by producing the iireatest possible quantity, or the best possible quality of produce ; in some cases l>oth these objects may be combined. (b.> They afford the means of preserving a suitable mixture in the case of mixed woods, (c.) Danger from insects, fungi, and fire is greatly reduced by the prompt removal of dead and sick trees, (d.) They afford the means of strengthening the trees destined for the final crop against damage by snow, rime and wind, (e.) They yield substantial early returns. The returns from thinnings should not be under-estimated, especially where the object of management centres in the production of quantity. According to the yield tables of Weise, Scotch pine may be expected to yield the following returns under a rotation of 100 vears : — Quality Cla^ of Locality. ri'H-:-> JE s:.".:i: cubic fe#t perj Intermediate Retoms, or Final BeTorii*. Thinnins*. oTInto-- Tw^li^t^ to Final ! Total. B*ain»*, in n WT C*nt. A.—rtmher and Fagots. I„ or best II., or middling III., or worst . . ^ 4..>80 2.4 7«« III .^2 41 17 B.— r,mber of 3 infhc* diametrr ami Kptrard* ami if. I n Ill 3,370 1,820 250 8.130 5.330 2.420 11.300 7.15f» 2.670 41 34 11 Similar infoimation regarding the yield of thinnings in spruce, silver fir and beech woods will be foimd in Volume III. EXECUTION OF THINNINGS. 299 7. Exeaition of Thiuninfis. The advantages of thinnings can l)e fully realised only if the operations are conducted in a careful and judicious manner ; in other words they must he attended to by a competent forester and not left to the wood-cutters. In young woods, which have as yet a large number of trees per acre, thinnings should generally be carried out in the presence of a competent forester ; only where the wood is absolutely uniform throughout, a sample may be prepared as a guidance for the workmen, and this only if the latter are thoroughly reliable and competent. In the more advanced stages of life each tree to be removed should be marked separately and in the forester's presence, and this should be done while the trees are in leaf, so that the effect of the removal may be properly judged. Special care is necessary where valuable timber trees are to be produced, where domi- nating trees are to be removed, and where a proper mixture of species is to be preserved. The exposed edges of a wood should be thinned heavily from an early age onward, so that the remaining trees may retain their lower branches, and thus be trained to withstand strong winds. If the wood be subject to the effects of raw, cold, or dry, hot winds, the exposed edge should be kept as dense as possible, and an additional strip some distance from it may be kept in a similar condition. The best time for the execution of thinnings is winter, but local circumstances demand deviations from this rule. In high mountains they must be done in summer, as the localities are generally inaccessible during winter. ;i(i() ('RAPTKK III. TENDING OF OPEN WOODS FOR THE PRODUCTION OF LARGE TIMBER. 1. Thr Theori/. In the foregoing chapter it lias been shown how thinnings should he conducted, if the principal part of a wood — the dominating trees — are to be given increased space and enjoy- ment of light, followed by increased increment, without, how- ever, interrupting the leaf canopy to such an extent as to affect injuriously the continued activity of the soil. Under this method of treatment the one aim acts antagonistically to the other, and it is by no meanf^ easy to conciliate the two interests. Hence the problem presents itself, whether the better portion of the dominating trees cannot be more com- pletely isolated, while the soil is protected by other means. There are other considerations whicli press the subject upon the attention of the forester. Under the ordinary system, as described above, the production of large sized timber demands a higli rotation, and any measures which tend to reduce tlie latter must be welcome. Experience has shown that by isolating the trees, timber of a certain size can be produced in little more than half the time required under tlie method of continuously crowded woods. Anotiier point is, that man}', and more especially the light demanding, species have a natural tendency to open out, or to form large crowns. It is of additional importance that under a system of heavy thiimings, considerably larger intermediate yields are obtained early in the rotation. This, in conjunction with the more rapid development of the trees constituting llic liiial cio]). leads to more favourable Ihiancial results. THE THEORY. 301 On the other hand, the early isolation of a portion of the trees has weighty drawhacks. In the case of many species it affects injuriously the height growth of the trees. Then, isolated trees maintain their side branches low^ down, and even develop fresh ones, which for many purposes seriously reduce the value of the stems. In the case of conifers the quality of timber also may be lower, owung to the formation of exceptionally broad concentric rings. Isolated trees are further liable to form more tapering boles than those grown in crowded woods. Above all, in the majority of cases a suffi- cient layer of humus cannot be preserved, its place being taken by weeds. Moreover, a suital^ie degree of moisture cannot be maintained. It follows that, except on really fertile soils, other means must be devised to preserve the continued activity of the soil. This is done by the introduction of an underwood, or soil protection wood. But even then it is found that the extra diameter increment, laid on after isolating the trees, will hold out only on soils of some quality, while on indifferent soils it will, after a few years, sink back to its previous amount. The general theory of the method of treatment in the case under consideration may be shortly described as follows : — Commencing with the first thinnings the most promising trees are singled out, and these are isolated sufficiently by increasingly heavy thinnings, so as to permit the introduction of an underwood. As soon as the latter has established itself, and is capable of protecting the soil, a further heavy thinning is made, by which the remaining trees are completely isolated. Subsequently more thinnings follow, as required by the extension of the crowns of the trees. The underwood can be established in a variety of ways, such as by sowing or planting, by natural seeding, or by coppicing a portion of the overwood. In some cases the underwood itself is allowed to grow into timber trees (two- storied high forest) ; in others it remains a soil protection wood. 802 TENDIXr, OF OPEN WOODS FOR LARGE TIMBER. The pnx'cdure differs coiisideral)!}' according to species and the ol)jects of management. To meet the special requirements of each case a considerahle numher of modifications have been ehiborated. Some of these commence with tlie isohition in early growth, while others during the greater part of the rotation follow the system described in the last chapter, and reserve to its latter part the isolation of the more valuable trees. Although the treatment has been recommended for almost all species, it is eas\' to perceive that thinly crowned species, which are generally light demanding, are better adapted for the method than those with a dense crown, as the underwood has a better chance of thriving under the former, and doing justice to the task which it is called upon to perform. In Britain the oak, larch, and Scotch pine have, in a rough way, been treated according to this method for a long time past. On the Continent the treatment has been elaborated in comparatively recent times. 2. I'riiicijial Foniis . Isdhttidii of a fi'ir Srlirlnl Tiers, irilhoiif C inlcnroinl. A limited number of selected trees are placed in a free position, by removing all surrounding trees which threaten to interfere with them. The system should be applied only in case the nuiin part of the wood consists of a species with full crowns, and where the selected trees are of (juicker height growth than the rest. To avoid loss of height growth and the retention of low side bi-iuiches, the operation sliould not be commenced until towards the end of the period of principal height growth. The treatment is specially adapted to mixed woods of beech and light deniaiidiiig broad leaved s[)ecies, such as oak. ash, and elm. PRINCIPAL FORMS OF TREATMENT. 303 b. Prolongatiiiii of the Ratjeiipratioa Period under the Shelter-wood Systems. Woods treated under artificial or natural regeneration under a shelter-wood offer excellent opportunities for the realisation of the extra increment due to an isolated position of a limited number of trees. In the same degree as the shelter-wood is thinned out by successive cuttings, the remaining trees profit by accelerated increment ; the process can be further extended by retaining a limited number of trees for an extra term of years, or by prolonging the regeneration period. The method is specially adapted to thin crowned, wind firm trees. Shallow rooted trees are likely to be thrown by wind. The injurious effect of trees with crowns coming low down upon the young growth must be mitigated by pruning away their lower branches. c. lletention of Standards in Hiyh Forest. A limited number of the most suitable trees are, after the wood has been regenerated, retained as standards for part or the whole of the second rotation, and in some cases even for a third rotation. Only wind firm species are thoroughly suited for such treatment, and they should moreover be thin crowned. The number of standards depends on the density of their crown and the quality of the soil ; only perfectly healthy well-formed trees should be chosen, especially those which have cleared themselves of branches to some height, to obviate the necessity of pruning. The tending of the proposed standards may usefully be commenced some time before the end of the first rotation, as indicated under a. d. Isolation of Trees in Conjunction a-ith an Underwood. A wood is uniformly thinned, and an underwood is formed by sowing, planting, natural seeding, or by coppicing a portion of the overwood. Thoroughly satisfactory results are obtained only if the overwood consists of thin crowned and the y04 tp:ni)Ing of open avoods for lai{(;k timrkk. underwood of shade beurinj]; species. In temperate Europe, oak, ash, ehn, hirch, and Scotch i)ine are the species specially suited for the overwood, and beech, hornbeam, silver iir, spruce, and in some cases Douglas fir, Weymouth i)ine, sweet chestnut and hazel for the underwood. Sometimes the under- wood is itself allowed to grow up into trees ; in other cases, when consisting of broad leaved species, it is treated only as a soil protection wood, and is periodically coppiced. Beech makes the best underwood, as it bears much shade and improves the soil more than any other species. Silver fir comes near it. Hornbeam is best in frost localities. Spruce should be used only in fresh localities, as on dry soil it may cause the overwood to fall off in growth. Where the underwood is permitted to attain the size of timber trees, it is cut with the overwood ; the latter may, how- ever, ])e retained for two rotations of tlie underwood, thus producing specially large timber. A few remarks on the tending of the more important species will further illustrate the method. i. Oak as OvEiiwodi). A fully stocked oak wood is, when the projter time has arrived, thinned rather heavily at frequent intervals, say every 5 to 10 years, according to the locality ; during these operations all trees with a tendency to lag behind are removed, as well as ill-shapen and diseased trees. At the age of 30 to 60 years, according to circumstances, a specially heavy thinning is made and the underwood started, beech being best for the pur])ose. When the underwood has established itself, say 10 to 15 years afterwards, another heavy thinning is made, by which the remaining trees are isolated. Subse- quently more thinnings follow, at moderate intervals, in the same degree, as the oaks develo}) and llireaten to close up again. It is estimated tiuit in this way about 50 oak trees per acre can be made to reach a diameter in 120 vears, which THE IMPORTANT SPECIES. 305 in a fully stocked wood they would reach in about 200 years. ii. Lakch as Ovekwood. This being a quicker growing and shorter lived tree than oak, the first specially heavy thinning and underplanting may be done between the 15th and 30th year. The underwood should consist of beech. Silver fir is also recommended, but it grows slowly during the early part of its life. Another species suitable for underplanting may be found in the Douglas fir. Possibly Weymouth pine may answer. The two last-mentioned species are of quick growth. In this manner about 75 larch trees per acre may be brought to large timber size in 60 to 80 years. iii. Scotch Pine as Over-wood. The heavy thinning and underplanting may take place between the 20th and 40th year. Beech is an excellent under- wood, but spruce is also admissible in this case. Douglas fir and Weymouth pine may do, where the locality is suitable. The last-mentioned species grow so rapidly, that they will reach timber size at the same time as the Scotch pine. iv. Otiieii Species as Overwood. Ash, elm and sweet chestnut may be treated in a manner similar to that indicated for oak. Various other species, such as spruce, silver fir and beech, either pure or mixed, have been tried and recommended for treatment under this method, but it would be beyond the scope of this manual to enter into a discussion of the question, under what conditions and in how far they are suited for the purpose. 3. Execution of tJic If^orA". The selection of the trees for removal must be most care- fully considered, as mistakes made in this respect are difficult to rectify. The main point is, that almost from the first thinning the trees likely to form the final crop are favoured «• X 306 TENDING OF OPEN WOODS FOK LARGE TIMBER. and trained for their ultimate purpose. They should consist of the i>est trees which are likely to develop into line, valuable timber trees of large size ; to enable this favoured portion of the wood to reach such proportions in the shortest possible time, mucli of the rest of the wood must be sacrificed. This should not be done, unless the sacrifice is more than covered by the special excellence of the final crop, a case which can be expected to occur only on fairly favourable localities, which insure a special increment of the isolated trees during a considerable period of time. 307 PAKT IV. SYLVICULTURAL NOTES ON BRITISH FOREST TREES. x2 309 SYLYICULTUEAL NOTES OX BEITISH FOREST TREES. The theoiy and practice of sylviculture, as described in this work, have been ilhistrated by instances taken from the more important forest trees grown in temperate Europe. For the sake of reference, it will be found useful to bring these scat- tered remarks, and other information, together in a set of notes on each of the trees which are of real sylvicultural importance in Great Britain and Ireland. The trees naturally arrange themselves into two groups, the broad leaved and coniferous species. Of each group the important shade bearers have been placed first, as the notes on the light demanders depended on those referring to the former. Generally, the notes have been made as short as possible ; if a full account of each tree had been given, this part would have attained the size of a book. Apart from the author's own experience, they have been derived from the best authorities. The following explanations will be useful : — (1.) The average specific gravity of air dried wood has been taken from Hess's " Die Eigenschaften und das forstliche Yerhalten der wichtigeren in Deutschland vorkommenden Holzarten.'' (•2.) By volume increment is here understood the mean annual production per acre in crowded woods calcu- lated from the increment of the most favourable rotation. (3.) The information about insects refers principal!}- to Britain. 8]<) NOTKS ON HIUTISH FOKKST THKKS. 1. J3bkcii — Fi si/lnitira (L.). n. mm If. ]3eech yields excellent firewood and very good cliarcoal. The timber is not of much vahie wliere strength and durabilit}' are wanted ; it is brittle and short grained. Specific gravity, air dried, on an average = "74. Under water it lasts well. Formerly the timber was much used in machinery, especially by millwrights ; nowadays iron has replaced it for many purposes. Beech M'ood is still used for furniture, in carpentr}', turnery, etc., more especially for the manufacture of chairs in Buckinghamshire and adjoining counties. On the Continent it is much used for packing cases, barrels, wooden shoes (sabots) and heels of ladies' boots. It is used also for railway sleepers, after treatment with antiseptics. The leaves are used for litter, the nuts as fodder for pigs and deer ; the seeds yield a superior oil. The wood is rich in potash. //. /Ji.s/n'buliaii. It is found in temperate Europe from Norway to the Mediterranean, or between the 40th and GOtli degree of latitude, also in Western Asia ; it is apparentl}' indigenous in England, and found planted in Scotland and Ireland. It is a tree of the lower mountains and plains ; going up to about 700 feet in Norway, 1,200 feet in Derbyshire, 4,500 feet in the Alps, and over 0,000 feet on IMount Etna. r. LardHli/. Climate. — lieecli is fairly hardy as regards wiiilcr frosL l»ut very sensitive to late sprhig frosts, wliidi. during early youth, frequently injure or- even kill it. It stands more shade than any other indigenous broad leaved species, but somewhat less than silver fir. It requires a fair amount of moisture in the air, hence it grows well in the vicinity of the sea and on northern and eastern aspects, while it disai)pears in the eastern part of Europe owing to the drier continental climate. It is liable to l)e thrown by strong winds, but not to aiiv excessive extent. THE BEECH. 311 Soil. — Beech requires a soil which is at least of middling depth, of a moderate degree of porosity, fresh and fertile ; it thrives best on loamy soils, and especially on marls, and on calcareous soils generally ; also on sandy soils, provided they are thoroughly fresh and contain water at a moderate depth in the subsoil. Wet soils are unsuited, and inundations fatal, to beech. //. Sk((po and Dei'f'loimienf. The stem of the beech divides, as a rule, only in the upper part ; the crown remains oval until towards the end of the principal height growth, when it becomes flat or rounded off at the top. Owing to its shade bearing power, the crown extends far down the stem, if grown in the open. In crowded woods, the crown occupies about the upper third of the height of the tree. The root system extends to a moderate depth, the tap-root being of no importance after the first 5 or 6 years. Beech is of slow height growth during the first years of life, compared with other broad leaved species ; when from 20 to 30 years old, the rate of height growth increases, so that it outgrows the other broad leaved indigenous species, as a rule also the oak, reaching an ultimate height of about 110 feet, and under specially favourable conditions considerably more. In Normandy trees up to 170 feet high have been measured. Spruce, silver fir, larch, Weymouth pine, and Douglas fir attain, under ordinary conditions, a greater height than beech, though the silver fir grows slower during early youth. The volume increment of beech is greater than that of the other indigenous broad leaved species, but smaller than that of the principal conifers. According to the latest yield tables the total production of timber and firewood in the course of 100 years, on a locality of the first quality, should be, in the case of : — Silver fir . = 23890 c' Scotch pine . . = 18170 c' Spruce = 22180 „ Oak . . = 12730 „ Beech . . = lo230„ :Ui NOTKS ON IWill'lSH FOREST THKES. If grown in crowded woods, l)eecli rarely reaches an age of more than 200 years ; in the open, it attains a much greater age. I'. Hi'piOihii liri' I'liirrr. I3eech commences producing full crops of good seed at the age of ahout 60 years; it yields heavy crops, but full masts cannot be counted on at shorter intervals than 5 years, and often 10 to 15 j^ears, according to local circumstances ; partial masts occur during the intervals. Taking both factors together, the reproduction of beech by seed is less favourable than that of most other indigenous species. Reproduction from the stool is feeble, as compared with other broad leaved species ; it ceases after the age of 40 j^ears, and the stools rarely last for more than three or four rotations ; it is best on marls. /. ('Iidrdclcr itiiil CoiiijXisiliiin af Wnods. Beech is eniinenll}' adapted for growing in })ure woods, since it shades the soil thoroughly up to an advanced age, maintains and even improves its fertility, and bears much sliadi . For the same reasons it is e(iually well adapted to t'urui the principal constituent of mixed woods. Probably no other species equals it in this respect. Trees like oak, ash, maple, elm, silver lir, Scotch pine, larch, and also spruce thrive best when mixed with beech ; in fact this is the case with almost any species which thrive; on localities suitable for beech. //. Siilriiiilhiidl Si/slcinf<. ]3eecli is specially ada[)ted for high forest. It is less well suited for coppice woods, owing to its feeble reproductive power from the stool. It iip[)oars as underwood in coppice with standards. In high forest the rotation should range between HO and 120 years, in coppice between 20 and 35 years. In high forest it is grown in even aged and uneven aged woods ; lar-'e areas are treated as selection woods THE BEECH. 'U-'i (Buckinghamshire). It is the best species for underplantiiig open woods of valuable timber trees. h. Formdtioii af Woods. Beech is specially adapted for natural regeneration by seed under shelter-woods, if the cuttings are arranged in a suitable manner. Direct sowing and planting can also be done, but the young crop must be sheltered whenever late frosts and (brought are apprehended. The seed ripens in October, and falls shortly afterwards, retaining its germinating power for about six months. Up to 80 or 90 per cent, have been found to germinate, but it is con- sidered good seed if at least 50 per cent, germinate. One pound of seed contains, on an average, about 2,000 nuts. Direct sowings may be made in autumn, or spring ; in the former case the seeds are liable to attacks by animals, and the seedlings, owing to their early sprouting, to damage by spring frosts ; in the latter case the nuts must be kept in an airy place or shed, and turned over periodically (during dry weather towards spring it may be slightly sprinkled with water to prevent drying up). If sown in spring, the nuts sprout after four to six weeks. About 150 pounds of seed per acre are required for broad-cast sowings, and propor- tionally less for partial sowings. The nuts receive a covering of three-quarters of an inch on soil of middling density, some- what more on loose and a little less on heavy soil. In nurseries, the seed is generally sown in drills. The seed- lings may be left in the seed bed for two .years, when they are pricked out in lines, the latter being from 12 to 24 inches apart, and the plants in the lines from 4 to 8 inches. When the plants have stood two years in the lines, being then altogether four years old, they are ready for putting out into the forest. They are usually planted in pits from 3 to 4 feet apart. For underplanting, two years old seedlings are frequently used. As a general rule, the seedlings and young plants require protection in the nursery against frost as well as against hot sun. :i\4- NOTES ON HHITISII I'OHEST TltKKS. It is not desirable to prune beecli plants. The process of natural regeneration under a shelter-wood is, on the whole, slow ; one or more preparatory cuttings are required, and if the soil be not sufficiently prepared at the advent of a seed year, it must be worked (wounded) ; this is best done by light hoeing ; the seeding cutting is compara- tively light, and the cuttings in the final stage are regulated by the character of the locality and the requirements of the young crop. Under favourable circumstances the whole regeneration period may be completed in 10 years, but frequently extends to 20 years and even more. i. TcntJiiKj. Fertiliiii of the Soil. — Fully stocked beech woods preserve and even improve the fertility of the soil to a greater extent tlian any other species, owing to their dense foliage up to an advanced age, and the heavy fall of leaves. External Dangers. — Late frosts are the greatest enemy of beech ; during early youth they kill or seriously damage the plants, and even later on the tender parts of the tree are liable to suffer ; hence it must be raised under shelter, which is provided either by the old crop, or by a special shelter- wood of hardy species, such as Scotch pine, birch, and larch ; Austrian pine will also do. In natural regenerations, the edges of the shelter-wood must be kept as dense as pos- sible to afford protection against cold winds. In tlic culti- vation of blanks, artificial shelter belts must be grown some years beforehand, on the side whence the cold winds l)low. ]3eech suffers also from drought while young. Later on it is more than any other species exposed to blistering of the bark by the sun ; the bark is also separated from the wood, if struck by the morning sun after a heavy niglil frost ; hence it is not well suited for standards, apart t'roiu (lie heavy cover which the tree gives. Storms, snow and rime are (mly to a limited extent liiiilful in l)eech woods. THE HORNBEAM. 3L5 Cattle and game like to browse beecli ; red deer, hares, rabbits and mice peel off the bark. Insects rarely do much damage. The leaves are devoured by lepidopterous larvse, especially those of DasycJiira pndibunda, and HaJias j^rasinaiia, and sometimes the polyphagous Llparis monaclia, as well as by the weevil Orchestes fagi. An ajDhis, Cri/ptocorcus faiji, sometimes kills old trees. The freshly cut timber is liable to the attacks of Tomicidte, and other boring beetles. Of fungi, Pliytophtliora omnivora destroys young seedlings ; where it appears in large quantities, seedlings cannot be raised for 5 to 8 years, hence nurseries must be changed, or used for other species. Nectria ditissima causes canker on the stem, which may, however, also be the consequence of frost. The so-called green rot is due to Peziza ceruginosa. Priuiiitg.— Beech stands pruning better than most other species, but it is rarely, if ever, done unless the shade injures other more valuable timber trees. Thinnings are commenced at the age of 25 to 40 years, according to locality ; they should be at first moderate, after- wards heavy. 2. Hornbeam — Carpiniis Befulus (L.). a. Ufili///. The hard and heavy wood is an excellent fuel, and it yields good charcoal. The timber is very tough, and is used in machinery by the millwright, for wheels, and a variety of other purposes. Specific gravity of air dried wood = "75. The ashes are rich in potash. The leaves yield good fodder. I). Distribution. It is found in temperate Europe up to the 60th degree of latitude. Indigenous in England ; planted in Scotland and Ireland. Goes up to 1,200 feet in the Harz Mountains, and to about 3,000 feet in the Alps ; generally a tree of the low lands and low hills. .'316 NOTES ON RHITISH I'OHKST THKKS. r. LoikUIij. Cliiiuitr. — The hornbeam requires only a moderate tempera- ture, and thrives even in cold moist localities unsuited for beech. It is one of the most frost hardy species, hut rather tender as regards summer heat. It stands a considerable amount of shade, but not so much as beech. It seems to require a moderately moist atmosphere, and prefers north and east aspects. It is to some extent lial)le to be thrown by wind, but resists snow uiul rime ratliei' well. Soil. — Hornbeam likes a soil which is somewhat loose, of at least middling depth, thoroughl}' fresh if not moist, and minerally rich. As regards moisture, it stands between beech and ash, and in respect of mineral matter in the soil it is not quite so exacting as beech. Loams, sandy soils rich in liunnis, and marls suit it best ; here it attains its full development. At the same time it is found on dry soils, though of inferior development, and on heavy clay soils ; it frequently replaces beech in heavy soils and in frost localities. (/. S//{i/)e ami hcrflo/nnriil. The stem of the hornbtuini is generally divided into branches comparatively low down. The general shape of the tree, if grown in a favourable locality, approaches that of the beech ; on inferior soils it sinks down to an insigniticant tree, witli a short bole and large crown. The root system on the whole is not deep going ; there are strong side roots which reach a moderate depth. It grows somewhat quicker than beech during the Ihst years of life, but it rarely reaches a total height of more than 75 feet. Its volume inerement is considerably smaller than that of beech ; nor is hoinbeani so long lived as the latter. f. Urinodiiclirr I'dii'cr. Hoinbeani commences beai'ing full crojjs of seed when about -10 years old, and it seeds plentifully almost every year. THE HORNBEAM. 317 at any rate every other 3'ear, so that its power of reproduction by seed is on the whole great. The reproduction from the stool is excellent ; the shoots appear at any part which has been coppiced. The stools last for hundreds of years ; the tree is eminently suited for pollarding. /. Clutrarh'T (ind Coiii/wsifio/i. of Woo/Is. Hornbeam appears in pure woods in Eastern Europe, and also in England (Epping Forest). It is not equal to beech in its capacity for improving the fertility of the soil, since it has a lighter foliage, does not maintain a cover overhead so long, and does not bear so much shade ; the leaves also decompose more rapidly than those of beech. At the same time, it stands next to beech in this respect amongst broad leaved species, and may replace it in localities unsuited for beech. Hornbeam appears chiefly in mixture with beech and oak, but also, like the beech, with other species, but not to the same extent. //. Sijlvkiiltaral SijstemH. Hornbeam can be grown as high forest, coppice, or pollards. It appears as underwood in coppice with standards, and makes an excellent soil protection wood in open woods of valuable timber trees. It also makes excellent hedges. As high forest, it would generally be treated under a rotation not exceeding 100 years, as coppice from 15 to 35 years, and as pollards from 5 to 10 years. It. FortiK/fio/i of Woo(/)i. Hornbeam can be sown, planted, or naturally regenerated ; the latter is a suitable method. Sowings and plantings do not require shelter. The seed ripens in October, and falls from that time until towards spring ; it keeps its germinating power for two or three years ; up to 80 per cent, are capable of germinating ; it is good seed if 65 per cent, germinate. One pound contains on an average about 15,000 clean seeds without wings. 818 NOTES ON BRITISH FOREST TREES. The seed germinates only in the second spring, that is to say about eighteen months after ripening. The best treat- ment consists in bedding it mixed with sand in a ditch, stirring it from time to time, and sowing it in the spring of the second year. About 35 pounds of seed per acre are required for broadcast sowings ; it requires a covering of about ^ to f of an inch. In nurseries the seed should be sown in drills ; the seedlings may be pricked out when one year old. Plantings are done with plants three years old and upwards, the plants being put about 4 feet apart. They stand pruning well. The tree can also be propagated by cuttings, Avhich may l)e several feet long ; the latter method may ])e employed for hedges. In regenerating hornbeam naturally by seed, the seeding cutting is mucli heavier than for beech, while the remaining shelter-wood may be removed much more rapidly, owing to the hardy nature of the tree. /'. Teiidhitj. Hornljeam is well adapted to maintain the fertility of the soil, but not to the same extent as beech. It is little threatened by external dangers ; the tree is frost hardy, but during youth liable to suffer from continued drought. Inun- dations affect it little. Game and cattle browse the leaves, and mice peel the bark, which is also sometimes done by red deer. The damage heals, however, quickly. The hornbeam rarely suffers from insect attacks. The species infesting it are much the same as those of the beech. In addition, the larva) of the Winter moth, Chcimatohia l)nim(it((, strip the hornbeam of its young leaves. Fiouji : — KxoascHs rarj)iiii produces witch's broom ; canker on stems and branches is produced either by Xectria (Utissiina, or by frost. On the whole, hornbeam woods re(iuire little tending. The tree stands any amount of pruning. The thinnings are done on lines similar to those referring to beech durhig the first THE OAK. 319 half of life ; afterwards hornbeam thins out naturally more rapidly than beech. 3. Oak — Qiierciis (Tournef.). The two species of oak which will be dealt with are the English or pedunculate oak = Quercus jjedunculata, Ehrb., and the sessile-flowered o&k = Que>-cus sessilijiora, Salisb. From a sylvicultural point of view they are so much alike that they may be taken together, any differences being specially noted. a. Utility. Oak timber is the most valuable of the indigenous species ; it is heavy, hard, very durable, and splits well ; it makes a good fuel. It is used for many purposes, in shipbuilding, housebuilding, implements, machinery, manufacture of casks (as split wood), railway sleepers, in fact for any purpose where a strong durable timber is required. The bark yields an excellent tanning material. The acorns are good fodder for pigs and deer, and are also used for tanning and dyeing. Specific gravity of air dried wood : Pedunculate oak = '76, sessile-flowered oak ■= '1^. b. Distribi'fioit. Pedunculate Oak. — All over Europe up to the 60th degree of latitude, in North Africa, and eastwards to Syria. It is a tree of the low lands, but goes up to 1,500 feet elevation in England, to 3,000 feet in the Alps, and to 4,500 feet in Greece. It is indigenous in England, Ireland, and in Scotland up to Sutherland; it ascends to 1,350 feet in the Highlands. Sessile Oak. — Does not go beyond the 54th degree of latitude, but rises higher in the hills, up to 4,000 feet in the Alps, and to more than 6,000 feet on Mount Etna. Somewhat more a tree of the low hills than the pedunculate oak, but becomes a tree of the low lands in the northern part of Europe. 820 NOTES ON ninrisH forest trees. The pt'dunculate oak is much more fi-equent in Britain than tlie sessile oak, ])ut the latter is common in Wales. r. LoidJih/. Cliiiutfc. — Oak requires warm air; it suffers from late frosts, l)ut not so much as beech, as it sprouts later in sprin^,' ; it also suffers from severe winter frosts. It is a light demanding species, which should have its head free to the full enjoyment of light. It does not require much moisture in the air. It is more storm-lirm than any other indigenous species. The sessile oak requires somewhat less warmth in the air than the pedunculate species ; hence it goes higher in mountains. .S'f)/7. — Oak requires a soil which is deep, at least fresh, warm, and fertile ; it accommodates itself to moist soil, and is not very sensitive as regards inundations. Fertile loamy soils cause its highest development, but it is also found on cla , and on sandy soil if it is sufficiently moist. On the whole it is one of the most exacting indigenous species. It thrives better on southern than on northern aspects. The sessile oak is somewhat less exacting as regards fertility, and requires a little less moisture in the soil ; hence it is found in poorer and drier soils than the pedunculate oak. If grown as coppice, the oak is less exacting than if grown as a tinibei- tree. f nirtisi'lhi. The bark is sought and badly gnawed by the hornet. The Coss'nhf readily attack it, ZcKzera preferring the saplings to any other food plant. The bark-beetles, ILih'ainHs fraxini and cnniatiis, kill sickly trees ; the former also attacks the upper branches of healthy trees and kills them in a few years. Cankerous spots in the bark may ])e caused by Xictria (Utissima. The thinnings of ash woods should be such as to enable the tree to lay on diameter increment, in other words to give it a liberal growing space at all times, and especially with advancing age, i). Elm — Ulmus (L.). The following two species will here be noticed : — (1.) The common elm= Ulmus campestna, Sm. (2.) The Scotch, wych or mountain e\vQ.= UhnH>i nioitUina, Sm. a. Vlilili/. Elm yields a coarse timber which is hard, moderately heavy, difficult to split, very durable, even when exposed to become alternately wet and dry. Specific gravity of air dried common elm', mean = '73, of mountain elm = -(il). It is used for a great variety of purposes in rural districts, by the carpenter, joiner, wheelwriglit, turner, boat-builder, and others. It yields a fair firewood, and the leaves are good foddei-. The ashes yield excellent potash. h. hislrlbiilion. Common Kim. — Central and South I'hirope, North Africa and Siberia ; goes up to 4,000 feet in the Alps. It is found in England up to an elevation of l,r)00 feet in Derbyshire, THE ELM. 329 also in Ireland, rarer in Scotland. Introduced into Britain, where it does not, as a rule, bear fertile seed. Wych Elm. — Europe and Siberia. Indigenous in Britain, going north to Sutherland, also in Ireland. Ascends to 1,300 feet in Yorkshire. r. LomlUij. Climate. — Elm requires a mild climate, but is not sensitive to late frost. It is a light demanding tree, but less so than oak and ash. It is only fairly storm firm, and the branches of old trees are easily broken. Soil. — Elm demands a deep, fairl}' porous, moist and fertile soil to do well ; hence it is mostly found on alluvial soils in low lands and valleys. The wych elm is somewhat less exacting than the common elm. (]. Shnpr anil IkTelopinenf. The elm divides into branches at about half its height. The crown of the common elm is narrow and tends upwards ; the wych elm has a broader crown. The root system consists of a tap-root with numerous side roots ; at an advanced age the system becomes somewhat more shallow. It grows quicker than oak, but rather slower than ash, and reaches an ultimate height of about 110 feet ; the common elm under specially favourable conditions up to 125 feet. It attains a consider- able diameter.* It is a long lived tree, reaching an age of 500 or even more years. ('. Reprodurtive Power. The elm commences producing seed plentifully at the age of about 40 years. The crops are heavy and occur about every 2 or 3 years ; in Britain the seed of the common elm very rarely ripens. On the whole the reproductive power by seed is great. Both elms have a great reproductive power from the stool, there being stool shoots and suckers ; they also * The author has seen, at Schimsheim, in Ehenish Hessia. a cuniiiiou ehii tree of fourteen feet diameter measured at three feet from the ground. 330 NOTES ON HKITISH FoUKST TKE1-«S. reproduce well by stem shoots. Trees upwards of 40 years old when cut over still reproduce well from the stool. /. ( linruitcr ami Comi>osilion of Woods. VA\\\ is not well suited for pure woods. It does much better mixed with beech and hornbeam ; it is also grown with oak, ash, alder, and others, not unfrequently in coppice with standards. It holds its own against these species, except beech, which may outgrow it during the second half of life. If pure, elm should be underplanted like oak. //. Si/lririilhirdl Sijsfcms. High forest, standards in coppice, coppice, and pollards. //. Fornuilinn of Woods. The elm is generally planted ; the plants are either raised from seed, or they consist of suckers or layers. As the seed of the common elm does not ripen in Britain, it is generally propagated in the latter way in this country. The seed ripens in May to June and falls almost immedi- ately ; it keeps its germinating power only for a short time, and must be sown at once. If 80 per cent, germinate, it is considered good seed. There are about 60,000 seeds to the pound. In nurseries the seed is best sown broadcast and very slightly covered with fine earth, one-tenth of an inch being sufficient ; it germinates after 2 — 3 weeks. The seedlings may be placed in nursery lines in the following spring, and they are fit to be put out after another year, though they frequently remain longer in the nursery. The methods of obtaining layers and suckers have been shortly indicated on page 221. i. Tnidinii. The elm, being hardy and grown mixed with other species, does not recpiire nnu-li tending. Cattle and deer do damage by itrowsing, but llie damage is quickly healed. Insects and THE SWEET CHESTNUT. 331 fungi do a moderate amount of damage. The elm suffers from two scale-insects, Schizoneura lanigera and Lecaniiun vagabunchnn ; the latter lives on the stems of saplings, destroy- ing large patches of bark. Elms have been much injured by two bark-beetles, Hylcsinns vittatas in Central Europe, and Scolytus Geoffroyi {destructor, 01.). The latter is exceedingly harmful to the mihealthy elms growing near large towns ; it also attacks trees in the open country, selecting weak spots, generally the extremities of old branches, at the summit of the tree, and working down the trunk year by year. Of funyi nothing need be mentioned. Elm generally holds its own against the species with which it is usually mixed, except perhaps beech, but from middle age upwards it must be given a liberal growing space by thinning aw'ay the other species to a sufficient extent. 6. Sweet Chestnut — Castanea resca (Gsertn.). a. Uiility. The chestnut yields a fairly hard, moderately heavy timber, specific gravity air dried = '61, splits well, durable. Used for building, in carpentry, staves for wine casks, vine stakes, hop poles, pit timber, etc. It is not a very good firewood, but; the charcoal is much appreciated by blacksmiths. The bark is used for tanning. The fruit is eaten. h. /Jis/n'buf/o/i. Asia, Europe, North America. In Europe it is indigenous in the south and west ; introduced into Britain, where the fruit rarely ripens fully. It rises to 2,800 feet in the Alps. In its natural home the chestnut is a tree of the lower hills and mountains, preferring northern and eastern aspects, rarely found in the low lands. r. Locality. Climate. — Kequires a mild climate, is tender against late and eai'ly frost and also severe winter cold ; drought also does •Viz NOTKS ON liHlTISH FoHKST TUKKS. not suit it. Cliestmit is a light demanding tree, but less so than oak. During youth it stands some shade, so that it thrives under Scotch pine woods. Later on in life it becomes more light demanding. It is storm firm. Soil. — Chestnut likes a deep, porous, fresh and fertile soil. It can grow in rather dry soil if deep, but avoids wet localities. A loam}' sand suits it best ; it does not like heavy soil, and avoids calcareous soils. '/. Slmije (till I hi-rcldiuiicnl. Chestnut has a straight stem, wliicli. Ikjwi-vit, branches at a moderate height. If space permits, it produces a broad ci'own, which is fairlj^ dense. The root system is deep going, resembling that of the oak. The height growth during youth is somewhat more rapid than that of oak, but it does not reach the same height as the latter. It attains a very large diameter.* It is a long lived tree, reaching an -age of more than 500 years. r. li)'iii(iduilirr Power. Chestnut comes into full bearing at the age of about 50 years. Full seed years occur every "2 or 8 years, though some seed is produced almost annually. The reproductive power from the stool is very great ; even the stools of trees up to 100 years old, when cut over, yield shoots ; the stools last a long time. f. ('hiiracirr anil Cdiii/ivsHinn nf Wnods. The chestnut is not very suitable for growing in pure woods as high forest, as it opens out about the same time as the oak, though not to the same extent. Such woods require under- planting, it is, however, grown pure as coppice. It does well in mixture with beech and oak as high forest ; in coppice • A cliestniit tree uii Mount Klii:i is reported to have a i:irtli of about •2m feet (Dohiiur-Xoljbej. THE SWEET CHESTNUT. 388 it is grown mixed with many species, as beech, oak. ash. ehn maple, lime, birch, hazel, willow, aspen, etc. If. Sulririillural Si/steiua. High forest, standards in coppice, but chiefly coppice. In Southern Europe it is much grown as a fruit tree in open woods. As high forest it is treated under a rotation gener- ally not exceeding 100 years, as coppice under one of 5 to 80 years, according to the size of the required material. //. Formation of Woods. Direct sowing is done, but chiefly planting. The chestnuts ripen in October and fall immediately. They retain their germinating power for about six months. Of good chestnuts not less than 60 per cent, should germinate. One pound contains about 115 chestnuts. Direct sowings should be made in spring, as the chestnuts are liable to be eaten by mice if sown in autumn ; they should not be sown too early, as the young seedlings are tender against late frosts. The chestnuts should be covered with about 1^ inches of soil ; they germinate after five or six weeks. The treatment of chestnut in nurseries is similar to that described for oak (page 323). /. Tendiwi. Young chestnuts must be protected against late and early frosts, either by sheltering them artificially or by raising them in sheltered localities. They also require protection against cattle and deer, which browse them. Further on in life chestnut suffers much from frost cracks. Damage by insects and fungi is not of much importance. The only part of the sweet chestnut liable, as a rule, to damage by insects is the fruit, the crop of which may be much lessened by the internal-feeding larvfe of species of Carpocapsida among the Tortrkcs. The chestnut stands pruning well. Thinnings are made as in the case of oak. .'331 NOTES ON inaTisn torkst treks. 7. Maplk — Acer (h.). The followiiif,' two species are <];ro\vii as forest trees in Britain : — (1.) The great maple, or sycamore = Arrr Paciulo-pJatauua, L. (2.) The Norway m[iYi\e= Acrr pldtonnidcs, L. //. niJi/i/. The white or yellowisli-white timber of tlie two maples is moderately heavy (sycamore, sp. gravity, air dried = 'r)7, Norway maple = "74), hard, fairly durable under cover, but of short duration in the open. It has great heating power, but is not an agreeable fuel for domestic purposes. It is used by the joiner, for finer wheelwright's work, carving, mathematical instruments, rollers in cotton mills, and a variety of other purposes. The leaves yield good fodder. The timber of the sycamore is somewhat preferred to that of the Norway maple. h. hiHiiilnilioii. Siicaiiiiirc. — ]\riddle Europe and "Western Asia. Goes higher in mountains than the beech ; up to 5,000 feet in the Alps. I'rolxibly introduced into Britain. Xoriraj/ Maple. — Europe ; goes further north than the sycamore, up to (52° of latitude ; it does not go in mountains as high as the sj'camore ; to about 4,000 feet in the Alps. Not indigenous in Britain. r. IjintlHi/. C/n»«7<'.— The maple generally makes small demands on the temperature, but it suffers a good deal from late frosts, and also from excessive heat ; it is hardy as regards winter cold. As regards light requirement, it stands al)Out half-way between light demanders and shade bearers. Maple is a storm firm tree. The Norway maple is specially adapted for cultivation by the seaside ; it is somewhat more a tree of the plains than the sycamore ; it also suffers somewhat less from late frosts. .s:o?L— Maple requires a deep, fresh and fertile soil : Norway THE MAPLE. 335 maple can do with somewhat less fertile soil than sycamore, also with less moisture, but stands a higher degree of it than the other maple. d. Shape and Development. The stem of the maple, though straight, divides rather low down into branches ; it forms large oval crowns if grown in the open, which are of moderate density. In crowded woods the maple develops a tall, cylindrical stem, with a small crown restricted to the upper part of the stem. The root system is deep-going. Maple at first shows quick height growth, which falls off comparatively early, so that it is liable to be passed by beech, though it may ultimately reach the same height. Both maples reach a large diameter, and a great age. e. Reproductive Poiver. Sycamore produces full crops of seed after the age of 40 years, Norway maple a few years earlier ; they are not very heavy, and occur about every other year. On the whole the reproductive power by seed is good ; that from the stool is moderate, and the stools do not last long. /. Character and Composition of Woods. Though maple is fairly well adapted for pure woods, it is generally mixed with other species, especially beech, also oak, and even conifers. (/. Sylvicuttiirdl Systems. High forest, standards in coppice, and coppice. h. Formation of Woods. Maple is generally planted, though it reproduces naturally wherever it has a chance. The seed ripens in September to October ; it falls in October and into the winter months. The germinating power disappears rapidly after the following spring. Good seed should show a germinating percentage of at least 55. One pound of seed of sycamore contains about 5,000 seeds, of Norway maple somewhat more. •■}-5f ]VoO(h. Pure woods of alder are found in moist or wet localities, where a sheltering of the ground is either not essential or even undesirable. It is also found in mixture with other species, especially with asli, birch, elm, or oak, generally occupying tlie moister parts of the woods. //. Sijirinillunil Syslcms. Alder is mostly treated as coppice, either by itself or as underwood under standards. It is also found in high forest ; in that case rarely pure but generally in mixture with other species. As coppice it is treated under a rotation up to 40 years ; in high forest under one of 50 to 80 years. Coppice slioots reach about the same height as seedling trees. //. FarindlUni nf Wuoda. Alder woods are generally formed by planting, and then either coppiced, or, if treated as high forest, replanted. The plants are sometimes raised from cuttings and layers, but generally from seed. The seed ripens in October, and falls from November until spring. It maintains its germinating power for about one year ; if 80 per cent, germinate, it is considered good seed, but frequently a much smaller percentage is lit to germinate. One pound contains about 800,000 seeds. For direct sowings about 15 })ouiids of seed would be required i)e)" acre, but su(di sowings are rarely made, ; the THE COMMON ALDER. 339 seeds should receive a light covering of not more than one- third of an inch, and they germinate, if sown in spring, after 4 to 6 weeks. In nurseries a moist part should be chosen for the seed beds ; at any rate they must be kept moist after sowing. The seed is sown broadcast. When one year old, the seedlings may be pricked out, and left one or two years in the nursery lines. The planting is mostly done in pits. /. Tending. Alder does not require much tending. When quite young it is liable to suffer from frost lifting, owing to the moist con- dition of the soil where it is usually grown. This can be prevented by covering the space between the plants ; any plants actually lifted must be promptly put back into the ground. Considerable danger may threaten alder from the drying up of the subsoil owing to a change in the level of the ground water. Such danger must, as far as practicable, be avoided, by preventing the water from being drained away. At the same time inundation may do much damage, especially if it occurs after a wood has been coppiced, and if the water covers the stools, or if sheets of ice form over young plantations. Insects and fungi do little damage. The foliage of alder may be injured by Tortrix larv?e, or by the plant-beetles, Agelasticd-aliii and Lina cenea, both uncommon in England. The bark of young alders is attacked by a weevil, Cryptor- rJiynduis lapathi, which breeds in their stems. Older trees are bored by the Cossidce and one or two Sesias. Of fungi Nectria ditissima may cause cankerous formations, and Pnhipnrus sulphureus red rot in the stem. Exuascus borealis causes witch's broom, and several other species of this genus are found on the leaves and flowers. z2 ;J4II NOTES ON BRITISH FOREST TREES. 9. Birch— 7>'< ////'* aJIxi (L.). (f. run III. The timber is fairly lieavv, specilic gravity of air dried ^vood = •()8, moderately hard, does not split well, of small dural)ility ; good firewood, is also converted into charcoal for the manufiicture of gunpowder. The timber is used by joiners, wheelwrights, for coarse ciirvings ; in Britain exten- sively used for bobbins, also for herring barrels. The branches, and still more young shoots and trees, are used for withes, brooms, etc. The bark is used for tanning and the manufac- ture of small vessels and boxes. b. I)ishihi(li(in. It is chiefly found in Northern and Eastern Europe ; also in Northern Asia and in North America (a variety). In Europe between 47'^ and 70 latitude. It is indigenous in Great Britain and Ireland. It is a tree of the low lands, lower hills, and even mountains. It grows up to 2,500 feet in Scotland, in the Alps to over 5,000 feet. r. LoaiUtji. CliiiKite. — It requires but a low temperature, is frost hardy, and not particular as regards heat. It is highly light de- manding, almost as much as larch. It likes moist air. To some extent thrown by storms. Sutlers somewhat from snow and rime. It prefers south or west aspects. Suil. — Birch requires only a shallow soil, with a moderate amount of moisture ; it is not exacting as regards mineral comi)osition. Although loamy sand suits it best, it* accommo- dates itself to all sorts of other soils. It is found on soils ranging from poor, dry sandy soil to swampy ground, but avoids stiff clay and calcareous soils. '/. S//i>/i'- fiinl llcrfliiinHiiil, The hteiu is generally wavy or undulating, and divided into branches in the upper part. The trown assumes an elli})tic THE BIRCH. 341 shape, and is thin. The branches are often drooping. The root system is weak and shallow. It grows quickly from the l)eginning, l)ut rarely reaches a height of 100 feet, generally not l)eyond 70 or 80 feet. Its volume growth is smaller than that of most other important forest trees. Its life seldom exceeds 100 years. p. Rcjiroductivc Poiirr. Birch begins producing full crops of seed when about 25 years old ; they recur every two or three years and sometimes annually, and are heavy. On the whole, the reproductive power by seed is very great. The light seed is easily carried about, and young birch springs up wherever there is room for it, owing to the accommodating power of the species. The reproductive power from the stool is weak ; the shoots spring chiefly from the root neck ; the stools are Hal)le to die after two or three rotations. f. (Jhararler and ('onijjosiiiu/t of Woodn. Owing to its thin crown and great light requirement birch is not well suited for pure woods ; nevertheless it appears pure over extensive tracts in Northern Europe (Eussia, Scandinavia, and Britain), owing to its great reproductive power and accommodating character, which enables it to grow in localities where other species would not thrive, or where it outstrips them. In such localities its preservation is justified. In other localities it should be mixed with species with dense crowns, such as beech. It is not so well suited for mixture with conifers, as it injures them Ijy the whip-like action of its slender branches. //. Si/h'indlvral Systems. High forest, also standards in coppice ; little suited for coppice. Excellent shelter wood over a tender species ; planted in shelter belts and wind breaks. Useful for filling 342 NOTES ON BRITISH FOREST TREES. l)laiiks in existing woods. It is treated under a rotation of 10 to ()0 3'ears in high forest, and of 15 to 20 years as coppice ; for the production of withes it may be cut over after 3 to a years, according to circumstances. Ii. Formation of 'Wtmls. They can be formed artificially or naturally. The seed ripens from the end of August to October, according to locality, and commences falling soon afterwards up to February. It maintains its germinating power for (5 to 12 montiis. It is considered good seed if 20 per cent, of it germinate. One pound of clean seed contains something like 800,000 seeds. Direct sowing is rarely done. Broadcast sowings would require about 30 pounds of seed per acre, which should be very thinly covered, only about one-eighth of an inch. The seed germinates after 2 to 3 weeks. Seed which has ripened early in the autumn may germinate in the same year : other- wise it lies dormant till spring. In nurseries the seed is sown broadcast and covered by sprinkling a little earth over it. The one year old seedlings may be pricked out and left for one or two years in the nursery lines, according to requirements. On the Continent one or two year old plants are used for planting. Birch can easily be regenerated naturally under a very small number of mother trees. Generally it appears wherever it has a chance of springing up, and the forester has more to fight against it than to favour it. /. Tr)iillii;l. Fcrtilit/i of .S'o/7.— Eaily opening out and a thin crown do not enable the birch to act beneficially upon the soil ; hence it should not be grown pure, except on localities where more valuable trees will not thrive. KxtcDud Danfji'i-H. — Birch, being very hardy, requires no tending against climatic infiuences : the damage done by snow, THE WILLOW. 348 rime, and storms is moderate. It is less nibbled by cattle and deer than almost any other broad leaved tree. It is attacked by mistletoe. Insects. — The leaves support a very large number of larvse, which, as a rule, are not gregarious. Injury is occasionally caused by the following species : — Lipar'is dispar, and monacha ; Eriogaster lanestris, Pi/;i(era hucephala. llhiinchites betuhe and its allies cut and roll up the leaves. The young stems are injured or killed by the larvae of species of Agrilas and Sesia, and by Zeuzera ascidi. The goat-moth, Cossus, lives in older trees, which are also liable in some localities in X. Europe to suffer from the burrows of a bark-beetle, Sculi/tas Ratzehurgi. Birch has no serious enemies amongst fungi. Exoascus targidus produces witch's broom ; Poli/punts bctidiuns, red rot ; P(dijponts hcvigatas, white rot. Birch is rarely pruned. Thinnings are regulated naturally, as the weaker individuals are speedily suppressed by a moderate number of dominant trees per acre. In mixed woods the more valuable species require, during youth, to be protected against the birch, as the latter generally grows quicker. 10. Willow — Scdix (Tournef.). Of the numerous species of Willow only the following four need be mentioned here : — (a.) Common sallow, or goat willow = .S'a/y',i- caprea, L. (/>,) White willow = Salix olba, L. {<■.) Crack willow, or withy = Scdix frag ills, L. (d.) Common osier = Salix viminalis, L. The willows yield a soft light timber which is little prized, except for some special purposes, as for cricket bats ; their principal value consists in yielding withes and materials for basket work, cask hoops, etc. The wood is not good fuel, but may l)e converted into charcoal for the manufacture of gun- powder. The bark is used for tanning. The osier yields the •*{ll NOTES ON BTITTISH FOHKST THKKS. liirgest quantity of material for basket work, Imt xarioiis other species are grown for the same purpose. '/. Common Sallow. The sallow occurs all over Europe, North and West Asia, Himalayas, It is found in Great Britain up to Inverness, and in Ireland. It ascends to 2,000 feet in the Highlands and to about 5,000 feet in the Alps. It is a tree of the low lands and outer hills, prefers a fresh soil, but can do even with dry soil ; appears on calcareous soils. The tree is little exacting in respect of climate and hardy. It is light demanding, of quick growth, and has a thin crown which cannot do justice to the soil. It is treated as coppice wood, under a rotation of 10 to 15 years, having a good reproductive power from the stool; yields firewood, withes and fascine wood. It appears plentifully in high forest, but is generally removed in the cleanings and early thinnings. The seed of this willow ripens in May or June, and must be sown at once, as it does not preserve its germinating power. Sowings of willow are, however, never made in sylviculture. The tree is propagated b}' cuttings. These are cut, from a foot in length and upwards, from the previous year's wood, though older wood may also be used. The cuttings may be placed into a nursery for one year, or planted out at once. Unless the soil is very loose, holes should be made, into which the cuttings are planted. The area should be kept clear of weeds, and the surface soil loosened between the cuttings. It is nibbled by cattle and deer, and peeled by mice. h. Whilr Willoir. Europe, North Africa, North and AVest Asia, North-West India. It is planted in all parts of Great Britain and Ireland, generally along the banks of rivers. It likes fresh, loose soil, especially of a loamy nature, but is not very exacting ; is light demanding, grows rai)idly, has a thin crown, and is hardy. THE WILLOW. '6i.b The white willow is hest adapted for pollarding (topping), less suited for coppice. It also appears in high forest amongst other species. As pollards, it is worked under a rotation of three to six years ; the material is used for fascines, cask hoops and basket work. It is propagated by cuttings, which may be five and six feet long, so as to produce a tree in the shortest possible time. As regards animals, see common sallow. r. ('rark Willoir. Europe, North and West Asia. Planted along river banks and low land generally ; likes moist or wet soil, especiall^^ loamy sands ; light demanding, thin foliage ; grows rapidly ; hardy, but suffers from snow and rime ; good power of reproduction by shoots. It is suited for pollarding and coppice, and is treated like the white willow ; the shoots are not suited for basket work, as they are liable to crack. (I. Common Osier. Eussia, North Asia ; cultivated throughout Europe. It is extensively grown in osier beds, which are generally established along river banks and other low lying parts of the country, on loose, moist, sandy soil ; it is, however, exacting as regards general fertility of the soil. It is light demanding, with a thin crown ; grows rapidly ; fairly hardy, but suffers sometimes from frost, insects and fungi. The osier is treated as coppice. The rotation depends on the desired material, and ranges from one to six and even eight years. Material for fine basket work is obtained by cutting annually. Reproduction is powerful, but the stools do not last for more than perhaps 15 years, and fre(|uentl3' not so long. The osier is propagated by cuttings as described for the common sallow. In England the cuttings consist frequently 846 NOTES OX BRITISH FOREST TREES. of whole shoots, of which only about one foot of the lower end is inserted into the s^'onnd ; the}' are planted immediately iiflei- (•uttin<^'. Ill Sir Is 1)1/11 n'ai/fi lu Williiirs i/niny/lh/. Willows generally are injured l)y numerous insects, which are common to most species. The wood, chiefly of Salir allxt, is much attacked by Aromia moschata, Lamia tc.rtor, and other Longicorn beetles, and by the ,c;oat-moth, Cossiis. The leaves are attacked by various liombi/ces, as lAparis saliris and Piliict'])liaht ; by sawfly larv?e, and by plant-beetles, esi)ecially the species of PIn-afora and Galcnica. These are very injurious to Salix riiitiii(ili>!, as are the leaf binding larvae of Earias rliJomna. The twigs are injured by Sesi'uhc and by gall-gnats (Cccidoiin/'uhf). A weevil, Cri/ptorrJii/iicJiiis lapatJii, destroys the bark and shoots, especially of S. riiuinalis. Of finifii, several species of Melampaora produce a rust which causes the leaves to die. Poli/ponis xiilpJnircns \n-o- duces red rot in the wood. 11. Vovh\R—P()})i(h(^ (Tournef.). The following three species must be mentioned : — («.) Aspen = PopiiJiis tremida, L. {!).) White poplar, or abele = Popnlits alha, h. (c.) Black poplar = Popidiis )ii;ira, L. f/. Aspeji. i. Utimty. The aspen yields a soft light timber, of small durability in the open ; average specific gravity = '51 ; heating power small. It is used sometimes under cover for buildings, for packing and cigar cases, rough cooperage, inner work of carriages, manufacture of matches, and of paper. The charcoal is used in the manufacture of gunpowder. The bark is used in taiining and dyeing (for the latter purpose also the leaves). THE POPLAR. 847 ii. DrsTKiBrnoN. Europe, North Africa, North Asia. Indigenous in Great Britain and Ireland. Ascends to 1,600 feet in Yorkshire ; to 4,000 feet in the Tyrol. Found over extensive areas in North- East Europe. iii. LdCALiTV. Climate. — Hardy against frost and drought. Highly light demanding, likes moist air, subject to be thrown by storms. Soil. — Grows almost anywhere, except on very poor dry sand ; moist loamy sand, rich in humus, suits it best. It is generally very accommodating. iv. Shape and Devkloi'Mknt. It develops a tall stem with a thin crown, reaching a maximum height of about 110 feet. It is of quick growth and short lived, rarely reaching an age of more than 100 j-ears. V. ReI'KODUCTIVE Poweu. Great by seed ; sends out numerous root suckers. vi. C'HAllACTEK ANU COMPOSITION OF WoODS, SyLVICULTUIIAL SYSTEMS. Earely pure. Usually appears in high forest in mixture with other species, also occasionally as standards in coppice. Generally cut out in thinnings, as it becomes ripe in about 50 to 60 years, or threatens to injure the more valuable species. vii. Formation of Woods, Dangeks, Tending. Aspen is generally propagated by root suckers, sometimes by layers ; cuttings strike less well. It springs up readily from seed in open spaces, and in young woods of other species. The young trees are nibbled by deer, also peeled. Subject to much injury by insects. Eequires no special tending. Ik White Poplar. Europe, North Africa, North and West Asia, N. W. Himalayas. Indigenous in Great Britain and Ireland. '3J-S NOTES ON lililTISH I'OKKST THKKS. Timber li^'ht. soft, spei-itic .t^ravity = -45 ; used for similar purposes as tliat of aspen, hut more valued. Found in low lands and river vallej's, likes deei), loose, moist soil, more exacting than aspen. Growtli quick, some- times reaching a height of 100 feet and a diameter of 1 foot in 40 — 50 years ; stem straight ; is light demanding ; foliage somewhat denser than that of aspen. Eeproductive power good, especially root suckers. Best propagated by root suckers, less well by cuttings. Treated as pollards, less suited for coppice. Occasionally standards in coppice. r. Hhirk Poplar. Europe, North Asia ; not indigenous in Britain, but planted. Timl)er light, soft ; specific gravity = "45 ; most valued next to tlial of wliite poplar, and used for similar pur^joses. Appears in low lands and river valleys. Thrives on any soil, if loose and moist ; does not like heav}^ soils. Grows rapidly, developing a straight stem, light demanding, hardy. Eeproductive power good by stool shoots and root suckers. Best propagated by cuttings of various length. Treated as pollards, sometimes standards in coppice. IiiticctH iiijiiriotis to poplars (lowralhj : — The leaves of young poplars of all species are much devoured by larvic, which are not gregarious, except those of Dicraiiiira and Lij)((ris .s7///r/.s-. The plant-beetles, Linn jkijuiH and trciinihc (an aspen feeder), also attack them. A Longicorn beetle, Saperda popnlneci, breeds in the twigs of young aspens, causing gall-like swellings and crippling the growth of the plant. Its congener, Sapcrda (■(irrluirhia. breeds in the stems, chiefly of black poplar, from f) to 20 years old, and is a great hindrance in many places to growing the tree. \'arious clear- wing moths, especiall,y Sesla apij'ormiii, and the goat-moth, Cossii.s, feed in the wood, often in company with Sapcrda. Oi/iniiii, Mrlainpsora species produce a rust on the leaves. The mistletoe is fre(jueiitly f(jund on poplars. THE LIME-TREE. 84-9 12. Lime-Tree or Linden — Tilia (L.). Two species of lime-tree have to be mentioned : — (1.) Small leaved lime-tree = Tilui parrifolia, Ehrh. (2.) Broad leaved lime-tree = 7't//a r/raiulifolin, Ehrh. The former is the more important forest tree. An inter- mediate species is Tilia intcnnedia, D.C.,or Tilia europcea, L., in Britain called the common lime-tree. a. Utility. The wood of the lime-tree is very light and soft, little durable, and of small heating power. Specific gravity about •45. The timber is not fit for building purposes, but is used for tool handles, by joiners and coach-builders, for carving, piano sounding boards, cigar boxes, and for paper manufacture ; young shoots are used for withes. The charcoal is used as crayons and for the manufacture of gunpowder. The bark yields bast for ropes, mats, packing, etc. The flowers yield a medicinal tea. The timber of the small leaved species is somewhat denser than that of the broad leaved lime-tree. Ii. iJisfrilnitii)//. The small leaved species occurs in Europe from the 62"^ of latitude southwards. North and West Asia ; goes up to 3,300 feet in the Tyrol. The broad leaved species is indigenous in Middle Europe and West Asia; goes up to 2,800 feet in the Tyrol. Neither species is indigenous in Britain. r. Locatitij. Climate.— The lime-tree is frost tender, and still more sensitive against drought. It is by some considered a light demander, by others a shade bearer ; practically it occupies a middle position in this respect. It is fairly storm firm. 35U NOTES ON BUITISH FOREST TREES. Sail. — A deep, thoroughly fresh if not moist, fertile soil. The small leaved lime-tree is somewhat less exacting as regards hoth climate and soil. //. S/t(t/ii' 1 1 IK I hrrcloiniiint. When grown in the open, the lime-tree forms a fairlv tall tree with side branches coming low down the stem. In crowded woods it develops a tall cylindrical stem, with the crown reduced to its upper part. The root system is deep going. It is of quick height growth during youth, subse- quently similar to beech, reachmg about the same height. It attains a large diameter and a very great age. c. Ii('iiru(luilii'i' I'dirir. The lime-tree commences producing full crops of seed after the age of 30 years, and they occur about every other year, showing a fair reproduction by seed. Reproduction from the stool is excellent, and the stools last a long time. f. ('Ii(iii(rlcr ami Cuinpiislllun nf Wands. The lime-tree is, owing to its dense foliage, well suited for pure woods, but, as the timber is of inferior (juality, it is not so grown, except in some parts of Xorth-Eastern Europe (the small leaved species). As a rule it is found mixed with other broad leaved trees. J. SijIrkuUuial Suslvnis. High forest, and coppice either simple or under standards of other species. It makes a good soil protection wood, and is also pollarded. //. F(iniiii(iroLlvclive Power. It bears full crops almost every yeai-, commencing at an age of about 10 years. The reproductive power from the stool is good, and the latter last long. The shoots start mostly below the surface. f. Character of Woods. It has a beneficial effect upon the soil. //. Sjilriridlural jSi/sle/iis. It is generally grown as coppice, as underwood under standards, soil protection wood under oak, also suitable for hedges. //. Fonnalidii of Woods. From seed, or by layers. The fruits ripen in September, and fall from October onwards ; they retain their germinating power for about six months. The nuts must be well covered with earth and protected against mice. /. Ti'ihliHil. The young plants must Ix; protected against cattle, deer and rabbits. THE SILVER FIR. 353 Hazel is not often seriously injured by insects. The cater- pillars of some BoDtljyccs and Geometrce thin the leaves occasionally. The species of Balaninus at times greatly reduce the crop of nuts. The branches show cankerous places, which may be due to Nectria ditissima. 14. Silver Fm = Abies ijectinata (D.C.). a. Ufilify. The timber is light, specific gravity of air dried wood on an average = "48 ; soft, easily worked and splits well ; lasts well in dry localities, less so if exposed to w^eather. Timber of quickly grown trees is less durable than that of slowly grown trees such as are produced in crowded woods. It is used in Britain for a variety of purposes, principally as boards, planks, rafters, and small boxes for packing strawberries. Used for the manufacture of paper. Strasburg turpentine is obtained from this tree. //. Disfrihufioii. It is found naturally in temperate Europe between the 36° and 52° of latitude. It is not indigenous in Britain ; said to have been introduced about 300 years ago (1603 according to Brown). In its natural home it is a tree of the lower mountains, ascending to 2,500 feet in Central Germany, over 4,000 feet in the Alps, and 6,000 feet in the Pyrenees. r. Locality. Climate. — Silver lir requires a fairly warm climate, and stands in this respect near the beech. It is subject to injury by late and early frosts, and is also tender as regards drought. It stands a great amount of shade, even more than beech ; in fact, more than any other forest tree mentioned in this part. It requires a certain amount of moisture in the air, but not so much as spruce. Northern and eastern aspects suit it best. It is fairlv storm firm. .•i54- NOTES ON BRITISH FOREST TREES. ,S',>//. — Silver lir requires a deep, fresh and fertile soil, rather binding than loose. Loamy soils suit it best, though it will do well on sandy soils, if fresh. Dry or acid soils do not suit it. il. Slnijir (Hill l)i'Vrloinm-iil. The silver lir develops a slrai«^ht and undivided stem, occasional forking excepted, with comparatively thin branches. The crown maintains a conical shape until the height growth has been completed, when the top becomes Hat ; in free standing trees it extends almost down to the ground, and even in crowded woods to nearly one-half the length of the stem. It has a fairly deep going root system. Silver tir is of very slow height growtli during the lirst 10 to 15 years of life, then the rate increases to such an extent that it reaches ultimately a greater height than any other British forest tree except spruce and the recently introduced Douglas tir. Woods of an average height of 120 feet are frequently seen, and single trees occasionally attain a height of 150 feet. In volume increment silver tir is probably only surpassed by the Douglas tir. Silver fir rarely reaches an age of more than 800 years. r. Rt'iiiiKhirlirr Poircr. Silver iir produces full crops of seed from the 70th year onwards. Such crops are but light, and in favourable localities they occur at intervals of two to three years. On the whole the i-eproductive power by seed is not great. Repro- duction from the stool may be said to be nW. /'. (lidraricr (did Coiiiiiusilioii nf Woods. Silver lir is excellently suited for pure woods; it has a dense foliage, and maintains a cover overhead to an advanced age, under ^Yhich a thick growth of moss springs up, thus preserving a suitable degree of nu)istur(; in the soil. It also forms a suitable stock with which other valuable timber trees, such as spruce, larch, Scotch pine, oak, etc., may be mixed. It is most frequently found mixed with spruce. THE SILVEK FIR. 355 as it has the same shape and approxnnately the same height growth. Silver fir, being deeper rooted, protects the spruce from being thrown by storms. Another most excellent mixture is silver fir and beech, as they make similar demands on the locality. Oak in mixture with silver fir does well, provided the former has a decided start to prevent being outgrown. Silver fir is a very useful species for under- planting oak, larch, and Scotch pine, when these species commence to thin out, while they afford to the young silver fir the necessary shelter against late and early frosts and drought. //. Sijlvicultnral Systems. Silver fir is only adapted for high forest, more particularly for the shelter-wood systems with natural regeneration by seed. If grown on blanks it requires nurses to protect it against frost and drought while young. It may be seen occasionally as standards in coppice, but this is not advisable, owing to its dense foliage. As it does not reproduce from the stool, it cannot be grown as coppice ; it makes, however, good hedges. Silver fir is generally worked under a rotation of 100 to 140 years. //. Fonniitioii of Woodx. Silver fir is, even more than beech, adapted for natural regeneration under a shelter- wood. Direct sowing and planting should be done under a shelter- wood ; if this is not available it must be supplied artificially, otherwise the young trees will suffer from late and early frost, and possibly also from drougbt and insects. The seed ripens in September to October, in England towards the end of the latter month. As the seed falls at once, the axis of the cone alone remaining on the tree, the cones should be gathered as soon as ripe. Tbe seed rarely keeps its germinating power for more than six or seven months. If 40 per cent, germinate it is considered good seed. A A 2 356 NOTES ON BRITISH FOREST TREES. One pound of seed contains about 10.000 clean ^^ni'mi^ with- out wings. Direct sowings may l)e made in si)ring or autmnn. tlie latter season being on the whole preferable, as the seed is diilicult to keep. If spring sowings are decided on, the seed must be kept in an airy loft and occasionally turned. Spring sowings sprout after three to five weeks. About -10 pounds of seed per acre are required for l)roadcast sowings ; it receives a cover of about two-thirds of an inch. Sowings in patches under the shelter of existing woods are more frequent than broadcast sowings. In nurseries the seed may be sown in drills, or broadcast : the seedlings should remain for two years in the seed l)ed, and two years and upwards in nursery linos. In Kngland they are rarely put out under live years old; the })lants may be placed :-3 to 4 feet apart. The young plants generally retjuire protection against frost and drought. The silver iir is best regenerated naturally under a shelter- wood, the selection and group system being perhaps even better suited to it than the compartment system. The process of regeneration is a slow one. In most mature silver fir woods groups of advance growth are found, where operations may be commenced. By removing the shelter trees standing over such advance growth, and gradually the adjoining trees, regeneration extends all round, and the groups expand until they ultimately merge into each other. In this way the regeneration period of a wood may extend over 30, 40, and even 50 years. The old trees, being gradually placed into an open position, increase rapidly in diameter, volume and value. At the same time they should be removed when the young crop demands it. /. Tc/u/in;/. FcriHitij oj Soil. — Silver lir, if treated i)roperly, is an excellent preserver of the fertility of the soil. Kxtcnial J)(ui'j(rn. — The young trees requije shelter against THE SILVER FIR. 357 frost and drought for 10 and sometimes even 20 ^-ears. This is given either by the mother trees or by an artificial shelter- wood of larch, Scotch pine or birch. This period passed, the tree is comparatively free from danger. Storm and snow may do damage, but not nearly so much as in the case of spruce. Cattle and deer nibble it, and the latter sometimes peel it, but it heals such damage easier than the other conifers. Squirrels bite off the leading shoots. Insects are, on the whole, not very destructive. Two species of Tortrix (T. iiinnuaiui and riifiniifrana) destroy the needles and shoots, especially in Central Europe. A weevil, Pissodes })ice(e, peculiar to this species, is destructive chiefl}^ to sickly trees. The wood-wasps {Sirci^ and some T<»mcld(f' bore into the wood, especially when newly felled. A scale insect is likely to attack young silver fir, whenever it is grown without shelter. Mistletoe is frequently found on silver fir, perforating the wood and reducing its value. Of Fumji, J'^cidiiim datintim, Lk., must be mentioned, which causes witches' broom and canker on the silver fir ; this evil occurs sometimes on a large scale. To meet it the diseased stems should be cut out as soon as possible. Of other fungi, Pliytophthora omnivora, Pestalozzia Hartif/ii, Agariciis mdh'tts and Tminetes radiciperda may be mentioned, but they do less damage than in the case of spruce. The silver fir stands j)r»»/??_r/ well. If silver fir is mixed with other species, it should be care- fully watched, as it is liable to be outgrown and injured owing to its slow growth during early youth. Thinnings rarely need commence before the 25th or 80th year ; they should be light until the woods enter the last third of their life, when they should be heavy, so as to cause the remaining trees to increase rapidly in diameter. Throughout the thinnings, and especially the early ones, all trees infected with canker should be removed, even if by so doing the leaf canopy should be temporarily interrupted ; in many cases it •"55 S NOTES ox r.lUTTSII FOREST TREES. in;iy hv possil)l(' to romovc (lie witches' l)rooin Ijefnrc llie stem lias l)ecoinp infected. 15. Common ok Norway Spruck = Picca cxcclm (Link.). o. llillln. Tlie timber of the spruce is light, with an average specific gravity of '45 ; soft and splits well : somewhat more durable than that of silver fir. It is known in fjritain as white ]^)altic pine, the principal tree of the European timber trade, and used for a great variety of purposes, chiefly in the shape of boards, planks, and scantlings. The timber grown in Britain is frequently of inferior quality, owing to its rapid growth in insufficiently stocked woods. It yields a fair fuel, and is used for the manufacture of paper. The bark is used for tanning. The tree yields turpentine. //. l)isiribi M.nu' ivas.,11 |,, believe thai t liis is i.leiil ieal willi Chrrnirs Inriri^!. tlio insect l)rct'rt»//('/-.s. — Scotch pine requires no protection against frost or drought ; frost lifting may occur in early youth. It suffers, however, very much from snow and rime, and Scotch pine woods are much exposed to fires ; to protect them against the latter regular fire traces must be cleared, and a strict watch kept during dry weather over the use of fire in the woods and in their vicinity. The tree is not much sul)ject to be thrown by wind, except on a shallow soil over an impermeable stratum ; its branches and top are, however, liable to be broken. Scotch pine is nibbled by cattle and game, but rarely peeled. Eabbits do much damage by peeling the bark of young trees near the ground, and squirrels by peeling them later on in the upper part. The number of these animals should be reduced by shooting, or trapping in the case of rabbits. Scotch pine is liable to a greater variety of insect injuries than any other tree, especially when grown on poor soil. Seedlings are destroyed by wire-worms, Tipula larvae, and milhpedes, also by chafer-grubs. Young plants (2 to o years) are injured by root-feeding bark-beetles {Hijhistrs), and they are gnawed by numerous weevils, especially Hijlohius ahietis, which kills a large number. The needles are destroyed by the larvae of LijMiris nionaelia, Fidoiua, Trachea, and other moths, Lnplii/i lis pint and other sawflies ; and on the Continent by Gastropaelia pini, which frequently kills the trees, lletinia larvae cripple the terminal shoots, which are also thinned out by Hylurgus pinipevda. Many weevils, Pissodes, Magdalinus, Tomicus hidentatus, etc., live in the bark ;it)S NOTKS ON liJMTISII 1-CtKKST THKKS. and twigs. Tlie Siriciihr and Lon^Mcorn beetles live in and destroy tlie wood. Fnmji prey upon ScDtcli pine to a very considerable extent. Phi/lopliihoia o/iinironi kills very young seedlings. Young plants and trees up to an age of about 30 years lose tlieir needles after becoming yellow or brown ; the cause of this has not yet been satisfactorily explained, though in many cases a fungus (Ili/stcriiini I'iiiastri) is present, and may occasion the disease, which is termed Schiitte in German. Both Anaricioi iiiellciis and Trametes laduipcrda do much damage. Peridcr- iniuiii pini causes canker by drying up the bark and cambium all round tbe tree, and kills the part above it ; such trees are called "' foxy " in England. ^Vilite rot is produced by 'PraiiiitcH pini ; red rot b}' Poliijtonia iap(>r(tiiii>; and mollis ; a bluish-black rot b}' Ceraatoma pilijrnim. Pni)ii)ifi of green branches cannot be recommended; dry branches may be removed. Occlusion is slow. ThinniiKjH may be commenced between the ages of 15 to "20 years, according to circumstances ; they should be light and irequently repeated until middle age. If it is then decided to underplant the Scotch pine, the thinnings must become heavier ; if not, they should continue to be moderate, so as to preserve as complete a cover as practicable. At the same time, trees are constantly dying off from various causes, such as insects and fungi, or they are broken by snow and rime. Such trees must be removed as speedily as possible ; hence dry wood cuttings are more frequent in Scotch pine woods tlian in anv other. 17. Jjlack oil AusTiUAN I'lNK ^ Pitnis Luiuio (Poir.), var. anstriara. ii. nmiij. The Austrian pine yields a light soft wood, which is very rich in turpentine, and very durable. Specilic gravity, air diicd, = "5H. It is a good building timbei', and in its natural THE AUSTRIAN PINE. 369 home the tree yields more turpentine than any other European conifer. The needles are used in the manufacture of an article which comes into commerce as " forest wool." //. Disfrihvtinn. Lower Austria, Hungary, Croatia, Dalmatia and the south- eastern Alps, where it ascends to about 4,500 feet. Introduced into Britain during the last century. c. Loi'iilitfi. Climate. — The tree is frost hardy and not sensitive to drought. It demands light, but stands more shade than the Scotch pine, standing between that tree and the Weymouth pine. It prefers dry air, and is storm firm. Suffers much from snow and rime, even more than Scotch pine. Soil. — It likes a moderately deep, porous and fairly moist soil, which need not be fertile. In its natural home it is chiefly found on calcareous soils, especially over dolomite formations, but it thrives almost equally well on any other formation. Its demands on fertility and moisture are even less than those of the Scotch pine, so that it grows on shallow, dry soils, even on rocks. It is considered one of the least exacting of the European timber trees. (/. Simpe and Development. The tree develops a straight stem ; the crown is similar to that of the Scotch pine, but fuller, stronger and denser. Its height growth is somewhat slower than that of the Scotch pine, and it does not, as a rule, exceed a height of 75 feet, at any rate when grown beyond its natural home. The root system is strong, and similar to that of Scotch pine. The volume growth is smaller than that of Scotch pine. It is said to attain a great age in its natural home. e. Reprodiutive Power. The tree commences producing full crops of seed after it has passed an age of 30 years, and they occur every 2 to 3 years, s. B B 370 NOTES ON BRITISH FOREST TREES. f. Cliurorli'r and Co/iijiosilion of Wooi/s. The Austrian pine appears in extensive pure woods in its natural home, and it is better suited to be so grown than the Scotch pine, because it has a denser crown, whicli sliades the soil better, preserves a complete leaf canopy to a more advanced age, and acts beneficially on the fertility of the locality. It can be mixed with the same species as Scotch pine, but demands more protection against being outgrown and suppressed. It does not require underplanting to the same extent as Scotch pine. I/. StjJvknJtural Systems. High forest with clear cutting, but also the shelter-wood systems. It can be used as nurses over and between lender species ; makes a good wind break along the edges of woods. h. Formation of Woods. Planting is the rule, but sowing and natural regeneration under a shelter- wood, or by adjoining woods, are also practised. The seed ripens at the end of October in the second year, and falls towards and during the following spring. It retains its germinating power for 2 to 3 years. Of good seed 70 per cent, should be capable of germinating. About 24,000 clean seeds go to the pound. The treatment of the seed and seedlings in the nursery is the same as for the Scotch pine. /. Tend'nKj. This is similar to that of the Scotch pine. The Austrian pine is exposed to the same dangers as the Scotch pine, but in a less degree ; from snow and rime it suffers, however, some- what more. It has the same insect enemies as Scotch pine, but is less frequently injured. A snail {BuUmus delictus) is an especial foe to young plants, which it kills by eating the last year's needles in spring. THE CORSICAN PINE. 371 Fungi are the same as tliose found on the Scotch pine, but they do less damage. 18. CoRsicAN Pine — Piiins Laririo, var. Corsicaiia (Poir). rf. Tlilihi. Similar to that of the Austrian pine. b. Dislribution. Corsica, Sicily, Calabria, Spain, Greece, South Piussia, generally the south of Europe. Introduced into England about the year 1815. In its natural home the Corsican pine is a tree of the mountains. c. Lor/, and THE LAECH. 375 older ones by the gnawing and breeding of a weevil, Pissodes pini, as well as by a woolly aphis Cryptococcus, sp. A bark beetle, Tomicus hideiitatus, is occasionally injurious. The Weymouth pine suffers from many of the fungi which attack Scotch pine, but in a less degree. Agar'uus melleus and Trametes radiciperda, however, do more damage, as they frequently kill young trees of this species. The woods should be kept crowded so as to kill off the lower branches, hence thinnings must be light until the height growth falls off. The dry branches remain for a long time on the stem, and it is desirable to remove them. Cutting oft" green l)ranches cannot be recommended, because it causes the stems to grow unevenly. 20. Larch — Larix europcea (D.C.). a. Utilify. The timber is moderately heavy, average specific gravity, air dried, = '62, soft, splits fairly well, very durable, lasting longer than any other coniferous timber grown in Britain ; it yields good firewood. Larch is the best coniferous timber grown in Britaui, for construction above and below ground ; it is also used for ship building. Li Britain it is used for a great variety of purposes ; it is much prized for railway sleepers, mining purposes, and makes ah excellent fencewood. Its price per cubic foot is generally about double that of Scotch pine timber. The bark is used for tanning and dyeing. It yields Venetian turpentine. h. Distrihufion. The homes of the larch are the Alps, the Carpathian and Moravian mountains, and Siberia, the latter being now considered a separate species. It has been cultivated in many countries, so that it is now found all over Europe between about the 42nd and 58th degrees of latitude. Larch is a true mountain tree ; it is generally found in the Alps between ;i7t) NOTES ox BRITISH FOKP]ST TREES. 3,000 and 0,000 feet elevation, l)ut goes up to 7,000, tliat is to say to the upper limit of tree growth. It is said to have l)een introduced into Britain in 1629 (Brown). Its cultivation in Scotland was commenced about the year 17'25.. the Duke of Athol having begun planting it over extensive areas about that time. It is found in the Highlands up to about 2,000 feet elevation, though its cultivation above 1,500 feet frequently does not pay under present conditions. r. LonilUy. Climate. — Larch can do with a lower mean annual tempera- ture than any other timber tree mentioned in this part. It suffers from drought, is hardy against frost in its natural home, but liable to suffer somewhat from late frosts in low lands owing to its very early sprouting in spring. It is highly light demanding, and requires to liave its head free throughout life. The climatic conditions required by larch have been much discussed. The majority of foresters believe that it prefers a dry atmosphere, a free and airy position, and northern and eastern aspects. It is more storm firm than almost any other conifer. Soil. — Larch requires a deep, fairly porous, and moderately fresh soil ; it avoids wet as well as drj' soil. It is fairly exacting as regards the general fertility of the soil ; loamy soil containing a good proportion of potash and lime suits it best ; in its natural home it is much found on stony soils, provided they are fresh. The natural home of the larch enjoys only a short growing season, with a late and very short spring and comparatively hot clear summer. These are conditions which seem to suit it. Britain, on the other hand, shows a much longer growing season, especially a long spring, a moister atmosphere and a more cloudy summer — in other words conditions which are altogether different from those prevailing in the natural home of llie larch. It is not nstonishing, therefore, that this vahiublc THE LARCH. o77 tree, although it grows most vigorously, suiters excessively from disease in Britain, as will be indicated under /. '/. SJiape and Dcrclnimu'iil. Larch has an undivided stem, with a conical thin crown ; where the tree is exposed to wind the lower part of the stem is frequently curved. In crowded woods the branches aie restricted to the uppermost part of the stem. It develops a tap root and generally a fairly deep going root system. It is a quick height grower from the beginning and until it has reached nearly its full height, w^hich may under favourable circumstances be placed at about 120 feet. As regards volume increment it stands between the firs and the pines. Ordinarily it would not exceed an age of 300 years, though it is said in the Alps sometimes to reach double that age. <-. ReiiniiliirUi'fi Poircr. Full seed j^ears connuence at the age of about 3U years ; they are light, and may be expected every 8 to 5 j^ears. A certain quantity of seed is produced almost every .year. On the whole, the reproductive power by seed is moderate. Larch possesses a certain power of reproduction by shoots, but this is of no practical value in sylviculture. /'. (Jharacter ami Cinniinsiliun of Wnuds. Larch preserves a sufticient cover overhead only for a limited period, generally not exceeding 30 years, when it begins to thin out admitting sun and air currents, which cause the fallen needles to decompose quickly, and the previous growth of moss to make way for grass. Hence, it is not suited for pure woods except on fertile soils or under specially favour- able climatic conditions. It is far preferable to mix larch into other species with a dense foliage, such as beech, silver fir and spruce,* against which it holds its own. Id Britain it is also * If Euvthtr investigation should show that Chermes laricis and ahietis are the same insect, a mixture of siiruce and larch may ])ecome uiidesira])lc. 378 NOTES ON UKITISH FOREST TREES. mixed with oak, chestnut and Scotch pme, but these niixtuies are not good ones in themselves ; if they are nevertheless employed, the reason is to be found in the fact that these three species are more valuable as timber trees than the above mentioned shade bearing species, and because in the moist climate of Britain a departure from the rules, which guide the forester in arranging mixtures, is more permissible tlian in dry Continental countries. Whenever larch is grown pure, it should be underplanted at the age of 15 to 30 years with one of the shade bearing species mentioned above. In addition, the Douglas fir may be suggested for this purpose, because it stands sufficient shade to grow under a thin larch wood, it requires some protection during early youth, is a fast grower, and yields valuable timber. Even the Weymouth pine may do for underplanting the larch, provided the latter is strongly thinned beforehand. //. Sijlvimltvre Sijstcms. Larch is treated as high forest, as standards over coppice, and it is frequently grown as a shelter- wood over and between tender species. In high forest it may be treated under a rotation of GO years and upwards, according to the size of timber required. It is useful to fill blanks in existing woods, owing to its rapid growth. //. Formnlion of WooiU. Larch may be planted on clear cuttings ; rarely sown ; in favourable localities it can also be naturally regenerated. Care in selectioji of sites is essential, to })revent disease being brought about by unfavourable soil and climate. The seed ripens in October or November, and begins to fall in the following spring ; some of it remains in the cones until the spring of the second year, or even longer. The empty cones renuiin for several yeais on the trees. The germinating power is maintained from 2 to 1 years. If 85 per cent. THE LARCH. 379 germinate it is considered good seed. One pound of seed contains about 70,000 clean grains. Direct sowings are made in spring, about 14 pounds of seed per acre being required for broadcast sowings ; it receives a covering of about one-tbird of an incb, and it germinates after tbree or four weeks, if the seed is fresh ; okl seed germinates very irreguhirly. Direct sowings are rarely made. In nurseries the seed may be sown broadcast or in drills. British nurserymen generally sow broadcast, about one pound of seed per 100 square feet of seed-bed. The seedlings are pricked out when one year old, or not at all. Plantings are done with two-year-old seedlings, or with transplants after they have stood one or two years in the nursery lines. Older plants are rarely used. In Britain the method of planting is generally notching ; pit planting is also done. Planting must be done early in spring, or in autumn, as the larch sprouts very early. The i)lants need not be placed closer than 4 feet apart. Owing to its great light requirement the tree is not really suited for natural regeneration by seed ; but if this is attempted, the mother trees must be placed far apart, or the area clear cut in strips, allowing the seed to fall on them from adjoining woods. The method is only successful under favourable circumstances. At any rate, a second seed year should not be awaited, but all areas not stocked by the first seed year should be planted up. Owing to the great damage by Pcziza {Dasijscypha) Will- hnnmii, the larch should in future be introduced singly into other woods, especially beech woods. '/. Tendinii. FcrtiUtif of Soil. — Pure woods protect the soil sufficiently only for about 25 to 30 years ; hence they should be under- planted. External Dangers. — In its natural home larch is hardy ; it suffers little from late frosts, and also not much from drought. •380 NOTKS ON LtPilTISH I'OKEST TREES. The damage done by snow and rime is of moderate extent, and the tree is very storm firm. In Britain it is not so storm firm, especially if the soil should be saturated with water at the time of a gale ; it also suffers somewhat more from late frosts, because it sprouts much earlier. Roebuck and deer do a great deal of damage lo larch by injuring the bark, which is also peeled by rabbits. Squirrels peel the top shoots. Hence the tree should be protected against these animals by fencing and shooting. Larch is much exposed to attacks by insects and fungi, and these dangers are much greater in countries where it has been artificially introduced. The larch is especially attacked by minute moths, as Coleopliora laricclla, which hollows out the needles, and Aniyreathia hev'ujatcUa, and several Tort rices. The " larch-bug," Cliermes larUis, is very injurious. Numerous bark-beetles live in the larch in common with other conifers. Fungi. — PJu/fophthora omnicora kills the young seedlings. Peziza {Dnsyscypha) Willhommii eats away the bark and cam- bium, causing canker ; this disease has now become so prevalent in many parts of Britain that the further production of the tree has become altogether problematic. AgaricuH i}idlcu>i kills the roots ; Trametes pini destroys the wood, leaving white spots ; Polyporus salphiireus produces red rot. Pruniufj. — The larch stands [)runing well, but the operation affords an entrance for fungi, especially Peziza Willkommii ; hence it should be done very sparingly. It is much better to grow the larch so that the lower branches die oft' and fall naturally. Tliiiniinf/s must begin earl}-. They should be light until the time has come for miderplanting, when they must be heavy, leaving only healthy, vigorous, well formed trees as the overwood which are to develop into large timber trees. Of late the Japanese larch, Ltirix le))f<>Ie})is, has been much reconniiended. Up to dale lliei-e is no proof whatever that it will do better than tlie European lan-li. On the contrary, there are indications that the latter catches u}) and pass(!S the THE BOFGLAS FIE. 381 former in height at the age of about 25 or 30 years, and that it is less branchy and straighter at that age. Again, canker has ah-eady been observed on the Japanese larch, so that it is impossible to say whether it will be more resistant against disease than the European larch. 21. Douglas Fir — Pseudotsmia Douglasli (Carr). (The "Red Fir or Oregon Pine of North America.) The Douglas fir is a native of the western part of North America, where it is found between latitudes 31° and 55° and longitudes 104° and 130°.* It is considered the most valuable forest tree of North America, owing to its rapid growth, great dimensions and the excellence of its timber. The latter is said to be equal to that of larch, while trees of over 300 feet in height, with a corresponding diameter, are said to exist. The tree was introduced into Britain in 1826 (Brown), and the experience so far gained singles it out as a most promising timber tree for this country ; hence it was considered desirable to add it to the present list. The sylvicultural data at present available are not yet sufficient to give a complete set of notes on the treatment of the Douglas fir in Britain. Numerous experimental plantations have been established in this country and on the Continent, some of which are upwards of 40 years old (apart from single trees or groups of greater age), and the following remarks are based upon observations made in these, and on the informa- tion supplied by Dr. H. Mayr, in his interesting work on " The Forests of North America," 1890. t a. Locality. The Douglas fir reaches its greatest perfection on the slopes and in the moist valleys of the Cascade Mountains in Oregon * According to Professor C. S. t>argent. t Dr. Mayr, a Bavarian Forest Officer, and now Professor of Forestry at Munich, visited Nortli America twice since 1885, and spent altogether seven months in its forests. He largelv utilized Professor Sargent's investigations. 882 NOTES ON BRITISH FOREST TREES. and Washington, and in the coast districts of British Cokimbia, a[)]ji-oximately bet^Yeen the 40th and 50th degrees of hititnde. These territories have an annual rainfall of about 65 inches, with a moist atmosphere, the climate being comparativel}' mild. As regards soil, it appears that a deep, fertile, and at least fresh, sandy loam suits the tree best. Under the most favourable conditions it here attains a height of about 300 feet. It seems to avoid stiff clay and also poor, sandy soils as well as chalk soils. In the mountains of Montana, with a comparatively small rainfall of about 24 inches and a dry atmosphere, the Douglas fir reaches, if grown on the most suitable soil, a height not exceeding 150 feet, which however is also the limit in the coast districts, if the tree is grown on moderately fertile soil. On poor soil, even in the latter districts, the maximum height is frequently found to be 100 feet or even less. From these data it appears that the Douglas iir, if it is to do well, requires a moist climate and a deep, fertile, fresh or moist soil, especially light loam. It accommodates itself to a different climate and soil, but the heiglit growth falls off in due proportion. In its natural home the Douglas fir is said to be very hardy ; in Montana it is exposed to great winter cold, and is found growing without shelter. In the coast districts, with a long growing season, it is said to suffer from early frost. In Britain it has on the whole been found hardy. Two distinct varieties are now recognised, known in Britain as the Pacitic or fast growing variety, and the Colorado or slower growing variety. The former is liable to suffer from early autumn frosts in the north of England and in Scotland ; hence its cultivation can be recommended for the south and west of England and Ireland. The Colorado variety is hardier, and is, therefore, preferred for cultivation in the north. It has, however, been observed that it sprouts earlier in spring, and is, ilKu-ofore. soniowhat more exposed to damage by spring frosts. THE DOUGLAS FIR. 8S.8 To what extent the Douglas fir ma}' be considered storm firm in Europe will depend on further experience ;, in Scotland many trees only 30 years old, grown in fairly crowded plantations, have been throwai. In exposed localities the leading shoots suffer to an excessive extent. German foresters seem to consider the Douglas fir to be a moderately light demanding species. The author is more inclined to class it as a moderate shade bearer, standing near spruce, or still nearer the Himalayan deodar. h. Sliape and Developmeni. The Douglas fir develops a straight undivided stem, except that in some localities the first 6 feet from the ground are curved. Grown in the open the crown covers the whole stem and comes down almost to the ground; the stems of such trees are very tapering. If grown in crowded woods in its natural home, the lowest portion of the stem is exceptionally stout ; the crown forms a sharp cone confined to the upper half of the stem, w^iilst the bole is described as of a remarkably cylindrical shape, at least as much as that of the European silver fir. A regular wood* which the author examined in 1888 was 32 years old ; in this all the trees were excessively tapering, giving a form factor t of *39 for timber only (over 3 inches diameter at the thin end). Since then the form factor has risen to "tt-l. The growth of the Douglas fir is exceedingly fast. At the same time it varies enormously according to climate and soil. According to Mayr, a wood 80 years old and grown under the most favourable conditions showed an average height of about 133 feet, or an average annual height growth of nearly 20 inches. The Taymount plantation shows an average height growth of about 22 inches. In Montana, according to Mayr, the Douglas fir shoM'S a height growth of about 10 inches on an annual average, or * Taymount. on the estate of the Earl of Mansfield. Scotland ; area = 8 acres, t For " Form Factor" see Volume III. •SSI. NOTKS ON lUtTTTSH FOKKST TREES. about one-half of tliat in tlie coast districts. Fncler any circumstances, as far as experience goes at present, the Douglas iir, if planted in suitable localities, outgrows all European limber trees. The tree also attains a great diameter : the average diameter of mature trees, 200 feet high, in the coast districts is given as about () feet, and in Montana as about 2^ feet. It follows that the volume increment is very great. Experience up to date shows that it exceeds the fastest growing of European trees to a considerable extent, as the following data will show : — The Taymount plantation yielded the following data in 1R88:— Age = 82 years (including the age of the plants when put out). Number of trees per acre . . . = 202 Mean diameter =12 inches Mean height ..... =60 feet Volume, excluding all material under 8 inches diameter . . . = 3,738 cubic feet Mean annual production . . . =117 ,, ,, Sample areas measured in the same wood l)y Mr. Pitcaithley in 1903 showed the following results : — Age -47 years Numl)er of trees per acre . . . = 202 Mean diameter =15 inches Mean height =79 feet Volume = 10,218 cubic feet Mean annual production . . . =217 ,, ., The plantation was too heavily thinned in 1887. since when no further thinning had been made. The Taymount plantation consists of tlie Pacific variety. The Colorado variety is not likely to yield anything lil