Historic, archived document Do not assume content reflects current scientific knowledge, policies, or practices. a > ; y ; _ "y = ne + Lae 1} ( ) se > oe ar = hs ~ CarbbeanForester U. S. DEPARTMENT OF AGRICULTURE FOREST SERVICE TROPICAL FOREST RESEARCH CENTER RIO PIEDRAS, PUERTO RICO VOLUME 19 NOS. 1 AND 2 JANUARY - JUNE, 1958 Caribbean Forester El “Caribbean Forester”, revista que el Servicio Forestal del Departamento de Agri- cultura de los Estados Unidos comenz6 a pu- blicar en julio de 1938 se distribuye semes- tralmente’sin costo alguno y esta dedicada a encauzar la mejor ordenacién de los recursos forestales de la regién del Caribe. Su propo- sito es estrechar las relaciones que existen entre los cientificos interesados en Ja Ciencia Forestal y ciencias afines encarandoles con los problemas confrontados, las politicas fo- restales vigentes y el trabajo que se viene haciendo para lograr ese objetivo técnico Se solicita aportaciones de no mas de 20 pdginas mecanografiadas. Deben ser someti- - das en el lenguaje vernaculo del autor, con el titulo o posicién que este ocupa. Es impres- cindible incluir un resumen conciso del estu- dio efectuado. Los articulos deben ser dirigi- dos al Lider, Centro de Investigaciones Fo- restales Tropicales, Rio Piedras, Puerto Rico. Las opiniones expresadas por los autores de los articulos que aparecen en esta revista no coinciden necesariamente con las del Ser- vicio Forestal. Se permite la reproduccién de los articulos siempre que se indique su proce- dencia. @ | The “Caribbean Forester”, published since July 1938 by the Forest Service, U. S. Depart- ment of Agriculture, is a free semiannual journal devoted to the encouragement of im- proved management of the forest resources of the Caribbean region by keeping students of forestry and allied sciences in touch with the specific problems faced, the policies in effect, and the work being done toward this end throughout the region. Contributions of not more than 20 type- written pages in length are solicited. They should be submitted in the author’s native tongue, and should include the author’s title or position and a short summary. Papers should be sent to the Leader, Tropical Forest Research Center, Rio Piedras, Puerto Rico. Opinions expressed in this journal are not necessarily those of the Forest Service. Any article published may be reproduced provided that reference is made to the original source. Le “Caribbean Forester’, qui a été publié depuis Juliet 1938 par le Service Forestier du Département de I’Agriculture des Etats-Unis, est une revue semestriele gratuite, dediée a encourager l’aménagement rationnel des fo- réts de la region caraibe. Son but est d’entre- tenir des relations scientifiques entre ceux qui s'interéssent aux Sciences Forestiéres, ses problemés et ses méthodes les plus récentes, ainsi qu’aux travaux effectués pour réaliser cet objectif d’amelioration technique. On accept voluntiers des contribution ne dépassant pas 20 pages dactilographiées. Elles doivent étre écrites dans la langue ma- ternelle de l’auteur qui voudra bien préciser son titre ou sa position professionnelle et en les accompagnant d’un résumé de I’étude. Les articles doivent étre addressés au Leader, Tropical Forest Research Center, Rio Pie- dras, Puerto Rico. La revue laisse aux auteurs la responsibi- lité de leurs articles. La reproduction est permise si l’on présice l’origine. ek printing of this publication has been approved by the Director of the Bureau of the Budget (June 26, 8 ¢ VoL. 19 Nos. 1 AND 2 JANUARY - JUNE 1958 236100 Mines atipbean Forester C omen ts S10 MaGl ec LO The Status of Forestry and Forest Research in Puerto Rico and the Virgin Islands ___ lool The Fifth Tropical Forestry Short Course bo Or Observation of some Garibbean Forests _.... = 30 o ” 4 ‘ Ms 1 sel a ‘ . ‘ ‘ . ats : , & “; 8 i t 4 a ‘ = , ” ‘ j o , ‘ ie he i JANUARY - JUNE 1958 The Status of Foresiry and Forest Research in Puerto Rico and the Virgin Islands THE EIGHTEENTH ANNUAL REPORT GF THE TROPICAL FOREST RESEARCH CENTER 1/ Public forestry in Puerto Rico had its beginnings almost 100 years ago with the es- tablishment of a forestry department under the Spanish regime. In the long period since that time forest conservation has been en- couraged and practiced on an increasing scale recently including the Virgin Islands. Cur- rent expenditures for this purpose in Puerto Rico and the Virgin Islands are on the order of $500,000 annually, for protection and man- agement of public forest lands, assistance to private forest land owners, and forest re- search. In spite of the long history and cur- rent size of the local forestry effort, the people of these islands seem only slightly aware of their forest problems. This eighteenth annual report of the Center describes these problems and our progress toward their solution. OUR FOREST PROBLEMS The forest problems of Puerto Rico and the Virgin Islands concern our most impor- tant resources: land, water, timber, people, and money. 2./ Because of the relative size of these two islands areas this description necessarily gives most emphasis to the prob- lems of Puerto Rico. iseAy Neb The land has been the traditional basic source of income in Puerto Rico. The culture of the soil provides a substantial portion of 1/ Maintained at Rio Piedras, Puerto Rico by the Forest Servy- ice, U. S. Department of Agriculture, in cooperation with the University cf Puerto Rico. 2/ This descriptive statement is based partly upon published and unpublished data from the Division of Forests, Fisheries, and Wildlife, the Water Resources Authority and the Plan- ning Board, all of the Commonwealth Government. the food requirements of Puerto Rico, many raw materials for industrial use, and is a large source of employment. Our dense and growing population makes imperative con- tinued and increased productivity of the jand. The great variation from place to place in our climate, soils, and topography makes pos- sible the production of a large number of dif- ferent crops. This same variation limits the types of crops which can be grown in certain areas. Clean-tilled crops, many of which are high yielding, cannot be produced continuous- ly on steep slopes because of the danger of soil loss by erosion. The area of such steep slopes 1/ in the islands is estimated at 671,000 acres. Other areas cannot or should not be clean-tilled because they are rocky, wet, dry, or infertile, and because other lands, better suited for the production of these crops and adequate to supply our requirements are available. This second category of lands of limited use includes some 358,000 acres. Thus, more than 1,000,000 acres, cr nearly half of the land surface of the islands, is un- suited for clean-tilled crops. If half of our land is unsuited for clean cultivation, how are we to put it to economic use? Those crops which do not require til- ling of the soil immediately come to mind. Included are forage, coffee, and _ timber. Forage and coffee production, where possible, apparently can yield more than timber pro- duction, but they are also more demanding in their requirements. On these soils which are unsuited to clean-tilled crops, forage and 1/ All above 50% slope, nearly all above 60%. DO coffee could be marketed from an estimated 505,000 acres. The reminder, some 524,000 acres, not needed or suited for other pur- poses, can grow forests without detriment to production of other crops under a program of proper land use. Forests have grown and could again grow on all of this area, yet most of this land is virtually idle at present. WATER Water has always been and still is a limit- ing factor in the development of our other resources. In the Virgin Islands water is frequently imported for drinking purposes, and there is insufficient available water for the irrigation of fertile lands or for substan- tial industrial development. In Puerto Rico some of the urban water systems are inade- quate. Hydroelectric power production is frequently limited by a lack of water in the reservoirs. A 26,000-acre area in the Lajas Valley in southwestern Puerto Rico has to the present been low in productivity for lack of irrigation. Recently large demands for water for industrial use are heavily taxing existing aqueduct systems. They may dic- tate the location of such industries, and are a key factor in the feasibility of many of them. Our water scarcity is not generally due to a lack of rainfall. Of 13,000,000 acre-feet received each year in Puerto Rico only 1,230,000 or less than 10%, are available as constant river flow. Part of the difference is lost through evaporation, part is used by veg- etation (to advantage wherever valuable crops are grown), but about half runs off the soil surface during rains, eroding the soil and racing downstream to the sea. Even though 210,000 acre-feet are used annually in these large irrigation projects, and even though we have 19 hydroelectric power plants, there can be little doubt that we are today putting to effective use less than half of the water we receive. In the Virgin Islands the water sup- ply is less, but use there also is only a fraction of the total amount received. CARIBBEAN FORESTER Our real water problem is to conserve the water we receive until it can be effectively used. Torrential downpours provide us with rainfall more rapidly than it can be absorbed by the soil, so it runs downhill over the sur- face. This surface runoff is particularly heavy in areas where the full force of the rain directly hits bare soil, becomes muddy, and clogs the pores of the soil or where the sur- face soil has already been compacted by in- tense grazing. This surface runoff overloads our streams, overflow our reservoirs, and runs on to the sea, frequently causing flood damage en route. Such water, coming suddenly and unexpectedly in large amounts, and laden with sediment, is virtually impossible to put to use before it is lost. If it is to be stored for use at other times, such as during dry weather, huge man-made reservoirs are re- quired. Our reservoirs, expensive and im- pressive as they are, store only about 400,000 acre-feet of water each year. Moreover, they are continually losing their precious storage capacity to the sediment which, brought by surface runoff, settles in the bottom. The best way to conserve our water is to store more of it in that great natural reser- voir, the soil. Water which enters the soil, unlike that which runs off the surface to the sea, is not necessarily lost, nor does it cause erosion. While still close to the surface it is available to plant roots. At greater depths it moves slowly toward natural springs or is available for pumping from wells, in either case clear and available in dry as well as in wet weather. This is really useful water. Its storage requires nothing more than the maintenance of a porous, receptive surface layer of soil. This layer can best be main- tained by a continuous dense cover of vege- tation with a layer of leaf litter on the soil beneath it. Of all crops forest best meets these requirements. The place to conserve our water is in the uplands where the rainfall is greatest, where because of steep slopes surface runoff is most likely, and where because of elevation stored JANUARY - JUNE 1958 water can be put to the greatest variety of uses. The areas which yield the most water are nearly coincident with those areas, al- ready defined, where permanent vegetative cover is needed to protect the soil as well. Those 671,000 acres include the rainiest and steepest areas of the upland. In this area more than 600,000 acres are steeper than 45 percent slope and nearly 500,000 acres exceed 60 percert slope. The prospect of alternate sources of water, such as the sea, however economically they provide water, would in no way reduce the need for protective vegetation on these criti- cal areas to control soil erosion or to reduce flood damage caused by surface runcff, or to sustain maximum productivity from these lands. TIMBER Puerto Rico and the Virgin Islands were once covered entirely by forest. Land clear- ing for farming and timber cutting made the islands less than self sufficient in timber more than a century ago. Today not more than 5 percent of Puerto Rico and the Virgin Is- lands is covered by timber forests. Possibly an additional 10 percent is covered with low brush with almost no timber productivity. The remaining forests contain few of the tree species usually considered valuable and al- most no large trees. The trees which now are cut from these forests, because the pro- perties and value of their woods are incom- pletely understood, are generally misused and wasted. Only a very small portion of the yield of our forests is used for lumber. ‘This material must bear the economic burden of inefficient logging, poor sawing, inadequate drying, and a lack of marketing facilities. Scattered smaller trees which, if available in vs) quantity and larger sizes might be worth 60 cents per cubic foot on the stump, are dis- posed of in small iots for posts at about 4 cents per foot. If we continue to use them wastefully for round timbers, untreated with preservatives against insects and decay, they will never be worth much more than this. There can be no question that Puerto Rico and the Virgin Islands need more timber than they produce. Annual imports of primary forest prdoucts are nearly 100,000,000 board feet, plus large quantities of manufactured furniture, paper and other products. Con- sumption per capita is rising. How much timber could or should we pro- duce? The 524,000 acres of land unsuited to continuous production of other crops, should be used for timber production to the extent that it is economic. Should this area prove insufficient, forests might be grown elsewhere within the 1,000,000 acres requiring protec- tive crops or on any other land where timber growing will outyield other crops. The approximate location and productivity oi the lands unsuited for other crops are in- dicated in Fig. 1 and Table 1. The 140,000 acres shown as suited for large timber could produce high-value cabinet woods or other types of lumber. The 240,000 acres suited only for smatl timber are at present believed to be too adverse to produce trees of large size within a reasonable period of time. How- ever, these areas can produce posts, poles, or pulpwood. Some 144,000 acres are so adverse that they are not expected to produce tim- ber economically, at least in the near future. These lands need protective vegetation, how- ever, for soil and water conservation, to make possible their use for outdoor recreation areas, and to protect beneficial wildlife. CARIBBEAN FORESTER sealy Aujey Ajaajssaoxq FES} suieo] moleus BA s9|0}e] EEE saaolbuew fs sweo] Apues daaq peg8) SIIJH auoysawy] Aug [2 skejj deog iy S[IIH auojsawy] pluny Y QN3941 wadee Bp Ong mr ae Wy id a hy ii YY Lp OIld OLYANd JO SVIYV GNVT LS3uOd T “64 JANUARY - JUNE 1958 FIG. I TABLE 1 — FOREST LAND AREAS IN PUERTO RICO AND TRE ViRGIN ISLANDS LAND AREA SUITED ONLY FOR FOREST Suited for Production Probably Unsuited For FOREST LAND AREA Large Timber Small Timber Timber Production Acres PUERTO RICO ae The Coastal Plain Humid limestone hiils .... Dry limestone hills Mangroves The Moutains Steep slopes Shaliow loams Deep clays Deep sandy loams ...... Soils of low productivity Laterites Excessively rainy areas .. 54,000 41,000 25,000 THE VIRGIN ISLANDS Steep slopes Shallow loams 20,600 Acres Acres 54,000 53,000 10,000 166,000 28,090 19,000 10,000 TOTAL 140,000 The potential productivity of these 380,000 acres suited for timber crops is difficult to estimate accurately but it is believed to be not less than 15,000,000 board feet of high quality logs and 20,000,000 cubic feet of other products annually. This supply might free the islands from dependence upon importa- tion of furniture wood, piling, line poles, crossties, crates, pallets, millwork, and a num- ber of miscellaneous forest products. New spectacular cabinet woods suitable for veneers and a much-needed wooden novelty industry for both tourists and the export market might be developed. Integrated veneer production with chip-board available from smaller trees could make possible a substantial expansion of the local furniture industry. EP EVOeRA iE More tragic than the erosion, the floods, or the lack of trees are the living conditions of these people who attempt to farm the lands which should be forested. The fallacy of such land use is readily evident in their 240,000 144,000 housing, income, and diet: the poorest in the islands. The destructive nature of farm- ing these areas is evident in the need to shiit areas of cultivation from place to place each year to “rest” the soil. The people in these areas are painfully aware of the limitations of their environment. Most of them would readily accept any alternative which promised better immediate and future income. The conservation of soil and water and the production of timber in these areas will re- quire that current uses of these lands disap- pear almost completely. However, consider- ing all areas together, the present population in these areas may not greatly exceed that which might eventually be supported by a fully developed forest economy. Abandon- ment of active farming has already greatly reduced the population in most of these areas. Thus, whereas some families might have to move to adjacent lands in valleys and else- where, the problem of population adjustment might be met without large scale emigration. A problem which affects us all is the lack of naturally forested areas suited for outdoor recreation. Many attractive locations in the islands are not suitable for development as recreation areas because of deforestation. This not only limits the recreation activities of the local population but limits tourism development and income as well. MONEY The important problems arising from mis- use of forest lands and products have been described in terms of soil, water, timber, and people. Each of these problems represents an economic loss to the islands. All of us who live in this area share this economic burden which might be materially reduced. Some of this loss is intangible, difficult to evaluate in monetary terms, and thus it un- fortunately tends to escape notice. The fol- lowing examples throw light on the money values involved in these problems. These examples are all linked to improper use of lands suited cnly for forest: 1. In the Guayabal watershed sediment in the rivers coming from these lands so filled the $2,000,000 Guayabal reservoir in 34 years that another $2,000,000 had to be spent merely to raise the dam to a level that would restore the original capacity. This represents a loss of al- most $60,000, or $4.00 per acre annually for the area irrigated. The real prob- lem, sedimentation, remains unsolved, and will continue to rob the reservoir of its capacity. Soil losses from the cul- tivation of steep lands needing forest protection is the primary cause for seri- ous sedimentation damage to about 1500 acres of extremely valuable cane Jands and to highways in the lower Afasco valley in western Puerto Rico. iw) Excessive surface runoff from steep slopes causes rivers to overflow their banks, claiming several lives each year in Puerto Rico, cutting away precious alluvial soil along streambanks, subject- ing thousands of acres of the most val- CARIBBEAN FORESTER uable lands of Puerto Rico to crop losses due to flood damage, and each year causing heavy damage to roads, commu- nication lines, and towns along the lower river courses. . Water scarcity during the dry season, a natural result of the excessive surface runoff during rainy periods, has been ac- centuated materially by the removal of forest from steep lands. At present it leads to water rationing in some cities, it limits the areas suitable for new in- dustries, it is partially responsible for the expenditure of millions of dollars on large artificial storage facilities for irri- gation, hydroelectric power and domes- tic use; and in the Virgin Islands it has eliminated surface water as_ reliable source for cities. . The local scarcity of timber resulting from misuse of the forest lands and pro- products has made necessary the im- portation of nearly all lumber and many other products. The value of net im- ports of wood and wood products during fiscal year 1955-56 was $32,700,000. Of this, a value of at least $5,800,000 could have been produced locally. . The harvesting and manufacture of forest products, an industry which with- out encroaching on lands which should be dedicated to other crops, is conserv- atively estimated to have an annual po- tential gross product of $10,000,000, and employ 2,500 people, is virtually non- existent. . The cost of artificially maintaining in submarginal farming a population on lands which should be forested is com- posed of so many factors that it is vir- tually impossible to estimate. Suffice is to say that the focussing of the cur- rent level of public assistance being of- fered to these areas upon the conversion to a forest economy might make possible considerable progress toward that ob- jective. JANUARY - JUNE 1958 SOLUTIONS TO OUR FOREST PROSLEMS The forest problems just described suggest that our ultimate objectives should be that at least the 524,000 acres unsuited to other crops should be covered with protective and, where practical, productive forest. The pro- ductive forests should contain trees of the species most valuable in the market and should be managed on a basis of sustained yield, providing a continuous supply of pro- ducts and related employment, year after year. The trees should be efficiently har- vested and fully utilized for the various pro- ducts they best make. The wood should be properly dried, the products carefuliy manu- factured, and where necessary to improve their utility, they should be treated against insect attack, decay, shrinkage, and flama- bility. The population dependent upon the forest land areas should be in balance with the support which can be provided continu- ously by forestry and related work. The chief obstacles to progress these goals are the following: 1. A belief on the part of those who own or control most of the 524,000 acres that income from forestry is no greater than from farming, however destructive this may prove in the long run, or that complete lack of use, because it requires no immediate investment, is preierable to forestry. 2. A hesitation on the part of the public in general to expand public forestry in the face of the apparent difficulties in predicting the magnitude of the com- munity benefits to be derived therefrom. Both of these cbstacles presumably could be overcome if landowners could be shown that on such lands forestry pays more than other land uses and that income is not great- ly deferred. To the degree that this can be done forestry will develop “painlessly” like other attractive economic activities. To the degree that this cannot be done the public as a whole must continue to bear the burden of inadequate protection or low productivity of toward —l these lands. This burden may be gradually reduced by at least three approaches: 1. The discovery and development of new forestry practices which will be more attractive to the owners of these lands. 2. Public financial incentives for the pro- tection of and the practice of forestry on these lands. 3. Outright public acquisition, protection, management of these lands as _ public forests. Each of these approaches might be war- ranted under certain conditions, but in gen- eral they are in descending order of desira- bility. The great hope lies in forest research. Through research two-thirds of this area, some 380,000 acres, might be made perma- nently self supporting. On critical areas where this is not possible and where the land would otherwise be cultivated, financial in- centive for the protection of soil and water resources might prove desirable, or at the very least, a discontinuation of incentive pay- ments for non-conserving crops. In large blocks of such lands public acquisition will probably be the best long-run solution. PROGRESS TO DATE The Commonwealth and Federal govern- ment in Puerto Rico and the Virgin Islands Corporation have made progress toward this goal of good forestry. In Puerto Rico, some 90,000 acres have been set aside or purchased as public forest. These lands have been pro- tected, bare areas have been planted, worth- less trees have been removed, and adminis- trative facilities, roads, and recreation areas, have been constructed within them. Research on the best forestry practices has been in pro- gress for many years. In both Puerto Rico and the Virgin Islands a continuous public campaign is in progress to encourage reforestation and forest conser- vation on private lands. This campaign in- volves directly the educational activities of the Agricultural Extension Service of the University of Puerto Rico and the Virgin Is- 8 lands Experiment Station; technical assist- ance by the Puerto Rico Division of Forests, the Virgin Islands Forestry Program, the Forest Service, and the Soil Conservation Service; tax relief by the Commonwealth; free planting stock by the Puerto Rico Divi- sion of Forests, the Forest Service, and the Virgin Islands Forestry Program; incentive payments for tree planting by the Agricul- tural Stabilization and Conservation Agency of the U. S. Department of Agriculture; and research by the Forest Service. Concrete results from the forestry pro- grams are evident chiefly on the public lands. Elsewhere hardly an acre of forest is cut over with any concern for future productivity. Tree planting on private lands is at a rate which, if mature plantations are harvested promptly, will maintain tree-covered less than five percent of the lands needing reforesta- tion. The growing stock in private forests is repeatedly impoverished by frequent removal of the more valuable trees. THE PROGRAM OF THE RESEARCH CENTER The research organization now known as the Tropical Forest Research Center, one of 68 maintained by the Forest Service of the United States Department of Agriculture, has operated since 1939. Its past program has included an appraisal of a large amount of forest planting work done prior to its es- tablishment, investigation of methods for production of planting stock, the introduc- tion and selection of trees for planting under different environment conditions, studies of practices for bettering existing forests, and investigations as to the machinability of local woods. As a result there are prospects for reducing the costs of planting stock, adapted good quality tree species are known for most forest sites, and many of the tree species in local forests have been appraised as to their potential rate of productivity and their utili- ty for cabinet work. This information is valuable but with few exceptions it is not CARIBBEAN FORESTER adequate to convince the landowner that forestry is good business. The present research program of the Cen- ter is directed toward three objectives: 1. The development of economically at- tractive forest crops for the most prom- ising areas of forest lands. This in- volves coordinated testing of both the production and the utilization of such crops. to The raising of the value of existing trees and incidentally of future forest pro- duction by the development of new uses for local woods, better methods for their manufacture, and by increasing their service life through preservative treatment. 3. The discovery of economically attractive techniques for the conversion of exist- ing run-down forests into highly pro- ductive stands by favoring the best available trees. New tree crops are being tested on all of the extensive forest land problem areas. Em- phasis is upon rapid-growing, relatively short- rotation crops. New uses are being tested with the more common sawtimber species, and as many as 50 tree species may become much more valuable for fence posts as a re- sult of preservation tests in progress. The conversion of existing forest into highly productive stands, a large-scale, long-range study, is entering its third year of systematic treatment on a 7,000-acre pilot management area within the Luquillo Experimental Forest. In prospect are timber supplies adequate for small wood-using industries. In addition to its research program, the Center has entered into related activities which assist in putting to use the results of research. These include cooperative programs with the Commonwealth of Puerto Rico for the production of forest tree nursery stock for free distribution and for technical forestry assistance to farmers; demonstration of good public forest management in the Luquillo Forest and related technical advice to the JANUARY - JUNE 1958 Puerto Rico Division of Forests, Fisheries, and Wildlife; a cooperative program with the Virgin Islands Corporation for nursery stock production, technical forestry assistance, saw- milling, and preservative treatment; and the training of foreign forestry students, both in- dividually and in formal short courses for groups. The program of the Center in 1957, as in previous years, gave more emphasis to the production of forests than to their utiliza- tion. Nevertheless, the forest management research project was without a_ professional leader throughout the year, a situation which has prevailed for 30 months. For this reason only a limited amount of new research in forest management could begin. However, 137 tests already in progress were completed. This report presents research highlights which will be described move fully in subse- quent publications of the Center. FOREST MANAGEMENT RESEARCH The field of forest management research covers all aspects of the production of tim- ber. The program of the Center includes the following active projects within this field: 1. Dendrology: The identification of the trees of Puerto Rico and the Virgin Is- lands and the development of aids for their identification. 2. Seed studies: The determination of how to select, coliect, store, test and sow forest tree seed for propagation. 3. Nursery studies: The development of better techniques for the production of forest tree planting stock. 4. Planting studies: 'The development of methods for the selection of forest tree species to plant, planting, and care for forest plantations. 5. Silvics: The determination of the ef- fects of soil, climate, and plant compe- tition upon the regeneration and devel- opment of trees and forests. 6. Stand Improvement: The determina- tion of how best to improve existing forests. The research work on each of these pro- jects is oriented toward one or more of the three objectives already described. The work in dendrology is directed toward a better un- derstanding of forest trees by the public. The seed, nursery, and planting studies are concerned with the reforestation of the forest lands already described. The studies of silvics and stand improvement both concern the betterment of remaining forests on lands unsuited for other crops. Dendrology The Center moved closer to the completion oi a semi-popular book “Common Trees of Puerto Rico and Virgin Islands’’, a project of many years. The manuscript describing 250 tree species with text and plates, has been drafted by Dr. Elbert L. Little Jr., Dendrologist for the Forest Service. The draft in English was approved by a board of review during the year. Descriptions of 209 species were translated at the Center into Spanish preparatory to publication proposed by the University of Puerto Rico. Seed Studies The major tree seed problems have been studied over a period of many years. Al- though there are some serious gaps in our knowledge other problems attracted more of the attention of the Center during the year. Mexican cypress (Cupressus lusitanica) a promising tree for reforestation of steep slopes at high elevations in Puerto Rico, was subjected to a seed test. This species, exotic to the islands, bore seed in its second or third year after planting at about 3000 feet eleva- tion in the Toro Negro Division of the Carib- bean National Forest. By the sixth year a few seedilngs appeared beneath the trees. The prospect of a local seed source led to tests of seed from ten trees selected because of the natural seedling beneath them. Ger- mination, tested in the soil, was discouraging, averaging 4 per cent and with no lot reaching 10 10 per cent. Testing of the adaptability of this tree will apparently have to continue to depend upon imported seed. Nursery Studies Forest tree planting stock has been pro- duced in nurseries in Puerto Rico for more than 30 years. The Federal and Common- wealth governments now share the cost of a large-scale program of planting stock produc- tion and distribution for reforestation. Casuarina (Casuarina equisetifolia Forst.) is the most popula tree for reforestation in Puerto Rico. It is rapid growing, adapted to poor soils, and it provides stakes, posts, and poles for tobacco barn construction and maintenance. The production of planting stock of this species has always been plagued by heavy losses in the nursery; due to low germination, insect attacks and disease, and the thinning necessary to compensate for oversowing where losses were less than ex- pected. Past experience had shown that for each 330-square-foot seed bed it was necessary to sow four pounds of seed (1,200,000) to ob- tain a good stand (40,000 seedling). In an effort to reduce early mortality and to con- trol weeds a test was made in 1957 at the Catalina Nursery with soil fumigation, using methyl bromide. The result was a saving of 50 percent in seed. Weeding is the most expensive nursery operation and seriously affects the cost of planting stock. The problem recently became intolerable at the Catalina Nursery due to the spread of Jonoxalis martiana (Zucc.) Small, a persistent weed with underground thizomes. Here again soil fumigation with methyl bromide proved successful in 1957, killing even the rhizomes. The treated area remained weedless for 8 weeks, greatly re- ducing the weeding job. Planting Studies Studies of the adaptability of different tree species for planting were in progress in all of the potentially productive forest areas of the islands listed in Table 1, with the exception CARIBBEAN FORESTER of mangrove, where reforestation is not a problem. A total of 93 studies were com- pleted during the year. These showed the adaptability of a large number of native and exotic tree species. The results of these and many other previous studies are being com- piled for the preparation of a builetin on forest planting. An additional 80 studies already in pro- gress were continued through the year. Sev- en new tree adaptability tests were begun. The description of the work is here presented in accordance with the forest land areas listed in Table 1. Humid Limestone Hille This area, totalling 161,000 acres, contains more than 100,000 acres of land in northern Puerto Rico which apparently is potentially productive of timber crops. It ranges from sea level to nearly 1000 feet in elevation, with rainfall from 60 to 80 inches annualiy. The soil is acid but shallow, over porous limestone. Most of the area is forested but with trees which are of poor quality. The slow reaction of the natural vegetation to release cuttings and the inferior character of the tree species present suggest that better species must be introduced, probably by underplanting be- neath these stands. Research in this area is in progress within the Rio Abajo, Guajataca, and Cambalache Forests. Most studies are concentrated at the base of the hills on the site considered suitable for the production of large timber. The most spectacular tree species planted so far on this site is Honduras Mahogany (Swietenia macrophylla King). It is well adapted to the sinkholes between the hills and on the lower slopes. Studies completed curing the year showed it capable of high survival when planted or direct sown beneath light shade. The underplanted trees are of good form and free of insect attack. In well managed plantations the better trees average 9 inches in diameter at breast height after 18 years. However, the species has been found unsuited to the slopes above the valleys, and JANUARY - JUNE 1958 in the sinkholes serious damage was found in a few areas after the 1956 hurricane. Dominican mahogany (Swietenia mahogani Jacq) is another valuable timber species which is adapted to this area. It is general- ly slower in growth than Honduras mahog- any, but the wood is considered superior. Moreover it is adapted to the upper slope of the hills, and may be established by direct seeding on this area. One plantation under study has dominant and codominant trees with an average diameter at breast height of 6 inches after 22 years. A third species, teak (Tectona grandis L.), grows well in the sinkholes, but not on the limestone slopes. One of the world’s most useiul woods, it has attained an average dia- meter of about 8 inches in 19 years in a well managed plantation on this site. It appears to be more windfirm than Honduras mahog- any but tends to remain shorter than that species, apparently a reaction to the shallow soil. The two mahoganies and teak may well have a permanent place in forestry in the humid limestone hills. However, the produc- tion of high grade lumber, even with these species, will require at least 40 years. Al- though thinnings might repay all costs well before this date, such a long-term crop is not now attractive to most landowners. The search for short-term forest crops for this area has not yet been successful, al- though several tree species appear adapted io the lower slopes. Eucalyptus kirtoniana F. v M. and Casuarina equisetifolia Forst. both produce a large volume of polewood in a brief period here. However, neither of these species are valued highly at present because their chief local use is for fence posts. In the absence of preservative treatment posts of these species remain serviceable only about 30 months. A number of other tree species which have been under test on this site were classified as unsatisfactory during the year, either because of slow growth, poor form, or both. Among these are Cordia alliodora (R & P) Cham, Cedrela toona Roxb, Andira ja- if maicensis (W. Wright) Urban, Bucida buce- ras L and Petitia domingensis Jacq. Dry Limestone Hills The dry limestone hills of southwestern Puerto Rico contain an estimated 44,000 acres oi land unsuited for crops other than forest. As was shown in Table 1, this area is also of doubtful productivity for timber. It is mostly covered with low scrubby ‘forest growth of little value for its wood. Included within this area is the Guanica Forest. Past efforts to liberate the better trees in the natural forest from competition and to introduce better tree species have tended to bear out the belief that these lands are of little value for timber production. Ucar (Bucida buceras L), the most prominent tim- ber tree in the remaining forests, was found by repeated remeasurement to grow to slow- ly under these conditions to suggest any eco- nomic possibilities. One plantation of Do- minican mahogany on a favored site in a protected valley has produced trees of 6 in- ches in diameter in 25 years. This growth rate, although it is more rapid than that of most of the native vegetation, does not present a favorable economic picture to the owners of most of this land. Since this area is likely to be of little value as a contributor to the timber requirements of the island, in- vestigation within it is limited to routine ob- servations and periodic measurements in a few stands. The Mangroves The magrove forests of Puerto Rico border the sea along protected coasts, bays, and es- tuaries. Their total area is estimated at about 10,000 acres. Nearly the entire era is forested with two tree species, white man- grove (Laguncularia racemosa (L) Gaerth.) and black mangrove (Avicennia nitida Jacq.). Both of these appear to decline in growth rate before they reach sawtimber size and thus are best suited for roundwood products 12 such as posts, poles, or charcoalwood. Re- search in this area has been carried on in the San Juan and Aguirre Forests. Past studies have shown that the best me- thod to harvest our mangrove forest is by clear cutting. Partial cutting in 20 year- old stands, leaving the best trees to grow for the future, showed that the rates of growth olf these trees can be accelerated thereby. However, the more open forests resulting are susceptible to wind damage which can com- pletely nullify these benefits. Since most of the forests are composed of trees of nearly the same size, most of them reach maturity at about the same time and clear cutting is thus practical. Tests have shown that a new forest will start naturally within two years after clear cutting if a seed source is close at hand. During 1957 a study was completed which determined the probable quality of the stands following clear cutting. The large number of crooked trees of sprout origin common in mangrove forests suggested that stands com- ing up after clear cutting would be mostly of sprout origin and thus poorly formed. A study in a white mangrove forest showed in 1957, however, that new tree seedling also appear in the regeneration and after 5 years exceed the height of the sprouts. Present knowledge of the mangrove forest seems adequate for intensification in man- agement as soon as the products of the forest become sufficiently valuable to warrant this. One prospect is in the treatment of mangrove posts with preservatives. The work of the Center toward this end is described elsewhere in this report. The Shallows Loams of the Mountains The steep shallow loam areas in the moun- tains, where some 166,000 acres are consid- ered unsuited for crops other than small tim- ber, are critical for soil and water conserva- tion. Virtually all of this area has at one time or another been cleared for farming, and most of it is still deforested. Elevation CARIBBEAN FORESTER ranges from 500 to 2500 feet and rainfall from 50 to 90 inches annually. This area has been slighted in the past research program of the enter because of the availability of larger publicly-controlled forest areas for ¢e- search elsewhere. However, plans were drawn up during the year to begin extensive testing of new crops for this area. In preparation for full-scale testing i2 species in 6 sites within this area, prelimi- nary trials were made near Aibonito in late 1957. The species chosen were believed to be of rapid growth and merchandable as post3 and round timbers. At the close of the year survival was inconclusive. However, the di- rect use of cuttings on the field did not give more than 50 percent survival, even for such well-known sprouters as Spondias mombin L., Ficus laevigata Vahl, Erythrina poeppi- giana (Walp) P. F. Cook, and Castills elas- tica Cerb. The Deep Clays of the Mountains The steep clay areas in the mountains, be- cause of greater soil depth, are considered more suited to large timber production than the shallow loam soils. In all, some 41,000 acres are in this area, scattered throughout the mountain region, mostly between 1,000 and 2,500 feet elevation. Rainfall ranges from 80 to 130 inches annually. Part of this area is forested, notably within the Luquillo, Guavate, and Toro Negro forests and in parts of the coffee region on the western moun- tains. Nevertheless reforestation is needed on a large area subject to shifting cultivation. Past studies have shown that Honduras mahogany (Swietenia macrophylla King), is adapted to the lower elevations within this area although on wet soils it is not windfirm. This species normally is not used for refor- estation because of insect attack (Hypsiphyla grandella) Zeller), but it can be effectively underplanted beneath existing forests. Above 1,500 feet elevation reforestation has proven successful with Eucalyptus robusta J. E. Smith and F, kirtoniana F.v.M. The pros- JANUARY - JUNE 1958 pect of heavy hurricane losses with mahog- any, and the lack of a steady large market for the eucalyptus has limited their use pri- marily to public forest areas. Although a few oi the mahogany plantations, at 25 to 30 years of age, are producing lumber from thinnings, accelerated planting of this species must await more complete understanding of the capacity of the tree to withstand winds. Eucalyptus, at 12 to 20 years has become usetul for underground piling. A most impressive recent introduction on this area is Mexican cypress (Cupressus lusi- tanica Mill), a tree which elsewhere is used for Christmas trees and for lumber. This tree at elevations of 2,500 feet or more has proven capable of growth in diameter exceed- ing that of eucalyptus (more than 1 inch per year for 10 years). However, it lacks wind- firmness on certain sites. Examinations during the past year suggest that rocky soils in areas with relatively low rainfall (the shallow loam area) may prove best for this species. Other trees under observation in test plantings in this area include additional eu- calyptus, roble (Tabebuia heterophylla (DC) Britton), cedro macho (Hyeronima clusioides (Tul) Briseb.). jaguilla (Magnolia portoricen- sis Bello), and guaragua (Guarea trichilioi- des L.) Some of these are more impressive than others but none have yet been conclu- sively shown as attractive economically as mahogany or eucalyptus in this area. Roble, because of its adaptability to poor soils, has been used to reforest areas too uniavorable for other valuable tree species. The Sandy Loams of the Mountains The steeper slopes in the sandy loam areas near Utuado and Jayuya make up not less than 25,000 acres which are unsuited ‘or crops other than forest. Elevation ranges from 800 to 2500 feet and precipitation from 70 to 100 inches anually. This area is espe- cially critical for soil and water conservation. The soil is loose and erodes rapidly when 15 exposed. On the other hand, if protected, the soil is sufficiently porous to absorb and store tremendous amounts of water. Most of this area has been deforested and is sub- ject to shifting cultivation for tobacco and minor crops. The climate and soil of this area are both favorable for tree growth. Neverthe- less, here again no economically attractive tree crop has been developed. During 1957 tests began with Mexican cypress (Cupressus lusitanica Miil.). The tree survived planting but nothing is yet known regarding its rate of development and windfirmness. Future tests here are to include pines. The Laterite Soils The laterite soils derived from serpentine rock in the western mountains, found on some 28,000 acres, have mostly been farmed and then abandoned as unsuited for cropping. They range in elevation from 800 to 2500 feet, and rainfall ranges frem 80 to 110 in- ches anually. Research within this area has been carried on in the Maricao Forest. Past efforts to reforest this area with val- uable tree species have generally failed. Eu- calyptus has grown well on only a few {a- vored locations. More than 20 species of this group have been tested. Maria (Calo- phyllum brasiliense Camb) has survived well after direct seeding, but only on the more protected sites are the trees well formed. Mexican cypress (Cupressus lusitanica Mill) has recently shown promise here as 2 possible Christmas tree. Tree growth is slower here than elsewhere but the branches are firmer and more suitable as Christmas trees. In a plantation 7 years old the trees average 2 inches in diameter and 14 {eet in height. Christmas tree size was reached in A years. Kauri pine (Agathis australis) Salisb.) another tree species remeasured in this area during the year, has proven to be one of the most vigorous appearing trees tested. At 20 years of age these trees average 10 inches in diameter. 14 The most spectacular result of forest re- search in this area is the apparent success of tests with slash pine (Pinus elliotti Eugelm). Earlier tests with six species of pines on this site failed. However, inoculation of slash pine with mycorrhizae, reported previously, has continued to show promising results. By the end of the year, 30 months after inocu- lation, almost 90 percent of the treated trees were vigorous, deep green in color, and they had grown an average of 16 inches in height. None of the untreated seedlings were vigor- ous, 25 percent of them had died, and those remaining had grown only 3 inches in height. These results, while still preliminary, suggest similar tests with inoculated pines in more favorable areas. The laterite soil area is still one of the least promising, even for forestry. Neverthe- less, observations in existing forest planta- tions and the search for new, more promising tree species will continue. The Excessively Rainy Areas The upper slopes of the Luquillo Moun- tains, the Sierra de Cayey, and the highest ridges of the Cordillera Central are, because of excessive rainfall, of value only for trees. The soil in this area, highly leached heavy clays, are infertile. Even the natural forest is poor, its trees small in size and crooked. Almost all of the 19,000 acres in this area are forested. The poverty of the natural forest in this area, the high rainfall, and the unsuitability of the soil for other crops all suggest that protection is probably the highest value of the forest growth here. Attempts to intro- duce eucalyptus, cypress, and bamboo all have failed or suggest the need for special care such as the application of fertilizers. No further research is in progress here. Steep Slopes in the Virgin Islands The steeper slopes of the mountains in St. Croix, St. Thomas, and St. John are unsuited for farming. Excluding the National Park CARIBBEAN FORESTER in St. John, there are not less than 30,000 acres of land in the three islands which are suited only for forest. This area ranges in elevation from near sea level to about 1,500 feet, and rainfall ranges from 20 to 60 inches anually. Nearly the entire area is covered with woody growth which is little used. On those areas capable of producing wood pyro- ducts, the most valuable type of forest crop would appear to be attractive wocds which might provide maximum employment in the manufacture of furniture and novelty items for the tourist trade. Smaller trees might best serve for posts, poles, and charcoal for local consumption. The presence in the islands of Dominican mahogany (Swietenia mahogany Jacq.), its apparent adaptability even on some of the least favorable lands, and the quality of its wood for the purpose cited all led to the cen- tering for forestry work in the islands around this species. Honduras mahogany (Swiete- nia macrophylla King) a tree which in Puer- to Rico grows more rapidly and straighter than Dominican mahogany, is also found in St. Croix. Tests have shown it adapted to at least the more humid forest lands of that Island. Both have proven suited for under- planting in narrow cleared lines through the existing forest. With such valuable tree species already at hand and obviously adapted to at least cer- tain areas of forest lands, the first problem appeared to be the development of a cheap method to establish them. Experience in Puerto Rico had shown the necessity of keeping a ball of earth around the roots of Dominican mahogany planting stock to ob- tain high survival. Honduras mahogany, on the other hand, normally survives bare-root planting on humid sites. Tests begun in St. Croix in 1955 have shown that in favorable years satisfactory survival of both species is possible with bare-root planting if the stock is of top quality. Under these conditions even broadcasting and direct seeding can be successful. During dry years, on the other hand, Dominican mahogany stock must be JANUARY - JUNE 1958 potted, and bare-rooted stock of Honduras mahogany gives low survival except on the most humid areas. In such periods direct seeding and broadcasting generally fail since such germination as takes place precedes the dry season by only two or three months. The ideal period for planting in wet years is at the beginning of the rainy season in May, in order to provide a long growing season be- fore the first drought. However, in Gry years the rainy season may begin 5 months later leaving only 3 months in which to plant. Trees set out so shortly before the following dry season suffer heavy mortality. Because of the impossibility of predicting the weather, present practice is to plant stock rather than to direct seed, to plant all Dominican mahog- any with a ball of earth, and to confine Hon- duras mahogany to the wetter areas. In spite of the tropical value and apparent adaptability of the mahoganies in the Virgin Islands, it is desirable to use more than just these two species in forestry there. Domi- nican mahogany is not rapid growing, has an unfortunate tendency to be limby, and in Puerto Rico has recently become subject to a serious disease of undetermined origin. Honduras mahogany is generally considered to produce a less valuable wood than Domi- nican mahogany, and in some areas of Puer- to Rico it has proven susceptible to wind- throw, a serious drawback in the hurricane belt. Teak (Tectona grandis L.) was introduced into St. Croix more than a decade ago but only a few trees, used as ornamentals, have remained. It produces a wood such as needed in the islands for the purposes already de- scribed. Tests showed that it was more practical to ship in teak planting stock trom Puerto Rico than to produce it locally where small-scale production is costly and germi- nation is sporadic due to the dry climate. Test plantings show it capable of high sur- vival in St. Croix, but weeding of young plantings is a serious problem requiring at- tention at least twice during the first year. 15 A 1957 test of weel control with herbicides, using sodium TCA and CMU, was inconclu- sive because of an indicated inhibiting effect upon the growth of teak. Other species which are apparently adapt- ed to the islands and deserve consideration in future research are tibet (Albizzia leb- bek (L) Benth.) Maria (Calophvlum _bra- siliense Camb.) and roble (Tabebuia hete- rophylla (DC) Britton). The first of these is an exotic tree which has invaded pastures and roadsides. Its wood is attractive. Maria, almost entirely absent from the islands is being tested as a fence-row tree and wind- break. SL Lev ees The research of the Center in the field of silvics has in the past been concerned with the classification of different types of forest and the description of the climatic and soil conditions which produce them. The growth of trees within a large variety of forest has been measured over a period of years to de- termine its relationship to visible environ- ment factors such as light, competition, soil, and topography. Growth of Yagrumo Interest in Yagrumo hembra (Cecropia peltata L) has arisen from its use for excel- sior in Puerto Rico and from other prospec- tive uses of the wood. Since the future im- portance of yagrumo is as dependent upon supply as it is upon demand, studies of its production have begun. A first step was an analysis of existing growth records for this species. Yagrumo hembra is generally considered a very fast growing tree. This reputation is earned by its performance on areas recently cut over, where light and organic matter are plentiful and where competition with other trees is a minor factor. Growth of yagrumo in dense virgin forests, on the other hand, was reported a year ago to be nothing out- 16 standing. To provide information as to what might be expected in plantations managed at a density intermediate between these ex- tremes 8- to 10-year growth records were summarized from four plots covering 3 acres in the tabonuco type of the Luquillo Forest. This area, on deep clay soil, and receiving at least 100 inches of precipitation annually, is typical of the area where this tree occurs in CARIBBEAN FORESTER Puerto Rico. The plots measured are of mixed composition, and contain 50 trees of yagrumo. The density of these forests, ranging from 80 to 100 square feet of basal area per acre, lies near the upper edge of that which other studies have indicated should be maintained under good management. The records are summarized in Table 2. TABLE 2 GROWTH OF YAGRUMO HEMBRA ON CUTOVER STANDS Initial Number Average Average Diameter Crown Position of Trees Initial DBH Growth in Ten Years No Inches Inches Dominant 5 10.0 Bol Codominant 6 11.0 1.9 Intermediate 36 3.3 3.3 Suppressed 3 1.9 Slt These data, although they are not as strong as might be desired, suggest certain charac- teristics of yagrumo growth. Growth in all crown positions apparently can be rapid, in spite of the general belief that the tree is shade tolerant. Rapid growth can also be sustained to diameters as large as 10 inches if trees are given adequate growing space. Of these trees the most rapid growing indi- vidual, an intermediate of 3.4 inches d.b.h. at the beginning of the period, grew 6.2 in- ches in diameter in 8 years. ‘The most spec- tacular growth rate of all, that of young trees in the open such as would characterize early plantation development, is not shown in these plots. Stand Improvement Investigation of techniques for and results of the improvement of existing forests have of necessity been confined to the small areas where these remain. All work of this nature has been concentrated within the public forests. As a beginning the effects of different types and degrees of cutting upon the growth of the remaining forest were studied, chiefly on small controlled plots. These first studies showed the approximate extremes of desirable stand density and the relative response to treatment of different trees within the forest. Synthesis of the re- sults of a number of these small studies pro- vided a basic technique for stand improve- ment which has been and is being applied widely upon the public forests. Pilot Management Studv The present technique for forest improve- ment, although it appears to avoid the most serious pitfalls of mismanagement, was put to use before it had been evaluated in terms other than growth response. In order to test its practicability on a large scale and as a long-range policy it is being applied in a pilot management study on about 7,000 acres on the north slope of the Luquillo Moutains, the largest natural forest within Puerto Rico. The results of this study should, in general JANUARY - JUNE 1958 terms, be applicable to all areas of natural forest in Puerto Rico with the exception of those which prove unsuitable for timber pro- duction. Within the pilot management area an in- tensive forest management program has been undertaken. The area is divided into 46 compartments for continuous, systematic treatment on a 5-year cycle, directed toward sustained timber yield and forest employ- ment. Mature timber is sold and undesir- able trees are killed. Road construction to make all of the area accessible is contem- plated. At the end of 1957, after two years of operation more than 2,300 acres had been subjected to an improvement cutting. In anticipation of better future markets for tim- ber the least accessible areas were treated first, yet during these first two years 232,000 board feet of timber were sold for a stumpage value of about $5,000. The chief expense in forest improvement is the elimination of trees of no present or pro- spective value. Experience in 1956 showed felling to be too expensive and girdling to kill too slowly. A major improvement resulting from investigation during the year was the use of the arboricide 2, 4, 5-T (4 pounds acid equivalent per gallon) as a 45 percent solution in diesel oil. Applied in shallow frills, consisting of a continuous row of axe cuts around the tree, this solution has proven very effective, killing some trees within four weeks during the most active growing season. Nearly all trees are dead after one year. Persistent exceptions are mango (Mangifera indica L.) and pomarrosa (Eugenia jambos L). The use of poison has reduced labor costs by 75% to about one man-day per acre. The treatment itself is in accordance with the following general policy: A. Stand Condition Requiring Treatment 1. Canopy trees average 3.6” d.b.h. or more. 2. Crowns of trees mostly in contact. B. Degree of Opening Permitted 1. Trees with average of 6 feet of crown freedom on the sides. 2. No openings to the forest floor larger than 25 feet unless caused by remov- al of a single tree. C. Trees to be Removed Excess trees, as defined by B, above, in the following classes, removing first those nearest the top oi the list. 1 1. Dying, seriously diseased or insect infected. 2. Inferior species (any not included in 3, 4, or 5 below). 3. Pole species 10” + d.b.h. 4. Second class sawtimber species 16”? + d.b.h. 5. First class sawtimber species 21’? + d.b.h. 6. Remaining trees without a_ sound, straight butt section of at least 814 feet in length. 7. Remaining trees with poor vigor or seriously broken crown. 8. Remaining trees still in excess of de- sired density (Smallest and poorest first). a Pole species. b. Second class sawtimber species. c. First class sawtimber species. Detailed sampling of the results of this treatment is being made in four compart- ments representing distinct site and stand conditions. One hundred fifth-acre perma- nent plots are being established and meas- ured in each area. Preliminary data from the first of these areas were collected and summarized in 1957. This area ranges from 600 to 1200 feet above sea level. Precipita- 1/ The classification of tree species as first class, second class or poles, not shown here, is based upon past research into the characteristics of both tree and its wood. 18 tion is about 90 inches annually. Soil is a deep acid clay. The forest is secondary with no trees mature for sawtimber at present. The stand density in this compartment was reduced nearly half, from 63 to 34 square feet of basal area per acre. The volume was reduced from 430 to 308 cubic feet per acre. The composition of the forest was improved by leaving better tree species than those cut. Before the cutting 41 percent of the stand (basal area) was composed of desirable species. The cutting raised this percentage to 50. The release from competition result- ing from the cutting increased from 79 to 99 the percent of desirable trees receiving full overhead light. Remeasurement of these plots 5 years hence will show the develop- ment of the residual stand. A second im- provement cutting is scheduled for that time. THE ELIMINATION OF UNDESIRABLE TREES A study of peel-girdling of trees, the tradi- tional local method, was begun in 1952 and completed during the year. In a mixed stand on the Luquillo Forest 191 trees were com- pletely girdled by the conventional machete method, removing a broad band of bark. By the end of the first year 41 percent of the trees were dead. After 2 years 72 percent were dead; after 3 years, 82 percent; after 4 years, 84 percent, and after 5 years 89 per- cent. Sprouts developed below the girdles on many trees but usually died later with the tree, possibly because the vemaining stand was still dense and provided heavy shade. The results proved too slow for forest improvement work which contemplates rapid response to treatment prior to the next cutting 5 years hence. A second study was planned, to compare the double-hack girdle, frill-girdling, basal incision, basal spray, and bark spray with ammonium sulfamate and 2, 4, 5-T. A test of the double-hack girdle in 1957 showed an 80 percent kill in one year. CARIBBEAN FORESTER, Response of Dominican Mahogany To Release Cutting in St. Croix A windbreak of Dominican mahogany (Swietenia mahogani Jacq) planted in east central St. Croix during the Danish period has given rise to a nearly pure mahogany forest to the leeward covering an area of some 300 acres. This forest is composed of a few scattered large limby trees and a dense stand of young poles of 4 to 8 inches d.b.h. beneath them. The density of these young stands sug- gested thinning, so in 1952 two intensities of thinning were tested in the Thomas Estate Experimental Forest. The objective was to determine that level of density which would be open enough to assure rapid growth of the best trees yet sufficiently closed to prevent excessive branching of these same trees. The initial density of the forest exceeded 100 square feet of basal area per acre. One area was thinned lightly, leaving 92 square feet, and the other heavily, leaving 58 square feet. Observations during the subsequent 5 years showed that excessive branch formation was no problem in either area. At the end of the period the average annual diameter growth of the trees in an unthinned area was 0.10 inch; in the lightly thinned area, 0.13 inch; and in the heavily thinned area, 9.24 inch. The promptness and magnitude of the ‘e- sponse to the heavier thinning are not the only criteria for appraising this practice, but the results were so marked that thinning of this character is being done on a systematic basis on an 100-acre area in the Thomas Estate Experimental Forest. Growth In Cutover Colorado Type Forest The forest of the excessively rainy areas in Puerto Rico has been designated the Colora- do type because of the dominance of palo co- lorado (Cyrilla racemiflora L) m many areas within it. This forest type, composed chiefly of malformed trees, appeared at one time to be an area where silvicultural treatment of JANUARY - JUNE 1958 the forest would result in marked improve- ment in composition and quality. Previous reports on studies en the Luquillo Mountains have shown the extremely slow growth oi even the dominant trees in virgin stands of this forest, suggesting that some may be well over 1000 years of age. The growth rate of trees in virgin stands, while of scientific interest, is not a good basis for predicting what to expect in forests under management where the better trees have been provided with growing space by the removal of less desirable competitors. Thus a well balanced stand was subjected to an improve- ment cutting in 1947 and the results were cbserved and measured during the subse- quent 10 years. The cutting removed all trees of more than 20 inches, d.b.h. and left a basal area of about 80 square feet per acre. The better trees were liberated from suppression. No espectacular response to this treatment has been seen. The crowns of the trees, many of which were small or narrow due to previous suppression, did not increase rapidly in size in response to the additional light. The forest now appears about as open as it did at the time of cutting. There is no vis- ible sign of new tree seedling. Instead, soil beneath the larger openings has become cov- ered with such dense stands of razor grass Scleria sp.) that the future prospects for na- tural regeneration are not favorable. The average diameter growth rate of the dominant and codominant trees during the 10 years after treatment was only 0.06 inch per year, about the same in the virgin forest. Thus the native vegetation here appears to be almost non productive. It is very valu- able, however for the conservation of soil and water resources in these rainy areas. FOREST UTILIZATION RESEARCH It was not until 1954 that a full-time tech- nician was assigned to forest utilization re- search. Previous to this time investigations in this field were limited to a few preliminary tests of preservative treatment. The research hy) program includes the following active pro- jects within this field: 1. Machining of wood: The determination of the suitability of native woods for ma- chining with saws, planes and other wood- working tools and of techniques for overcom- ing any difficulties encountered. 2. Preservative treatment: The adaptation and development of methods to increase the durability of wood and wood products ex- posed to deterioration from fungi, insects, and marine borers. 3. Air seasoning of lumber: The develop- ment of techniques for rapid air seasoning of native woods with a minimum of degrade. 4. Charcoal production: The adaptation of practical techniques of charcoal manufac- ture developed elswhere to the utilization of local low-grade wood. The research in each of these projects is directed toward increased utility and value of forest products. Such increased value will constitute a direct economic gain and also will make more attractive the production of forest products locally with all its attendant benetits in terms of conservation. Machining Of Wood During 1956 tests were made of the 62 most common native and exotic timbers to determine their machining characteristics. The manuscript describing the results of these tests, originally prepared for a technical bulletin, is being reworked by F. R. Long- wood in more popular style for more general use. Another manuscript by the same author aescribing the characteristics and uses of 75 timbers of the Caribbean region has now passed review and is in the process of publi- cation. No additional machining tests were made during 1957. Preservative Treatment Preliminary efforts were made years ago to determine the service life of fence posts, treated and untreated. Re-examinations of some of these service tests during the year 20 showed that cold-soaking with pentachlore- phenol produced posts of several species which have endured exposure on the north coast and in the central mountains for more than 5 years, about double the expected service life without treatment. Since these posts are still sound, observations will con- tinue. A test of eucalyptus, treated with carbolineum by the hot-and-cold bath method showed posts on the north coast and interior to be sound after 7 years, more than double the life of untreated posts. The development of post treatment as a practical enterprise requires a more compre- hensive study of the absorption and penetra- tion of different preservatives by native post species and of their subsequent service life. In view of an estimated potential market of 830,000 treated posts (20-year service life) the preparation for this study was the main project in forest utilization research during the year. An experimental hot-and-cold bath treating plant was constructed at the Center. The two tanks are 4.5 feet deep, 4 feet wide, and 8 feet long. The hot-bath tank is equipped with eight 5000-watt inmersion heaters. The first study plan for use of the plant calls for the testing of 50 post species by the hot-and-cold bath and cold-soaking processes with both creosote and pentachlo- rophenol. By the end of the year about 300 test posts had been cut and peeled for drying and treatment. The Center cooperated with the Division of Forests, Fisheries and Wildlife of the Com- monwealth in preparing specifications for an experimental pressure treating plant to be used jointly by the Division and the Center. Studies of pressure treatment will develop methods for better use of existing facilities for this process and may show a justification for additional commercial plants for the treatment of local or imported wood. Air Seasoning Of Lumber The lumber of 62 common local timbers was dried for machining tests in 1955 and 1956. Preliminary information upon rate of CARIBBEAN FORESTER air seasoning and degrade were collected at that time. These data are in the process of publication. During 1957, as a result of an inquiry ‘rom a furniture manufacturer, the drying rate and degrade during seasoning of Colombian cedro macho (Carapa guianensis Aubl.) were studied. It was found that material arriving in Puerto Rico with a moisture content of 44 percent could by proper piling be dried to 21 percent moisture content in 49 days. This test was made in October and November. The equilibrium moisture content at San Juan, based on yearly weather records, was found to range from 14.5 to 17 percent. The driest period is during February, March, and April, and the wettest during September and October. Tests were made on 47 woods comparing the moisture content readings obtained with the resistant-type electrical moisture meter with those obtained by the standard oven-dry method. The results of this test have not been summarized, but in general the electri- cal moisture meter gave readings from 2 to 5 percent higher than those obtained by the oven-dry method at moisture contents of about 16 percent. Charcoal Production The charcoal market for domestic use has increased greatly in the United States in the last few years. During this year four sepa- rated interests explored the possibility of manufacturing charcoal in Puerto Rico and shipping it to the States. Our denser woods are well suited to charcoal manufacture, and the yield and quality for charcoal should be better than that obtained from the less-dense woods in the States. Samples of charcoal produced by the old-fashioned pit method were sent by the Center to the interested parties and to the Forest Products Labora- tory for chemical and briquetting tests. In all cases the samples proved satisfactory. The Center obtained plans for the construc- tion of a modern charcoal kiln in Puerto Ri- JANUARY - JUNE 1958 co to be constructed by the Commonwealth Division of forests for joint experimental use. COOPERATIVE FORESTRY AND TECHNICAL ASSISTANCE The work of the Center which is classified as strictly research terminates with the com- pletion of the studies and the presentation of their results in a form understandable to the person who needs the informaticn. The publication and distribution of research re- sults sometimes discharges this responsibili- ty. However, effective prompt application of what is known requires demonstration, direct advice, and in some cases financial as- sistance. The Center has been active in all of these ways to improve forest production and utilization in Puerto Rico and the Virgin Islands. Specific projects of this nature are as follows: 1. Cooperative production and distribution forest planting stock. 2. Cooperative forest management. 3. Demonstration of public forest adminis- tration. 4. Technical assistance to processors and users of forest products. 5. The Virgin Islands forestry program. The accomplishments of all of these pro- jects have been greater than in past years. Planting Stock As in previous years, the Forest Service cooperated during 1957 in the production and distribution of forest planting stock to private land-owners. The Forest Service made available an allotment of $25,000 for Fiscal Year 1957 share with the Common- wealth Division of Forests up to 50 percent oi the cost of this program. During that fiscal year a total of 435,000 trees were pro- duced and distributed by this program. Cooperative Forest Management A new program of technical assistance, termed “Cooperative Forest Management”, 21 was inaugurated during Fiscal Year 1957, under a cooperative agreement between the Forest Service and the Department of Agri- culture and Commerce of Puerto Rico. Un- der this agreement a federal allotment of $8,500 was made available to the Common- wealth to share the costs of technical forestry assistance to landowners. A farm forester was appointed by the Commonwealth and during the first year some 200 requests ‘or such assistance were fulfilled. A separate study by the Center during the year showed that tree distribution to farmers without prior Inspection of the land, attention at the time of planting, and follow-up to assure sub- sequent care, all by a trained forester, gen- erally did not result in a successful planting. The cooperative forest management program provided that service in 8 municipalities where tree planting is most important. An encouraging result was a survival check which showed an average of 71 percent during 1957, in spite of one of the driest years on record. A separate but related program of forest planting on private lands was encouraged directly by the Center in areas of Puerto Rico where tree planting is desirable but has not been done in the past. Eleven farmers were selected for the establishment of demonstra- trion woodlots. In the selection a_ special effort was made to find farmers whose inter- est in trees appeared genuine. Only one-half acre per farm was set as a goal. In spite of special care in handling the stock for these plantings, technical assistance at the time of planting, and follcw-up, only two of the plantations were successful. The conclusion reached was that until a good forest cash crop on a short rotation can be developed for these areas farmer interest will not be adequate to carry cut all of the necessary steps to assure reforestation. At present the only area where this favorable situation exists is in the tobacco region where the Co- operative Forest Management program has concentrated its efforts, and where there is a large demand for stakes and poles fer tobac- co barns. 22 Public Forest Administration The Caribbean National Forest, of which the largest unit is now termed the Luquillo Experimental Forest, is being administered in accordance with Forest Service policies for effective land management. These policies, applied to meet local conditions, are suited for all of the public forest lands of the Island. A plan for multiple land use within the Luquillo Division of the forest lays out spe- cifically areas best suited for each type of use. It provides for the protection of criti- cal watershed areas. It also provides for re- search in the ecology of the virgin forest, in silviculture, and in forest regeneration. It sets aside a large pilot-demonstration area for applying the results of forest research. It provides for the development of recreation resources and for the protection of wildlife. Protection of the forest, which is a prere- quisite to all other uses of the area, was sys- tematized by a scheduled boundary patrol plan covering some 73 miles of monumented boundary. Critical watershed areas, the steepest slopes and the high ridges and peaks, are reserved from all timber cutting or other use which could jeopardize soil protection. An area of 2,100 acres of virgin forest in- cluding 4 distinct types of forest has been reserved permanently by the Chief of the Forest Service for scientific study. Research in forest improvement and in tree planting is in progress in a part of the area reserved during 1957 for this purpose. The pilot man- agement program, described in more detail elsewhere in this report, has just completed its second year. The forest was compart- mented, large-scale maps were prepared and records of investments and yields are now being kept in detail. Timber sales were coordinated with the pilot management pro- gram and procedures were simplified. Forest trails were maintained. An area of 1,500 acres is reserved for recreation. During the year plans were made for much needed ex- pansion of recreational facilities within this are and were submitted to the Park Admin- CARIBBEAN FORESTER istration. Maps of the summer home areas were prepared and each was brought up to standard as regards maintenance of improve- ments. Direct liaison with the Commonwealth Di- vision of Forests, Fisheries and Wildlife in the field of forest administration took the form of participation in three joint training sessions for rangers and guards, three inter- forest visits by the field men, the training of two staff men during the spring course for foreign students, and provision of three months of summer forestry work for a col- lege graduate who then took employment with the Division. Technical Assistance To Processors And Users Of Forest Products Two circumstances have made_ technical assistance to processors and users for forest products in Puerto Rico and the Virgin Is- lands nearly as important as research in this field. The first is the lag between local practice and progressive development already proven elsewhere and apparently adaptable to local conditions. Examples are the use of proper seasoning methods, efficient plant layout, and use of the best machine for each job. The second circumstance is the great impetus given to all industrial development in Puerto Rico by the Commonwealth gov- ernment. The Center was active in 1957 both in advising existing processors and users of wood and in consulting with industrialists considering establishment of new industries here. The appearance of the article by the Cen- ter on “Industrial Wood Use in Puerto Rico” in 1956 (Caribbean Forester 16:64-97) and a subsequent study of forest utilization made cooperatively by the Puerto Rico Industrial Development Company and the Center, set the stage for a flood of inquiries concerning wood utilization, most of which have reached the Center through the Development Com- pany. JANUARY - JUNE 1958 Initial inquiries about wood _ utilization usually concern quantities available. To pro- vide all available information of this nature the Center summarized by key species the data from the 1948 cruise of the Luquillo Forest and from the Commonwealth forest inventory of 1948-1952. While incomplete and not up to-date, these data were used in 1957 to service tweive inquiries received from the Development Company and other sources. These inquiries concerned a variety of pro- ducts, including airplane models, millwork, furniture, charcoal, veneers, excelsior, coat hangers, novelties, shoe lasts, and particle board. The most spectacular result from the tech- nical assistance of the Center in this field during the year was the development of a market for a tree species heretofore consid- ered inferior. Tests of material supplied by the Center showed that yagrumo hembra (Cecropia peltata L) is suitable as an excel- sior for bonding with cement to form an in- sulating and structural board. The result has been the construction of a plant, now nearing completion, by the Insuldyne Corpo- ration capable of consuming 10,000 cords of wood per year. It is expected that other local woods will prove suitable for excelsior also, thus providing a market for several species of trees. Subsidiary to the Insuldyne Corporation is the J. Diener Lumber Company with a new sawmill and a demand for mixed hard- wood sawtimber for pallets and crates. Pre- liminary negotiations with this company in- dicate a willingness to try harvesting mixed species as they occur in the forest, a situa- tion which should make logging much more economical than in the past. Frequent inquiries have concerned the moisture content of native or imported lum- ber. Use by the Center of a moisture meter has made possible valuable service in this field. Some of our cooperators are obtaining their own equipment for this purpose. bo ive) The Virgin Islands Program Under a cooperative agreement with the Virgin Islands Corporation the Center con- ducts a broad forestry program, at Corpora- tion expense, in the Virgin Islands. The ob- jective of the program is to encourage better use of forest lands and forest products. The program is composed of two main projects: forest land improvement, and logging and milling. The work is centered on but not confined to the island of St. Croix. Forest land improvement works has con- sisted primarily of the introduction of ma- hogany (Swietenia mahogani Jacq and S. macrophylla King) into brushy areas on steep slopes. The planting stock, produced locally, is provided without charge to the landowners. The year 1957 was especialiy unfavorable for planting because of drought. Precipitation in St. Croix was only about one third of the normal, and most of the rain fell within a two-month period. Neverthe- less some 16,000 mahogany trees were planted on approximately 50 acres during the period of September to November. Teak has proven adapted to certain better soils in St. Croix. Some 30 acres have been planted to teak in the Thomas Estate Ex- perimental Forest, including 8,500 trees during the past year. An additional small planting was made on private land. Both teak and mahogany are viewed as favorable woods for a novelty industry which, geared to the tourist trade, could provide a large amount of local employment. A naturally established forest of Domini- can mahogany covers some 300 acres in St. Croix, partly within the Experimental Forest. A previous improvement cutting of about 100 acres of this forest removed many trees of undesirable species. A release cutting, be- gun on 6 acres in 1957, is removing mis- shapen trees, both large and small, to favor the others. The Virgin Islands do not bear heavy tim- ber stands, yet the scattered old trees of ma- hogany and other species suited for cabinet 24 work are a resource which heretofore has been largely wasted for lack of facilities for logging and the manufacture of lumber. The Project provides this service at cost and is gradually building an inventory of lumber suitable for a novelty industry. Some 150 logs were sawn during 1957, mostly on a cus- tom basis. FORESTRY TRAINING All of the Center’s facilities and resources were again used to the fullest extent in the accomplishment of our foreign training mis- sion. The third tropical forestry short course sponsored by the International Cooperation Administration was conducted from March 13 to May 31. This course was attended by eleven participants from ten countries from South and Central America, the West Indies, Asia, and Africa. CARIBBEAN FORESTER Students attending the regular course re- ceived some training in all phases of forestry nursery and planting, silviculture, forest management, mensuration, utilization, policy and legislation, and the organization and ad- ministration of forest services. The curricu- lum also included the conservation of re- sources allied with or dependent upon forests. In addition to the regular course, seven other persons interested in tropical forestry visited the Center for observation or study for periods ranging from a few days to two months. Valuable assistance, particularly during the short course, was given the Center by the Food and Agriculture Division of the United Nations and various agencies of the Common- wealth government especially the Division of Forests, Fisheries, and Wildlife of the De- partmen of Agriculture and Commerce. JANUARY - JUNE 1958 bo Or The Fifth Tropical Forestry Short Course By: F. RALPH THROOP, Training Officer U. S. Forest Service Puerto Rico Vast sums of money are being spent by the United States and by international agen- cies to assist different areas of the world to improve standards of living by providing eco- nomic means and technical know-how. Many people recognize this assistance as prompted by moral or political reasons, or both. Some question the value of such assistance, believ- ing that it can only make the recipients de- vendent upon continuation of such gifts. There can seldom be any doubt as to the moral basis of such assistance and its lasting value when the money is spent to teach and show peoples how to improve their own eco- nomic conditions through better management and utilization of their own resources. The International Cooneration Administration of the United States and the Food and Agricul- ture Organization of the United States are two of the important agencies adminis- tering aid of this type. One project in which they both work together is in the series of tropical forestry short courses offered at the Tropical Forest Research Center of the U. S Forest Service at Rio Piedras, Puerto Rico. The fifth tropical forestry short course was presented in the spring of 1958. Pre- vious courses have been described in The Caribbean Forester 16 (1&2) 12-23 and 18 (1&2) 33-39. All of these courses have been considered successful in the sense that they have satisfied a need of the participants. The students have returned to their respec- tive countries with new and different views as to how to solve their problems. The par- ticipants, instructors, and coordinators all have had their eyes opened as to the problems confronting the many countries represented. Many international friendships have resulted. The returning participants generally will not be able to apply immediately many of their new ideas toward the solution of their local problems because of one reason or the other, but they stand better prepared to take advantage of an opportunity when it does knock. They also know where they can go to get additional technical aid when~ they need it. These results appear to constitute entirely satisfactory goals for short training courses of this type. The course was under the direction of the Tropical Research Center. This agency, financed for this purpose by the Interna- tional Corporation Administration, furnished most of the facilities, set up the program, and did much of the actual instruction and training. In this activity the Center was as- sisted by the Office of Technical Cooperation, Puerto Rico Department of State; the Divi- sion of Forests, Fisheries, and Wildlife of the Department of Agriculture and Commerce ot Puerto Rico; the Soil Conservation Service and the Agricultural Stabilization and Con- servation Service, both of the U. S. Depart- ment of Agriculture; and the Agricultural Extension Service of the University of Puer- to Rico. These agencies provided, within their special fields of activity, instructors, training material, transportation, and tech- nical assistance. The bulk of the training was done by the technical officers of the Research Center, but beside these and the cooperators, three other technical people participated this year: Mr. John C. Killebrew of the Forest Products Laboratory in Madison, Wisconsin instructed in wood utilization; Mr. Earl J. Rogers of the Department of Forest Economics Research of the Forest Service in Washington instructed in forest mensuration; and Mr. A. Hyndman Stein, FAO forester with the Inter-American Institute of Agricultural Science at Turrial- 26 ba, Costa Rica lectured on forest policy and directed and summarized the round table dis- cussions of individual country probiems. The objective of this course was to offer, in so far as possible, a balanced program aimed at satisfying the greatest needs of most of the participants. As the individual needs of each country and the basic technical train- ing of each participant varied, it was impos- sible to give everybody exactly the emphasis most desired. However, in being general in its coverage, the course was directed toward the basic aims. The scheme of presentation included an attempt to define and show forest problems, to clarify their magnitude and the priority of their solution, and to offer some suggestions for action. Three training techniques were used: 1. Lectures by technical personnel using slides, films, personal experiences, re- search findings and material from texts. 2. Field trips to problem areas so_par- ticipants could see first-hand what could be done. Where practical, the students actually participated in the “doing”’. 3. Round table discussions using the participants own problems as the sub- ject. This allowed each participant to see other’s problem and to consider suggestions and exper‘ences of the group relative to its solution. Much of the presentation, for lack of tropical experience, had to be based upon findings in the temperate zone. Where this was necessary a special effort was made to interpret the material in a form applicable to the tropics, and to recognize the distinction between universally applicable principles and those details which must differ from place to place. The presentation was geared, «n so far as was possible to the stage of advance- ment of the countries represented. The stu- dents themselves participated in discussions concerning their special experiences and con- CARIBBEAN FORESTER ditions throughout the course. They were at all times kept aware of the magnitude of Puerto Rican forest problems and the need for parallel progress toward their solutions. This year 21 trainees from 12 countries attended the course, as follows: Gilberto Acosta Ayala - Puerto Rico Ranger, Commonwealth Division of Forests Diniz Xavier de Andrade - Brazil Professor of Silviculture, Northeast College of Agriculture, Paraiba, Brazil Jorge Enrique Becerra - Colombia Forestry Superintendent, Servicio Técnico Agricola Colombiano Americano Domingo Bermtdez - Puerto Rico Ranger, Commonwealth Division of For- estry Moisés Augusto Berrios - Nicaragua Forestry Technician, Ministry of Agricul- ture, Managua, Nicaragua Eustace Araon Bradley - British Honduras Forester, Government of B. H., Belize Joseph Clairmonte Clarke - St. Lucia Forest Guard, St. Lucia Goverment Forest Service Jaime Galindo - Colombia Assistant Forest Superintendent, Rio Cali, Colombia Wenceslao Tovar-Mozo - Colombia Assistant Lawyer, Free Lands Section, Ministry of Agriculture Norman B. Vickers - Jamaica Divisional Forest Supervisor, Jamaican Forestry Department Conrado Goémez - Colombia Forest Superintendent, Manizales, Colombia Jacob Guerrero - Pert Superintendent of Iquitos Forest Gregor Armstrong Hall, - St. Lucia Ranger with Government of St. Lucia John Kingsley Howes - Montserrat Agricultural Assistant, Agri. Dept. Eduardo Izquierdo - Pert Superintendent of Pucalpa Forest Fitzroy Johnson - Trinidad Forester, Trinidad Forestry Department t N JANUARY - JUNE 1958 ‘(VeMIISUOTT ‘SOMOH UYOL - oINZoId WOIJ SUISSTII) “Brlonyt 4S ‘ayae[O Ydosor fuojsulyseM ‘SSA ‘s1asOy [Ieq !oons OJAIN” “ZYIO AOJOIA VIQCULOTOH ‘ZaUlOF) OPVIUOHD ‘SeLtaqryT ‘UVdy pavyoIyY ‘oory OJloNg ‘vVysooy OJAqIYD 1Yy Ol "JT - MOY JUOI “OOTY OJFAON| ‘SoIO[Y TeqOJsIID SVIqUUO[OHD ‘OpUT[eyH ouUlIee {eVNSTAVIIN ‘SOIIIag SOSIOP. {svBInpUuO_, Usa ‘AoTperg QVISNY VIQCUIO[OD “IVAOT, OV[S9OUBM ‘VIQUIO[OD ‘“VAILOD9G OS I0f ‘Niog ‘OLOIIANH qoove {190JO Sururery, oon oon ‘Susp, ‘doory, ydiey -Yy 0} "T - MOY pug ‘ooTY OJLONg ‘ZadoOT AOJOIA ‘vIONT 4S ‘eH IOs9aIH ‘oory OJang ‘Zapnultiag o3 -UIULO( SBOTIVUCLE ‘SIOYOIA UVULION ‘BorlewUeL ‘SyJaxory UBUIPVa4G ‘[IzZVIg ‘apvIpUY ZIUIq ‘pepluIayL ‘UOsSuUYyOL AOIZIW {n1z9g ‘opilamnbz] opienpy ‘lapvoyT Jayu9D Yorvasay ‘Sus ‘UWOMSpeM YyuUvIWA !BVoIY vISOD ‘OURTOG TBAZIT 2°Y OJ "TZ - MOY yor 28 Richard Kanwie Kpan - Liberia Forest Supervisor, Dept. of Agriculture and Commerce, Monrovia Victor Lopez Fumero - Puerto Rico Ranger, Commonwealth Division of For- estry Victor R. Ortiz Vazquez - Puerto Rico Ranger, Commonwealth Division of For- estry Steadman E. Ricketts - Jamaica Divisional Forest Supervisor, Jamaica For- estry Department Meyer Solano, Conejo - Costa Rica Chief of National Forest Department Ministry of Agriculture and Industrie3, San José SUBJECT MATTER AND GENERAL PROGRAM From the following description of the sub- ject matter, the reader can readily see the broad scope of the program. From question- naires and appraisals made out by the stu- dents and instructors at the end of each annual course, suggestion have been received which result in changes in the program each year. The following was the program for 1958: PHYSICAL ARRANGEMENTS AND ORIENTATION The first week was spent in getting the students settled. The Office of Technical Cooperation welcomed them and pointed out through lectures and visits the points of in- terest and other information the students should know about the island and its govern- ment. Lectures were presented on the edu- cation, industry, agricuture, and the history of forest conservation in the island. DENDROLOGY AND ECOLOGY — 4 DAYS Here were explained the bases for classi- fying tropical trees and forest associations. The students collected leaf specimens and learned the technique of preparing simple CARIBBEAN FORESTER field keys for their identification. The major tropical forest formations and associations were described. ARTIFICIAL REGENERATION — 6 DAYS Since such a large percentage of potential forest land has been depleted of trees and is in need of reforestation in so many countries, considerable times was spent on this course showing through all steps how it could be done. This covered seed collection, testing, sowing, nursery practice, field planting, and plantation care. Trips were made to a nurs- ery and to several established plantations. SELVICS AND SILVICULTURE — 6 DAYS This subject dealt with the natural char- acteristics of tropical forests and methods of improvement, including density, composition, and quality. Practices included were thinnings, removal of inferior species or de- formed trees, and selection of crop trees. Field work included inspection of unimproved and improved forests and actual work in both mixed stands and plantations. FOREST MENSURATION — 10 DAYS Included here were lectures and field prac- tice in land surveys, volume and growth de- terminations of standing trees, volume of logs, volumes of manufactured products, the layout of a forest survey, and the use of aerial photographs in mapping, determining forest areas, types, and volumes. FOREST MANAGEMENT — 2 DAYS This subject covered the operation of the forest on a business basis, how the cut and yield can be controlled, how to determine land values, and finance. Included was a complete description of the Luquillo pilot- management program, involving compart- mentation and use of area and volume control. FOREST RESEARCH — 2 DAYS Included here were the analyses of forest problems, the decisions as to relative priori- ties of different lines of investigation, objec- JANUARY - JUNE 1958 tivity in comparative research, how to start on a modest basis, and the necessary steps inherent to all reliable experimentation. FOREST UTILIZATION — 10 DAYS The various properties of woods and their significance to utility were described. Through the use of films and samples a large number of forest products were shown as well as equipment for their manufacture or process- ing. Visits were made to the pilot preserva- tive plant of the Center, the local paper mill, a furniture factory, and a new pressed board plant. A large number of pertinent Forest Products Laboratory pamphlets were issued to the students. FOREST PROTECTION — 1 DAY Discussion centered around the impor- tance of recognizing the extent of damage anc control measures for the three major injurious agencies: fire, insects, and disease. PUBLIC FORESTRY — 3 DAYS This covered the place of the government in the control and management of forested areas. The U.S. system of management was presented here as one example. The students were shown how the National Forests are or- ganized and administered. PRIVATE FORESTRY — 2 DAYS The four local agencies concerned directly with the management of private forest lands: the Division of Forests, the Extension Service, the Soil Conservation Service, and the Agri- cultural Conservation & Stabilization Service presented a panel discussion on their respec- tive roles in this field. Private forest plantings resulting from the Clarke-McNary and Coop- erative Forest Management programs were visited. SOIL CONSERVATION — 1 DAY A day in the field with technicians of the Soil Conservation Service to see problems and results of field work. 29 ALLIED FOREST RESOURCES — 3 DAYS Field trips were taken to observe what is being done in the way of utilizing forest lands for other than forest crops. Visited were a small, modern and efficient water treating plant, a fish hatchery, recreation areas, and soil protection areas. FOREST LEGISLATION AND POLICY — 1 DAY The vital importance of any country having prepared a sound policy regarding land use for forestry, water, agriculture, etc. was pointed out. Results of countries failure to do so were pointed out and highlighted. How policies can be developed were discussed. FOREST PROSLEMS IN TRAINEES COUNTRIES — 4 DAYS Participants from each country were given an opportunity to prepare a statement covering the more important phases of his country as regards to location, area, physical geography, and specific problems faced. This acted as a summary of the entire course as students were then able to see how the entire training program fit into the overall picture as dictated by the specific problems of each country. In this entire three-month program the participants spent a total of 64 percent of their time in the classroom and the rest in the field. Of the 1,260 mandays spent there were no accidents but there were at least 30 mandays loss through illness, or absence for personal reasons. One student submitted to a major operation which caused him to miss two weeks of class. The student who traveled the greatest distance to attend was the participant from Liberia, Africa. The staff of the Tropical Forest Research Center is looking forward to next year’s course. Each member feels that he has gained a great deal through knowing and working with the representatives of these neighboring countries and has experienced the feeling of doing something to improve the lot of his fellow man. 30 CARIBBEAN FORESTER Observations on Some Caribbean Forests By W. S. CHALMERS 1/ Department of Botany University College of the West Indies Jamaica SUMMARY The writer describes visits made to Haiti, the Dominican Republic, Puerto Rico, British Guiana, and Trinidad. Several aspects of the forestry programs in the different coun- tries were studied with the principal interest being the natural forests of Pinus occidenta- tis Sw. of Hispaniola and the establishment of Pinus caribaea Mort. in Trinidad and Bri. tish Guiana. The progressive forest policy adopted in Trinidad has resulted in an ad- mirable forest estate. ACKNOWLEDGMENTS The Cross Trust (Perth. Scotland) fur- nished the grant without which the trip could not have been made. Their interest is sin- cerely appreciated. Thanks are due also to the foresters in the various places visited. Their hospitality and enthusiasm contributed much to make the trip both instructive and enjoyable. INTRODUCTION During January and February 1958 a tour of some of the forest areas in the West In- dies was made to observe forestry practices and programs in those areas. The following account is based on observations and notes recorded daily. It is not intended to be highly technical nor critical but rather a presentation which may be of interest to for- esters in the area, who cannot gain the ex- perience by personal visits to their neigh- boring countries. 1/ Mr. Chalmers holds a Leverhulme overseas research scholar- ship at U.C., W.I. Hi Avie 1 The first stop was in Haiti to visit the natural forests of Pinus occidentalis in the southeast portion of the country. Through the cooperation of the Societe Haitiano-Ame- ricaine de Development Agricole (SHADA) several days were spent in the Foret de Pins in the Mornes des Commissaires area. This area ranges from 3250 to 6800 feet in eleva- tion and with a five to six-month dry season from December to April has an annual rain- fall of 65 inches. Although the normal win- ter temperature is between two and five de- grees, it may fall as low as two or three de- grees below zero Centigrade. Geologically the area is of Eocene lime- stone giving rise to a reddish brown clay loam soil of variable thickness. On steep slopes there is often only an inch of two of soil with frequent outcrops of sculptured limestone. On gentler slopes 12 to 18 in- ches of soil cover the red stained parent ma- terial which the pine roots apparently pene- trate with ease. The surface litter, com- posed mainly of pine needles and twigs. may form a layer up to three inches deep. THE TREE CROP Pinus occidentalis is believed to exist na- turally only in Hispaniola and eastern Cuba (1) 1/. It is a species closely allied to P. caribaea Mort. and is commonly known in Haiti as ‘‘bois pin”. According to the Flora D’Haiti (2) its altitudinal range is above 2600 feet. The tree occurs in pure stands over many thousands of acres broken occa- sionally by farm lands or rain forest. With 1/ Numbers in parenthesis refer to references in literature cited. JANUARY - JUNE 1958 the falling or burning of the rain forest, the pine rapidly encroaches to the exclusion of most other species except Didymopanax trem- lum Kr and Urban. Mature specimens are invariably of excellent form with a DBH of 5 to 6 feet, a total height of 90 to 110 feet, and a clear bole of up to 50 feet. These mature trees posses typically flattened crowns. A noticeable feature is the abundance of natural reproduction of all age classes throughout the crop even under quite dense pole-size stands. Unfortunately most of this regeneration is lost or becomes very spindly because of the intense competition since there is insufficient labor to undertake the necessary thinning or release. This is espe- cially true in burned areas. Natural regen- eration is not so prolific in wet depressions and valley bottoms nor are the mature trees of such large size as on the slopes and ridges. Among the commonly occurring ground vegetation plants are the following: Bocconia frutescen Lx., Agave sp., Ilex sp., Rubus sp., Lycopodium sp., Ipomoea sp., Vaccinium sp., Fragaria sp., Pterdium sp., and Didymopanax tremulum. In addition there are a number of species of grasses. The Agave sp. are most frequent on the dry steeper slopes. Seed Production Local residents believe that at elevations above 5000 feet the trees do not bear seed until they are 30 to 40 years old. At lower elevations it seems likely that fruiting occurs at younger age though site quality may af- fect age of fruiting. (Four-year old P. occi- dentalis planted at an elevation of 1500 feet in Jamaica bore a few cones last year). Male and female flowers were abundant at the time but, according to the natives, seed years vary widely. Seed is collected from December te March only from trees felled during the annual coupe. Special equipment would be _ neces- sary to collect seed from the best trees be- cause of their great height. It is unfortu- ol nate that such equipment is not available because SHADA, which is responsibie for the management of these forests, has rarely been able to meet the annual demand for seed. HARMFUL AGENCIES Fire is by far the most destructive agency. Mature trees appear able to survive the severest scorching because of their very thick bark. Young trees with thinner bark are less resistant and extensive areas in the younger age class have been destroyed by fire. Areas with young regeneration are highly susceptible tc damage because ground fires spread rapidly and often spread into the crowns. December to April is the most hazardous period and in 1950-51 nearly 11,000 acres were affected by fire during this season. During 1957 there were 17 out- breaks in April and 9 in May. The princi- pal causes are listed as farmers, travelers, and incendiarism by local people. Grazing of cattle in the forest is common and the occurrence of isolated dead trees is invariably caused by the girdling of the tree by the tethering rope. The forests have until recently been rela- tively free from insect and fungus epidemics. During 1957, however, widespread deaths occurred among younger trees due to a scale insect which was identified in the Dominican Republic as the cottony cushion scale, [cer- ya purchasi Maskell. This insect, a func- tional hermaphrodite, is no doubt partially controlled by a dipterous parasite Crypto- chaetum iceryae Williston (3). White cot- tony egg cases were seen everywhere though once vacated they are easily washed or blown off. An attack is then evidenced by small yellow puncture holes. Needles brown and fall quickly, usually from the lower branches upward though in some instances the re- Reverse occurs. Trees attacked by the scale insect seemed to be very susceptible to a root fungi and rot quickly at the ground level. Resinous gall-like structure were found occasionally in newly developing lateral and terminal buds and among the young clusters of leaf fascicles. These structures which may be of traumatic origin as a result of the egg laying of a spider, invariably lead to the atrophy of the stem where they occur. TIMBER In Haiti the wood of P. occidentalis is known as “bois chandelle”. In the moun- tains it is used for fuel; throughout the country its use for construction purposes is increasing. An examination of several stumps showed the growth to be generally very uni- form averaging 6 to 7 rings to the inch. Growth rings were clearly defined with false rings sometimes discernible. Wellwood (4) in a study of the wood properties concluded that in most respects it equalled the wood of the British Honduras pitch pine P. cari- baea. Harrar and Reid (5) showed that the timber will retain amounts of creosote oil far in excess of the minimum specified by the American Wood Preserver’s Association. PLANTING P. OCCIDENTALIS IN THE TROPICAL COUNTRIES In recent years seed has been sent by SHADA to many countries in search of a fast growing conifer having desirable wood properties. Recipients include Peru, Ecua- dor, Brazil, Australia, New Zealand and East Africa. Australia reported a high percent- age of failures with seedlings planted on a number of coastal areas between 17 and 27 degrees latitude South. In Jamaica, how- ever, small trial plots at elevations between 1000 and 2000 feet on a variety of soil have shown exceptionally good growth. In 1957 trees in one 4-year old plot overaged nearly 4 inches in d.b.h. and 20 feet in height; max- imum sizes were 5.5 inches and 27 feet re- spectively. From observation in its native range it appears that P. occidentalis should be a de CARIBBEAN FORESTER sirable species to test and would probably succeed best on site elevations above 2000 feet with moderate rainiall. DOMINICAN REPUBLIC A short time was spent visiting the P. oc- cidentalis forests in the center of the coun- try near Jarabacao and Constanza. Here, at an elevation of 4000 to 6000 feet, the pine grows on a clay loam soil derived from rocks of volcanic origin. The maximum temper- ature during June, July and August reaches 27 to 29 degrees C. while in December, Jan- uary and February frosts are experienced. Although not as large here as those seen in the Forest des Pins, the trees were of fine form. Natural regeneration was prolific and here too the pine forests were reported to be spreading following clearing of the Rain Forest. The field layer in general was sparser than that encountered in Haiti. Some of the most common species present were Boc- conia frutescens, sp., Bidens pilosa, Vaccinium sp., Agave sp., Odontosoria fumarioides, Pte- ridium sp., and Blechnum sp. In addition there were several species of grasses and one or two Melastomaceous shrubs. Russula sp. was a common ground fungus. SEED BEARING At that time, early January, dense clusters of dull red unopened male flowers were 2 common sight. In this region trees, cer- tainly less than 20 years old, bore cones in varying quantities. The cones remain firmly attached to the branches after seed dispersal. This is rather deceptive since the cones tend to reclose after seed fall. At Constanza an interesting experiment was in progress to determine the effect of removing the leading shoot at 3 or 4 years on flowering and fruiting. Five-year old trees about 15 tall had extremely heavy side branches, were laden with male and female JANUARY - JUNE 1958 flowers, and bore a few mall cones. This heavy induced flowering was the first step in an effort to obtain a quicker, more acces- sible source of seed. HARMFUL AGENCIES Less evidence of fire damage was seen in the Dominican Republic. Neither was there much evidence of injury by the cottony cushion scale. Instructions have been issued that forest guards report the first sign of in- fection so that immediate control measures might be instituted. The resinous gall-like structures were just as common as they were in Haiti. TIMBER Emphasis has been placed on utilization and two modern sawmills were visited, one at Tireo the other at Constanza. The 3-year old mill at Tireo is the second largest in the country. Diesel powered, the mill has a ca- pacity of 100,000 cubic feet per month but was producing only 40 to 50,000 feet; 90 to 100 men are employed. The mill handles only pine logged in the surrounding districts. Much of it is sawn to specified sizes for use in the Government home construction pro- grams. Both of the sawmills visited were equipped with large, modern, dry kiins. Most of the sawn timber showed very uni- form growth rings varying from 6 to 8 per inch. The product from one particular coupe being felled was extremely knotty. Another defect noticed in some boards was the occa- sional presence of resin plates best described as resembling tight translucent knots. VARIATION EN P. OCCIDENTALIS In both Haiti and the Dominican Repub- lic there was a noticeable variation in bark characteristics and needle form. The former may be simply a matter of age. The length, texture, and number of needles per fascicle varied. Needies were usually 8 to 9 inches long and fairly coarse but a more delicate, finer type 5 to 7 inches long was seen occa- sionally. In both countries random counts were made of the number of needles per fas- cicle; they varied from 2 to 5 per fascicle with 3 the most common, though fascicles with 4 needles were surprisingly common. A similar condition occurs in P. caribaea Mort which is described as having 2, 3 or more needles (1). THE FOREST ESTATE The Dominican Republic is fortunate to have over 65 percent of its land still under forest cover. These forest resources are gradually being developed to a greater degree than heretofore, especially with the provision of an extensive system of forest roads. The minimum size of tree than can be felled is specified by law. In addition any area that has been clear-felled may remain under cuitivation for two years and must then be reforested or put under permanent pasture in an attempt to prevent erosion. PUERTO RICO Two weeks were spent in Puerto Rico with personnel of the Tropical Forest Research Center of the U. S. Forest Service. The ‘irst week was devoted primarily to reference work in their excellent library. In the field two current projects were of special interest since they may in the future have an effect on forestry in other Caribbean countries. UTILIZATION OF CECROPIA PELTATA L. Prior to a year ago this species, known locally as yagrumo hembra, was just another weed tree; more prolific and faster growing, perhaps, than most other species in that class. However, in terms of volume, it is near the top of the list of Puerto Rico’s for est trees. It was decided that any forest utilization program should consider the use 34 CARIBBEAN FORESTER Fig. 1 - Yagrumo logs piled at “Insuldyne” plant awaiting processing into excelsior. Ponce, Puerto Rice. 1958. Figure 2. - Forest officers inspecting the cement-excelsior product “Insuldyne produced at the Ponce plant. 1958. JANUARY - JUNE 1958 of this tree a worthy project. A study of its properties and actual tests showed that it could be shreced easily and used as a subs- titute for the excelsior previously made from temperate pine species, mixed with cement in the manufacture of a building board known as Insuldyne. A modern factory has been erected near Ponce on Puerto Rico’s south coast which will require 10,000 cords of wood annually. Fig. 1 and 2. Trees 5 inches d.b.h. and larger can be utilized. On the Luquillo Experimental Forest trees to be harvested are selected and marked by forest rangers and sold.on the stump to the highest bidder. All woods operations are Sys) performed by the purchaser or by labor hired or under contract to him. Felled trees are bucked into 5 foot bolts and extracted to the roadside by oxen, hand, or by gravity on wire cable and then beaten with a club to remove the bark. The peeled bolts are then stacked and measured in cords and later transported to Ponce by truck. Larger trees are con- verted into logs and sold by the thousand board feet. Investigations are being made in an attempt to improve logging operations by mechanization where possible as extrac- tion on the steep slopes and mountainous terrain is troublesome and expensive. Ac- cessibility at present limits the sale areas to (Fig. 3) those near roads. Fig. 3. - Yagrumo bolts stacked along road waiting transporta- tion to mill. Luquillo Forest. 1958. 36 On one area visited in the Tabonuco type in the Luquillo Experimental Forest had Ce- cropia trees up to 24 inches d.b.h., much larger than any seen in the other countries visited. Preliminary investigations into the natural and artificial regenerations of Cecropia have been instituted to determine how to increase the supply in existing forests and for refores- tation of steep lands which should be under forest cover. Inquiries are also being made into the possibility of importing this timber from other countries. TIMBER STAND IMPROVEMENT Very little virgin forest remains in Puerto Rico and the secondary forest stands include many trees regarded at present as undesir- able due to species or poor form. Much can be done in such heterogeneous degraded tropical rain forests to improve the composi- tion by the removal of some of the undesir- ables to favor the better trees. In Puerto Rico this subject of timber stand improve- ment has been given considerable attention particularly as to the best methods of effect- ing the improvement operation. For a number of reasons normal felling is not always considered the best method to employ from either the silvicultural or econ- omic view-point. In recent years a great deal of research has been done particularly under temperate conditions on the use of poisons and chemical growth regulating com- pounds to kill unwanted trees. Cne such experiment was initiated in January 1958 by the Tropical Forest Research Center designed “primarily to test certain methods using chemicals, concentrations and_ techniques which have given fairly consistent kills in other places or modification of such methods which if successful would simplify their trop- ical application”’ (6). In this study seven treatments were tested on a number of species. Treatments included a simple double-hack or chip girdle and six chemical treatments using ammonium sulfa- CARIBBEAN FORESTER mate (Ammate) and 2,4,5-Trichlorophenoxy- acetic acid (2,4,5-T). In the chip a con- tinuous ring of wood 2 to 3 inches wide and one-half inch deep is removed. The 6 poi- soning treatments were as follows: 1. Single frill girdle with 19.3 percent so- lution of Ammate. 2. Single frill girdle with a 2 percent mix- ture of 2,4,5-T and water. 3. Basal incisions with a 10 percent mix- ture of 2,4, 5-T and water. 4, Basal bark spray with a 5 percent mix- ture of 2,4,5-T and oil. 5. Incised bark spray with a 20 percent mixture of 2,4,5-T’ and water. 6. Normal bark spray with a 20 percent mixture of 2,4,5-T and water. The treatments were replicated and applied in late January during the dry season when trees were least active. Records were kept as to the amount of time and chemical re- quired for each treatment. Treated trees will be examined after 2, 6, 12, 24, and 36 months to determine amount and rate of crown kill, sprouting, and the rate and method of deterioration and fall of killed trees. Results which the Research Center intends to publish in the second or third year will no doubt prove valuable to others concerned with the improvement of degraded secondary forest in tropical regions. Two other items in Puerto Rico were of special interest. The first is the Research Center’s work with pine. No species of Pinus had ever been successfully established on the Island despite several tests with a variety of species over a number of years. There is now, however, in the Maricao forest a small but interesting plot of Pinus elliotti: Engel., that has reached a stage of development nev- er before attained. These seedlings along with a number of several other species were planted in 1954 and the next year exhibited the usual unthrifty appearance. In July 1955 the soil around some of the P. elliottii seedlings was innoculated with mycorrhiza- bearing humus and A-1 horizon soil material JANUARY - JUNE 1958 obtained under plantations of P. echinata and P. taeda in the southeastern United States. A number of trees were left un- treated as controls. The plot has been ex- amined and the trees measured regularly. When examined in January 1958. though the best trees couid not all be described as vigorous, they were in every case trees whose (oS) ~ roots had been innoculated with the mycor- All the check seed- lings were very unhealthy; some had died. (Fig. 4). need for research into the role of mycorrhiza rhiza-bearing material. This experience emphasizes the in the establishment of pine species on the Island. Fig. 4. - Effect of mycorrhizae applied to soil around pine seedlings (Pinus ellioti). Seedling at left 5 years old (untreated). The final item ccncerns an aspect of fores- try not often in evidence in the West Indies, namely Amenity. The accessibility and ex- cellent facilities—restaurant, swimming pool, picnic shelters, cabins, etc. available for use by the public at the La Mina Forest Recrea- tional Area in the Luquillo mountains, could well be emulated in other countries. Cer- tainly in Puerto Rico the annual total of vi- sitors to La Mina proves the popularity and Seedling at right same age (treated). good use made of such facilities, which at the same time must surely make people more forestry conscious. BRITISH GUIANA Fourteen days was too short a period to ever attempt to get an overall picture of forestry in this vast country where 80 per- cent of the land is forested. Most of the 38 available time was spent in the Greenhart (Ocotea rodiaei Mez.) forests in the Bartica Triangle and visiting the recently established Forest Department plantations of Pinus car- ibaea near Bartica. DEMERARA GREENHART Fanshawe (1) describes the greenhart as an evergreen canopy tree (attaining heights of up to 130 feet and diameter of 40 inches) occurring as a dominant and moderately gre- garious species over small areas of rain and evergreen seasonal forests on light sandy loam soils, being occasional to locally fre- quent in other types of forest on any kind of soil. The species prefers a mesophytic habitat though it grows under conditions of physiological drought as in the Mora (Mora excelsa Benth) and Wallaba (Eperua falcata Aubl.) forest. Through the kindness of British Guiana Timbers, Ldt. it was possible to visit their current logging site near Ikuribisi. Briefly their harvesting procedure is as follows: The virgin forest is surveyed and demarcated into compartments. A 25 percent strip cruise is made to estimate the merchantable volume of greenhart in each compartment and to de- termine the most suitable locations for roads and storage points (termed markets). After felling the giant trees are hauled by huge tractors to a market where they are measured and booked. Eventually they are transported by powerful lorries to Winiperu on the River Essequibo to begin the final stage of the journey by barge to the Houston mill on the River Demerara. At this sawmill, said to be the largest in South America, the logs are converted to sawn lumber often directly to specifications for particular projects. Besides being sawn into lumber, greenhart is supplied in the round for use as piling and also as hand hewn squares. PINUS CARIBAEA The first trial plot of P. caribaea in Bri- tish Guiana, planted in 1954, used trans- plants raised from seedlings flown in from CARIBBEAN FORESTER Trinidad. The planting site was cleared of the secondary bush and the six months old transplants planted at a 6 by 8 foot spacing (7 by 7 feet is now standard practice) and dressed with two ounces of superphosphate. The trees were pruned when 3 years old and in February 1958 varied from 15 tc 20 teet in height and from 3.5 to 5 inches d.b.h, The trees were not of good form; double leaders were fairly common and a number of trees showed a pronounced curvature near the base. There appeared to be no correla- tion between the age of the tree and the number of branch whorls. Nearby on the former transplant beds a number of plants had been left under fairly heavy shade. Though the same age as those on the nearby plot, the trees under shade were not more than 12 to 15 feet tall but were of better form and more uniform in appearance. Some recently established plots near the five mile post on the Bartica-Potaro road were visited to observe the more or less per- fected technique used to establish P. caribaea on the infertile white sandy soils of worked- out Wallaba forest. The secondary forest is cleared and burnt over prior to planting with locally raised transplants grown from British Honduras seed. Mycorrhiza is believed to be a factor in successful growth and the transplant beds are supplied with mycorrhiza infested mother trees at six-foot intervals; the infection is from the original Trinidad stock. The transplants are six months old and eight to twelve inches tall when planted barerooted. Each tree is dressed with two ounces of superphosphate. A dense ground vegetation, bracken spp. being most prominent, appears quickly after burning. Initially this vegetation provides shade beneficial to the young plants; how- ever, its growth is so rapid that cleaning cannot be long delayed. In February 1958 trees planted 2 months earlier were 18 to 30 inches tall while some planted in July 1956 were 4 to 5 feet tall. The only harmful agent noted was the cutting JANUARY - JUNE 1958 ant (Atta spp.) which defoliates and oiten kills the young pines. TRINIDAD One week was spent in Trinidad studying three forestry projects on that island: The establishment of Pinus caribaea plantations; the growing of teak (Tectona grandis Linn F) in plantations; and the tropical shelter- wood system of silviculture as locally applied. PINUS CARIBAEA The first attempt to establish this pine almost a decade ago met with little success. However, the results obtained since 1952 seem to indicate that for sandy soil of low fertility the technique has been mastered. Nursery practice — Pine nurseries at Co- muto and Brickfield were visited. These nurseries use methods evolved in British Honduras. Concrete germination beds are located under permanent shelters with al- ternate translucent roofing panels. The beds are filled with pure washed sand; the seed is sown broadcast or in rows one inch apart and covered with a thin layer of washed fine gravel Damping-off is virtually non-existent and the seedlings looked extremely healthy. The seeds are sown in November or Decem- ber and transplanted about four weeks later. Seedlings normally develop very long tap rcots, usually without laterals, which may require pruning before transplanting at a 3 by 3-inch spacing in specially prepared beds. The nursery worker’s task has been made less arduous by raising the germination beds to waist height. The transplant beds are made up of soil, sand, and pen manure mixture to give a con- sistency that enables the material to be cut with a machete into 3 x 3 x 3-inch blocks, each block hoiding a single transplant. Trans- plant beds are kept thoroughly weeded and a pine needle mulch is applied. Shade is provided either by a temporary shelter of 39 palm leaves or by a more durable split bam- boo cover which can be rolled up. Seedlings in the transplant beds are usually root pruned at least twice between March and May (8). The planting stock produced is usually in the form of six month old transplants 8 to 10 inches tall. Site preparation-taungya — The recent pine coupes in the Longstretch Reserve were es- tablished in much the same way as were the extensive teak plantations on the island. The larger trees In an area of poor secondary forest are bought and felled by timber mer- chants and charcoal burners are allowed to work over the area in the year preceding the entry of the gardeners. The coupe is burnt over in late April before the gardeners ente7. This probably destroys much of the humus but the increased potash resulting from the burn undoubtedly helps both the trees and the catch-crops. The tree crop is planted in June of the following year, during the rainy season, at a spacing of either 7 x 7 feet or 8 x 7 feet. Before the trees are felled each gardener is allocated an area to culti- vate, rarely more than two acres, for which he pays a nominal rent. The gardener is re- sponsible for felling all trees not cut for tim- ber or charcoal; frequently the gardener is also the timber licensee or charcoal burner. He is limited to the use of certain annuals but he may plant cassava and pigeon peas. Corn, dasheens, and hill rice are other com- mon crops. It appears that some crops are more eifective than others in keeping down the various grasses which compete seriously with the tree crop in their early stage of de- velopment. For the first three years after the gardeners leave an area, weeding is usu- ally done to free the trees from competing grasses. A small plot was noticed in the 1956 coupe where the gardener had been allowed to grow crops for two years instead of the usual one. Trees on this area showed a distinct increase in height growth over the remainder of the coupe. 40 Nine months after planting a number of light demanding tree species were in evidence in the 1957 coupe in addition to the fairly abundant fern, sedge and grass species. The most prominent were melastomaceous species except for Cecropia peltata L. Natural re- generation of C. peltata has been pyolific in both the 1956 and 1957 coupes obviously thriving on the fresh mineral soil after clear- ing and burning. This species alone, because it is so prolific and fast growing, will likely increase weeding costs a great deal on such sandy sites before the pine canopy closes. The cutting ant (Atta. spp.) systematically defoliates the young pines and frequently cause some mortality. The ant nest are treated with a solution of Aldrex but it is difficult to eradicate them entirely Rate of growth — In the Longstretch Re- serve height increment in the first year reaches up to three feet. Where cultivation had been carried on for two years in the 1956 coupe, some of the trees were 15 to 20 feet tall. Height growth in the 1952 Piarco Road plot was most impressive. The tallest trees in this plot were up to 35 feet in height and were 6 to 7 inches in diameter; trees averaged 25 fest tall with d.b.h. of 4 to 5 inches. An adjoining plot one year younger was almost identical. There was a great variety in tree form in all the plots visited. Form varied from the tall spindly type frequently devoid of branches to the very branchy form usually without a definite leading shoot, or with sev- eral vertically growing branch shoots com- peting with the leader. Strange to say, the best formed pines seen were in the 1950 plot in Arena forest where the trees had been suppressed by hardwoods for two years. Three distinct forms are recognizable by their different habits and leaf characters in one-year old plants and were pointed out in ‘tne Brickfield area by the local forester. The irregular whorl forms mentioned were also seen in P. caribaea plots in British Gui- ana and in Jamaica in the closely related P. CARIBBEAN FORESTER occidentalis and in P. patula Schl., & Cham. The same condition is described in P. radiata D. Don., planted in Australia in a paper by Jacobs (8). He suggests that the resting of the terminal bud while the subterminal branch buds are active is due to the con- dition of the buds during the ‘adolescent state’ of the tree. He found that while fa- vorable conditions for growth continue, suc- cessive internodes are produced on the main stem and the main axis of the tree is able to keep ahead of the developing branch whorls. Unfavorable conditions, especially drought, force the growing tip to form a resting bud and it is this that causes most of the unfortunate whorl types and double leaders. Seed bearing — A little variable seed which gave satisfactory seedlings was extracted from cones collected from four-year old trees in the Piarco plots. The flowering season ap- pears to be during December and January. TEAK GROWING The first experimental plantings of teak in Trinidad date from 1913. A definite teak planting programme was drawn up in 1928 and since that time the area planted annu- ally has gradually increased until in 1956 it reached 775 acres. At that time the Forest Department could boast a teak estate of 10,121 acres (11). Some of the best teak in Trinidad has been grown on areas of calcareous clay in- terspersed with sandy loam which cover the low ridges in the south and center of the is- land. Detailed accounts concerning the es- tablishment of those stands can be found in 1941 and 1943 issues of “The Caribbean Forester’? and also in other publications by Lamb (8) (10). The present standard tech- nique uses stump plants produced in nurs- eries located in or near the coupe to be planted. Two such nursery sites were visi- ted. One site being used for the second time produced planting stock much inferior to the other; seedlings were up to three feet JANUARY - JUNE 1958 shorter. For this reason the practice of using a nursery site more than once is usu- ally avoided. Site preparation and establishment is ac- complished by the taungya system much as described under establishment of Pinus cari- baea. A recent development has been the planting of pine in the teak coupe along the ridge tops where the growth of teak has al- ways been found to be poorest. The best stand of teak seen was the 1940 coupe at Brickfield. Initially planted at a 6 x 6 foot spacing there are now, after three thinnings, about 150 trees per acre with an average height of 50 to 55 feet and an aver- age d.b.h. of 11 to 12 inches. The 1955 coupe at Brickfield had suffered widespread damage from the cutting ant which in teak seems to be more selective usually attacking the newly developed leaves at the top of the tree. Fortunately teak seems to be more resistant to depredation than pine and can withstand severe attacks. Brickfield Forest Industries — This is a compact little factory operated by the Forest Department which is kept fully occupied using all the products of thinnings, except possibly some of the first, from teak planta- tions for one purpose or another. Trees to be removed in thinnings are marked by the Forest Department personnel and felled by contrators who buck the ma- terial into specified lengths. The contractor splits the material from the smallest trees into pickets on the site for use in making picket fencing at the factory. The fencing is made in 25-foot lengths in three sizes, namely 2, 4-1/2 and 6 feet high. When completed the fencing is rolled up and treated with a half and half creosote-diese- line mixture using the hot and cold bath process. Larger trees removed in thinnings are sawn using a Gorwood circular gang saw to obtain scantlings in such a way that the thick slab material can be put through a roller feed resaw to produce floor boards. 4] All saleable material is graded to standarize the product and help build up a large and satisfied market. TROPICAL SHELTERWOOD SYSTEM A number of coupes in the Arena Reserve were visited to observe the management oi natural stands under the local technique of the tropical shelterwood system. The local technique was developed in the Arena area and the results are perhaps the most impres- sive aspect of forestry seen in Trinidad. The local application of the shelterwood system was based to a large extent on the activities of the charcoal burners at a time when there was a great demand for that product. -To- day this demand is rapidly diminishing and the effect that this and the generally ex- panding econemy will have on the system has been summed up in a paper by Moore (12). The same paper also describes the application oi the tropical shelterwood sys- tem in Trinidad. Initially timber fellings and fellings by the charcoal burners were regulated so as to leave an exploited compartment with a shel- terwood of dominant trees of marketable species. Intensive tending was carried out up to and including the seventh year with the shelterwood being progressively removed, when necessary, by poisoning. These inten- sive cleanings resulted in high establishment costs and since 1948 the amount of cleaning has been considerably reduced. Another fac- tor which has tended to reduce the amount of cleaning is that some species formerly regarded as weeds now command a ready market. The carefully tended stands show the benefits of such intensive management. The 1940 and 1943 coupes are so uniformly well stocked with trees of excellent form that at first glance they look almost like planted stands. Among the species most successfully re- generated in this way are Tabebuia serratifo- lia (Vahl) Nichols, Didymopanax morototoni (Aubl) Dene & Planch, Carapa guianensis 42 Aubl., Ocotea spp., Byrsonima spicata (Cor) Rich., Sterculia caribaea R. Br., and Termi- nalia obovata (R&P) Stend. It is interesting to note that the studies have shown that there is no apparent relationship between the species in the shelterwood and the species regenerated (11). The inference is that re- generation is from seed already in the ground or that it is brought in by birds and bats which use the shelterwood as a perch. The practice of supplementing natural re- generation by planting has been discontinued since generally enough natural regeneration is obtained. In some areas certain desirable species not present on the site have been planted as a future source. One such species Simarouba amara Aubl., a fast growing spe- cies indigenous to Tobago and Grenada, was planted under a shelterwood in the Arena Reserve in 1944. The shelterwood was re- moved by 1948 and in 1958 the planted trees reached a height of 60 feet and a d.b.h. of 12 to 15 inches. By the end of 1956 Trinidad had almost 20,000 acres of natural and planted regener- ation; this represents 1.7 percent of the total area. An excellent forest road system adds considerably to the forest estate. 'The con- crete achievement in Trinidad should serve as an incentive to other countries in the West Indies. Their task has, however, been made somewhat easier than that in some countries by the preservation of large areas of natural forest and by the much lower elevations and gentler topography available for forestry. LITERATURE 1. Dallimore and Jackson. 1948. A Handbook of Coniferae. 10. if. 12. CARIBBEAN FORESTER Barber, H. D. and Dardean. 1930. Flora D’Haiti. Essig, E. O. 1951. College Entomology. MacMillan. Wellwuod, R. W. The Physical and Mechanical Proper- ties of pinus occidentalis. Carib- bean Forester, Vol. 7, p 207. Harrar and Reid 1942. Retention of creosote oil in wood of pinus occidentalis. Tropi- cal Woods, No. 71. Huckenpshler, B. J. 1957. Preliminary test of methods to kill undesirable tropical trees. Un- pub. Study Plan. Fanshawe, D. B. 1947. Studies of the trees of British Guiana. 11. Greenhart. Tropical woods, No. 92. Lamb, A.F.A. 1956. Exotic forest trees in Trinidad Tobago. Government Printing Of- fice. Jacobs, M. R. Detection of annual stages of growth in the crown of pinus radiata. Com- monwealth Forestry Bureau, Bull. No. 19. Lamb, A.F.A. 1956. Teak. Unpub. Forest Depart- ment. Paper. Forest Department Trinidad & Tobago. 1956. Annual Report. Moore, D. 1957. The effects of an expanding economy on the tropical shelterwood system in Trinidad. Government Printing Office. * at pe = te of =" OPE PE TEM GAG FR ae gee : : oe f. =" ‘ en ’ = y ‘ > fy : S = — . ws \ ELAN | , EAWN \ a rE NEN ‘i \ 3S d ae! INS zs \t é : TAO WWE QW on Ye S NX \y 2 SF 2. NYY, = yg N 5, *~ F* \38 z pa: a \ ‘ 3 a ~ \ : us Ss S ° x \ ‘ f : oe OF AGRICIN Type oe eee e Caribbean Forester ~_ en A : U. S. DEPARTMENT OF AGRICULTURE , FOREST SERVICE Fl TROPICAL FOREST RESEARCH CENTER RIO PIEDRAS, PUERTO RICO “VOLUME 19 NOS. 3 AND 4 JULY - DECEMBER, 1958 Caribbean Forester El “Caribbean Forester’, revista que el Servicio Forestal del Departamento de Agri- cultura de los Estados Unidos comenz6 a pu- blicar en julio de 1938 se distribuye semes- tralmente sin costo alguno y esta dedicada a encauzar la mejor ordenacién de los recursos forestales de la regidn del Caribe. Su propo- sito es estrechar las relaciones que existen entre los cientificos interesados en la Ciencia Forestal y ciencias afines encarandoles con los problemas confrontados, las politicas fo- restales vigentes y el trabajo que se viene haciendo para lograr ese objetivo técnico Se solicita aportaciones de no mas de 20 paginas mecanografiadas. Deben ser someti- das en el lenguaje vernaculo del autor, con el titulo o posiciédn que este ocupa. Es impres- cindible incluir un resumen conciso del estu- dio efectuado. Los articulos deben ser dirigi- dos al Lider, Centro de Investigaciones Fo- restales Tropicales, Rio Piedras, Puerto Rico. Las opiniones expresadas por los autores de los articulos que aparecen en esta revista no coinciden necesariamente con las del Ser- vicio Forestal. Se permite la reproduccién de los articulos siempre que se indique su proce- dencia. e The “Caribbean Forester”, published since July 1938 by the Forest Service, U. S. Depart- ment of Agriculture, is a free semiannual journal devoted to the encouragement of im- proved management of the forest resources of the Caribbean region by keeping students of forestry and allied sciences in touch with the specific problems faced, the policies in effect, and the work being done toward this end throughout the region. Contributions of not more than 20 type- written pages in length are solicited. They should be submitted in the author’s native tongue, and should include the author’s title or position and a short summary. Papers should be sent to the Leader, Tropical Forest Research Center, Rio Piedras, Puerto Rico. Opinions expressed in this journal are not necessarily those of the Forest Service. Any article published may be reproduced provided that reference is made to the original source. Le “Caribbean Forester”, qui a été publié depuis Juliet 1938 par le Service Forestier du Département de I’Agriculture des Etats-Unis, est une revue’ semestriele gratuite, dediée a encourager l’aménagement rationnel des fo- réts de la region caraibe. Son but est d’entre- tenir des relations scientifiques entre ceux qui s'interéssent aux Sciences Forestiéres, ses problemés et ses méthodes les plus récentes, ainsi qu’aux travaux effectués pour réaliser cet. objectif d’amelioration technique. On accept voluntiers des contribution ne dépassant pas 20 pages dactilographiées. Elles doivent étre écrites dans la langue ma- ternelle de l’auteur qui voudra bien préciser son titre ou sa position professionnelle et en les accompagnant d’un résumé de I’étude. Les articles doivent étre addressés au Leader, Tropical Forest Research Center, Rio Pie- dras, Puerto Rico. La revue laisse aux auteurs la responsibi- lité de leurs articles. La reproduction est permise si l’on présice l’origine. *The printing of this publication has been approved by the Director of the Bureau of the Budget (June 26, 1958) VoL. 19 Nos. 3 AND 4 JULY - DECEMBER 1958 The Caribbean Forester Gomer: s S (Gingell: Possibilities of Mexican and Central American Pines in theaWorldeketorestations Projects = S22 = 43 N.T. Mirov and Egon Larsen her Cajaputpaarcerinet loriday 222.) 2 ee 50 Elbert A. Schory, Jr. Indicaciones para la Repoblacion Forestal de las Fincas OYE) J EUUKSNT Oy I ALO eg Ee ee ce 56 José Marrero y Frank H. Wardsworth ihewWitihzationom-Leakin Lrinidad 222022. s 80: Philip Ross - 4 yo — JULY - DECEMBER 1958 Possibilities of Mexican and Central American Pines in the World Reforestation Projects By: N. T. MIROV California Forest and Range Experiment Station 1/ U. S. Forest Service, Berkeley, California, U. S. A. and EGON LARSEN Forest Research Institute Rotorua, New Zealand Pines grow naturally only in the Northern Hemisphere, 2/ but they are also planted rather extensively south of the Equator. The largest pine plantations are located in New Zealand, Australia, Chile, and Union of South Africa. Smaller pine plantations may be found in any South American country. In the future there will be more planting of pines in both hemispheres. At present, Pinus radiata of California is the most popular pine in reforestation of the countries located in Southern Hemisphere. Mexican pines (such as P. patula) are used to a lesser extent, and in Europe they are planted chie‘ly in botan- ical gardens. The purpose of this paper is to call attention of world foresters to the pos- sibilities offered by the Mexican and Central American pines for afforestation purposes. Moreover, as tree-breeding is progressing rapidly in many countries, breeders should be interested in many good qualities of Mexican and Central American pines. In fact, at the Institute of Forest Genetics, of the U. S. Forest Service, near Placeville, California, Mexican Pinus montezuma was successfully crossed with local California P. ponderosa. Mexico and Central America posses more species of pine than any other region of comparable size. The Central American coun- 1/ Maintained at Bekerley, California, by the Forest Service, U. S. Department of Agriculture, in cooperation with the University of California. 2/ Reports that pines occur in Sumatra, south of the Equador are questionable. tries are included in this paper because their pine forests are actually (except Pinus cari- baea of the coast) a continuation of the pine forest of Mexico. Professor Dr. Maximino Martinez, of the Mexican Instituto de Biolo- gia, lists in his monumental work “Los Pinos Mexicanos” (Second Edition, Ediciones Bo- tas, 361 pages, III. 1948) 66 different pines: 39 species and 27 varieties and forms. Dr. Martinez has been very conservative in de- scribing new species; probably in the future more new pines will be discovered in Mexico and in the three Central American republics of Guatemala, Honduras, and Nicaragua. Mexico and Central America offer pines that would suit many diversified reforesta- tion projects. There are high elevation spe- cies, such as Pinus rudis or P. hartwegii that would thrive in temperate climates. There are pines of the warmer localities, such as Pinus pseudostrobus, or P. herrerai; these species grow surprisingly fast. There are real drought- enduring species, such as the pifion pines of northern Mexico. Some of the Mexican and Central American pines have possibilities as ornamental trees. Of outstanding beauty are: Pinus lumholtzi (Pino triste) with its drooping foliage, resembling a horses’s mane, P. pseudostrobus, which is much planted in residential sections of Guatemala City, and P. pinceana of dry gulches in the state of Coahuila. P. pinceana from a distance looks more like a peppertree (Schinus molle) than 44 a pine. Pinus caribaea of British Honduras (Belize) and of the Mosquito Coast of Ni- caragua is an ideal tree to plant in many tropical coastal areas and islands. P. patula has become very popular as an ornamental in California. The value of Mexican pines is generally accepted and many countries are keenly in- terested in obtaining seeds of the more im- portant ones. In the past, when a country wanted to plant authentic seed of a Mexican pine, the procedure was to send a trained forester to Mexico to explore and identify the species and,to arrange for seed collection. Such were Loock’s visit to Mexico in 1947 */ and sporadic collections of some American visi- tors. It appears that it is now time to organize seed collecting in Mexico by more satisfac- tory methods. There can be no doubt that a large scale ceed-collection mission to Mexico is needed. Many countries want seed of Mexican and Central American pines (and Mexican Dou- glas-fir), but the multitude of species and strains within each species and the lack of commercial tree seed merchants in Mexico have so far made delivery impossible. Much time and money will be saved and much disappointment avoided if the large- scale use of Mexican and Central American tree species in world forestry can start on a sound basis. A world-wide comparative trial of species and strains is the obvious approach, but to establish such an experiment with what seed may be procurable from govern- ment or commercial sources in Mexico and Central America is at present quite impos- sible. It would not have the degree of uni- formity that is desirable, and it would re- present only part of this large section of the world. 3/ Loock, E.E.M. The pines of Mexico and British Honduras. Union of South Africa, Dept. of Forestry. Bul. 35, 1950. Early collection are fully discussed in this book. CARIBBEAN FORESTER Where to Collect Mexico and Central America may be di- vided into at least 8 seed-collecting centers (see Fig. 1 and Table 1). These centers are of course, the centers of the most prominent forest regions. Table I shows the most con- venient heaqduarters for each seed collecting center. Most of these places contain offices of local lumberman associations or some competent foresters. The table also shows the most important pines of the regions. For further information, the reader is urged to consult Dr. Martinez’ “Los Pinos Mexicanos.” Ecological Difficulties The many species and the existence of different ecotypes and varieties within each species makes it very difficult to determine what species or strain to collect and where to get it. Even if the forester could decide which species and strain would be the most suitable for his requirements, he would prob- ably find it impossible to obtain the seed. This situation is in many respects com- parable to the one which existed after the first successful introduction of such Ameri- can species as Pseudotsuga menziesii, Pinus contorta and P. ponderosa into Europe and elsewhere. Already at that early stage it was realized that the seed source (provenance) was very important, or in other words, that to a forester the species name was of limite significance without the tag of origin. A tremendous amount of research work has been carried out in many countries since then to determine which species and provenances were the most suitable for any particular locality. Considering the time and the effort spent on this work one might think that the forester by now would have the solution to these problems. On the contrary one finds a great deal of confusion and disagreement on the provenance problem. JULY - DECEMBER 1958 In selecting the most suitable provenance for a given planting site, it is reasonable to look for a region within the natural range of a species that most closely resembles the planting site. Usually only a few factors such as temperature and precipitation are consider- ed, and it is not fully realized that environ- ments cannot be characterized by a few simple standard tests. In fact, it seems very doubtful if the growing conditions of any one locality are to be found in any other part of the world. As a strain or ecotype naturally is a product of the influence of all environment factors, it is not surprising that the result of such a selection usually is desappointing. Without present knowledge of the interrela- tion between plant communities and their environment it is obviously impossible to determine theoretically the most suitable seed source for a given planting site. The only safe way — and undcubtedly the cheapest way in the long run — is to obtain seed samples at regular intervals throughout the natural range of each species and test their growth in the regions where the species are likely to be of importance. The distance between seed collection areas will naturally depend on the topography and climatic conditions in the region. There must be a certain amount of uniformity in an area before one seed lot can be said to be repre- sentative of the forest there. On the other hand, it would hardly be worth the effort to go into too great detail. If a “near-best’”’ provenance (ecotype) can be found, further improvements can be achieved through selec- tive breeding of this material at a far lower cost. The junior author had the opportunity 45 to deal with these problems during a seed cellection tour to the western United States in 1956. The object of the visit was to collect seed samples of the important forest trees of this region for species and provenance trials in New Zealand. Past experience had shown that interior species and provenances were not suitable for New Zealand conditions, so the seed collection work was contined to the region west of the Sierra Nevada-Cascade Mountains divide. The most important spe- cies (Pseudotsuga menziestii, Pinus ponde- rosa, and P. contorta) were sampled at in- tervals of approximately one degree latitude, and for each parallel at regular intervals of altitude, as well as from different aspects. A total of 160 seed samples were obtained during the 6 weeks the collection season lasted (each sample from 5 to 10 trees). Three forestry students from the University of California assisted in the cone picking. All the cones were shipped to a central place for extraction and cleaning of the seed. The work required some 15,000 miles of traveling by car, and the seed cost was about three times the total value of the seeds at cata- logue price. These details are given in order to convey some idea of what can be done. Certain fac- tors — extremely good cooperation from the U. S. Forest Service, an above average cone crop, and a good system of roads in the re- gion — made the work easier than can gen- erally be expected. Yet it seems clear that seed collection in Mexica and Central Amer- ica can be arranged along similar lines. CARIBBEAN FORESTER 46 qaydsiway usbysam au} ul s}sau0} auid a ae a | JO fll] UIaYyNOS ob 00e O02 0 00! ode 001 oO os | Oo! . VOIMSWV TIVYLN3S0 ONV OOIX3W dO SLS3Y¥O04 Y3SIINOO Yy ty 3 Z “iif Wy, ) @DiIXny” 7 Y Y y Uy Yyy Uy Ly yy, Y Y Vy YY cy e y Beene: obuounge + ONW0S « @S0110q YY |O1,0dge@ » onyonyiy) @ JULY - DECEMBER 1958 TABLE 1 — SEED COLLECTING CENTERS OF MEXICO AND OF CENTRAL AMERICA ~l Seed colecting centers Suggested headquarters Pine Species Sonora — Chihuahua Durango — Sinaloa N. E. Desert Rangers (Coahuila, Nuevo Leon, Tamaulipas) Michoacan Jalisco Mexico, D. F. and adjacent states (including parts oi Veracruz) Chiapas Highlands of Central America (Guatemala, Honduras Nicaragua) Caribbean Coast of Nicaragua Honduras and British Honduras (Belize) | Chihuahua City Casas Grandes Pararl | Durango Saltillo, Parras Cd. Victoria Uruapan Morelia Guadalajara Mexico, D.F. San Cristébal (Las Casas) Tuxtla Guatemala, Guat., Tegucigalpa, Honduras, Matagalpa, Nicaragua Puerto Cabezas, Nicaragua Tela, Honduras Belize, B. Honduras mtd ty Wh Ooty trig why . engelmanni, P. arizonica . ayacahuite brachyptera . chihuahuana, P. leiophylla engelmanni, P. arizonica . lumhollzii, P. herrerai . cembroides . greggi, P. arizonica . nelsoni, P. pinceana P. douglasiana, P. lawsoni P. michoacana, P. pringlei P. tenuifolia, P. oocarpa CuG: . patula, P. teocote . rudis, P. hartwegii montezuma, P. leiophylla . ayacahuite montezuma, P. oocarpa . pseudostrobus . ayacahuite tipica . S. chiapensis . oocarpa, P. hondurensis . pseudostrobus . montezuma, P. rudis S. chiapensis ae) . caribaea 48 Local Problems of Seed Collecting In Mexico and Central America It is not an easy task under present con- ditions to get authentic pine seed (or any other forest tree seed) from Mexico and Cen- tral America. One difficulty is the great var- lability in Mexican pines caused, at least some times, by hybridization among different varieties of a complex species like Pinus pseu- dostrobus. Extreme forms in this complex, that is, P. pseudostrobus typica and P. pseu- dostrobus vat. oaxacana are so different that they could well be called different species. Apparently they cross, and the complex in- cludes all sorts of gradations. Moreover, there are indications that some varieties of P. pseu- dostrobus cross with some varieties of P. mon- tezuma. What kind of P. pseudostrobus seed would a customer get if be ordered P. pseu- dostrobus seed from Mexico? Many different kinds of pine seeds could be shipped under this name. Another hazard is the extensive range of some Mexican pines (including the two men- tioned). Pinus oocarpa is perhaps the best example. It grows in its typical form from southern Sonora to the highlands of Nicara- gua. Even if a typical form is specified there is no guarantee that the whole shipment had been collected in the same place. Disaster might result if the shipment were composed of seeds gathered in different localities of its range. Of course, there is the ever-present prob- lem of correct identification of trees. This is not an easy job when cones are harvested in a mixed pine forest composed of five or six different species. The laborer is always tempted to pick as many cones as possible, disregarding their identity. Still other problems arise in collecting and handling the cones. Climbing trees calls for equipment that is not easily available. Seeds have to be extracted at some centrally CARIBBEAN FORESTER located place, and good supervision is essen- tial at an extraction plant to avoid damaging the seed by heat and moisture or mislabeling the seed lots. Furthermore, to collect cones in the forest, one has to have a permit from the local forest authorities. Mexican forest laws are very strict, and a seed collector should familiarize himself with these laws. Then last, but not least, to ship the seed, there are different kinds of permits to be ob- tained, customes rules, quarantine regula- tions, unavoidable delays, etc. All these for- malities are time consuming. Preliminary Studies It appears desirable that, before estab- lishing a permanent seed collecting agency in Mexico-Central America, an expedition be sent to different forest regions of Mexico and Central America for preliminary survey of seed collecting possibilities, and at the same time to collect seed for establishment of prov- enance and species trials in the countries that are interested in these species. This work could not be done by one man, however, and surveying all the important forest regions of Mexico and Central Amer- ica in one season would probably require more than one party. A party should consist of a botanist who is familiar with the Mexi- can pines, and a forester who is familiar with cone collection and seed extraction work. Three or four helpers should be aavilable to climb trees for cones and botanical specimens. After a brief check of the material by the botanist to assure that correct species is being dealt with, material and cones could be shipped to a central place for extraction and cleaning of the seed. The botanical specimens would form an excellent basis for a study of the morphological variation in Mexican and Central American pines. It would also be possible to take wood specimens and ship them to a testing station. As important as it is to have the services of a qualified botanist on such a mission, it JULY - DECEMBER 1958 cannot be strongly enough emphasized that a practical-minded seed collector is essential. Seed collection may appear to be a simple and easy task, but on the scale outlined here it requires careful organization and experi- ence (and a good physique). It is obvious that an international organ- ization would be in the best position to ar- range such an expedition. Permanent Organization The next step, it seems to us, is establish- ment of a permanent seed handling agency. Such an agency should be organized by the FAO branch of the United Nations, but run by the Mexican and Central American de- partments. An international organization would be able to draw experts from all parts of the world. When the agency is organized and well run, sufficient seeds could be col- lected to supply all interested countries. A central office of the agency should be estab- lished, probably in Mexico City, and several branch offices, at least one in each forest region. The central office could organize both seed collection and handle collection of pol- len of forest trees for breeding purposes. If a country needs seeds of pines or any other forest trees, the request should go to the central office, which should then forward the 49 request to an appropriate branch office. If the problem is difficult, a specialist should be sent from the central office to help local seed collectors. Local foresters would be competent to organize cone collection, to supervise the seed extraction, and to certify seeds as to their identity, purity and germination capacity. Yet a great deal of organization work has to be done before a seed collecting agency would function properly. Men are to be trained to climb the trees and gather cones, to dry these, to extract seeds. Time of cone and pollen harvest has to be ascertained for each major species. All these (and many other) activities require a considerable initial expense. But when a seed agency is functioning well, it would be a profitable enterprise. It would give a substantial income to local people, it would provide jobs for many trained Latin American foresters and rangers; and it would be of great benefit to the countries that need seeds of Mexican and Central American pines for reforestation. NOTE—Conference on Pines of Mexico: FAO and the government of Mexico plan to hold a conference for world foresters in Mexi- co during September or October 1960 on the pines of Mexico. This will be right after the 1960 World Forestry Congress to be held in Seattle, Washington, U.S.A. 50 CARIBBEAN FORESTER The Cajaput Tree in Florida By: ELBERT A. SCHORY, SR. Tropical Research Branch Assistant Florida Forest Service HISTORY Melaleuca leucadendron, commonly called Melaleuca now growing in Florida but most Cajaput, Paper Tree, or Punk Tree, was first of them are purely ornamental, resembling introduced to the East Coast of Florida in’ the Callistemon or Bottle Brush, to which 1906 by Dr. John C. Gifford. In 1912 seeds they are closely related. Fig. 1 - Young stand of cajaput showing form and dense cover on wet site. By highway of Estero, Flo- rida. of this species were also imported from Aus- GENERAL CHARACTERISTICS tralia by A. H. Andrews and planted at the japut i timber t hich h Koreshan Unity on the lower West Coast. ie ba deveemenn nme cna wieNCe SBS from the early plantings referred to above There are numerous species of the genus’ until it covers several hundred acres, mostly JULY - DECEMBER 1958 in lower Lee County. The tree is well adapted to the low, wet, sandy soils as shown by the fact that in many places it is actually crowding out the native baldcypress Taxo- dium distichum (L.) Rich. On these sites it grows rapidly and in dense stands develops relatively straight, clear stems. (Fig. 1). Unfortunately cajaput does not confine itself to these areas but also reproduces itself on the adjoining drier sites where it crowds Saag Bees Fig. 2 - Cajaput taking over pine site, (Fig. 2) thus sometimes causing it to be considered a weed tree. While no actual growth studies have been con- out slash pine, ducted, it is evident from casual observation that on these drier and poorer soils the growth is inferior both in size and form. Un- der favorable conditions in its native habitat in Western Australia, the tree is reported to Or 4 reach a height of 80 feet and a diameter of 3 feet. However, in Queensland (Eastern Australia) Swain, reported it as “usually seen as a tree of 40 feet in height and as many inches in girth.”’ Growing as it does under a wide variety of soils and climatic conditions, this variation is not surprising. Most of the available information con- cerning the wood comes from Australia. Swain sets forth the characteristics as iol- Lee County, Florida. lows: “The wood when air dried weighs about 46 pounds per cubic foot, is compact, even, fine, and short grained—pale pinky- brown hue. Tough and firm to cut, the wood has the defect of brittleness, and this defect increases with age’’. Nearly every reference mentions that the wood is quite durable, both in and out of the weather, especially in moist 52 locations. It is evidently also quite resistant to termites. Like many fast growing hardwoods, the timber is inclined to check and warp in sea- soning. Quarter-sawing and seasoning slowly under cover are recommended as preventive measures. There is also the possibility that kiln drying could overcome this characteris- tic. MECHANICAL CHARACTERISTICS Five small logs, the largest having a top TABLE 1 — PERCENT OF CARIBBEAN FORESTER diameter of 8 inches, were sent to the U.S. Forest Product Laboratory at Madison, Wis- consin for standard machine tests. Being small, they were found to be full of small knots and no clear test material was ob- tained from them. Even so, the results were very favorable, being above the average of the native U. S. utility hardwoods and com- paring favorably with furniture woods. Re- sults of the specific tests with two native species included for comparison are shown in Table 1. DEFECT-FREE PIECES Black Av. for 25 Test Cajaput Walnut Sweetgum U.S. Species Planing 60 62 51 61 Shaping 50 34 ah 25 Turning 90 91 86 79 Boring 80 100 92 89 Mortising 70 98 58 70 USES ture, while its color gives it rank as an excellent cabinet timber, and so Wumber is one of the best all-round timbers As might be expected with a wood of this description, it is highly recommended for fur- niture and cabinet making, especially the smaller items and for flooring where short lengths can be utilized advantegeously; the Sawmillers Association of New South Wales, Australia has recommended it for this pur- pose. R. T. Baker, Lecturer on Forestry, Syd- ney University, had this to say: A pale, delicately tinted, light brown wood, one of the finest timbers in the museum. It is hard, yet light in weight, dresses easily, polishes well, has a nice, close grain and even tex- of the Continent; obtainable in fair- sized logs, and could thus be used for bridge decking, boat knees, beams, piles, etc. as it is very dura- ble in the ground and in the water, for which it is especially recom- mended. Having no pronounced sap- wood and being free from borers, it, therefore cuts up with little waste. It is a splendid timber for gun stocks and carvings, the texture giving a sharp arris. In addition to the uses mentioned above, long lengths of clear lumber can be used for almost any purpose from framing to trim in the boat industry. On the other hand, the JULY - DECEMBER 1958 short lengths and odd sizes, including some of the limbs could be used to advantage by the South Florida novelty and souvenir manufacturers. Minor Uses In many localities in South Florida the cajaput has become a favorite tree for land- scaping and for this purpose has much to recommend it. It can be grown on a wide range of soils from high-dry to low-wet and Or vo on saline soils. Planted closely together for windbreaks it withstands hurricanes well; it can be pruned into a hedge or grown in the open. When open grown, it has a tendency to branch. With its distinctive white bark and often twisted limbs it has a rugged beauty. (Fig. 3). These same characteristics recommend it for use in pasture as a windbreak and shade tree. One big advantage in its use heve is that it is not necessary to fence the young Fig. 3 - Typical landscape specimen of caja- put, showing attractive bark and branching habit. Fig. 4 - Natural reproduction of cajaput. Esti- mated age, 5 years. 54 trees as livestock do not ordinarily browse them. Another point in their favor is that they are not readily destroyed by fire. On the other hand, it should be born in mind that there is danger of the tree spreading to areas where it is not wanted and thus become a problem. This is especially true on low, wet ground. The young trees are readily cut into post material and it is rpeorted that in Austra- lia untreated posts stand up well on low, wet ground. This has not been verified in the United States. In an experiment, conducted by the Florida Forest Service, untreated green sapling posts used in fence construc- tion on a dry sand ridge were serviceable after three years. Cajaput oil, a standard pharmaceutical product, has been produced from the leaves but labor costs make commercial production unprofitable. The bark of this species, composed a3 it is of many layers of fine, papery material has had many suggested uses. In Australia the bark, after shredding, is used to stuff mat- tresses and pillows, partly because it is na- turally mildew resistent. A plastics manufac- turer found the bark suitable as a filler. Pulpwood When considering the possibilities of this wood for cellulose and pulpwood production in South Florida there are a number of fac- tors to be taken into consideration: (1) there is no market for material of this kind at present, (2) the supply is very limited, (3) the wood puip produced is not desivable for the manufacture of Kraft papers because, like most hardwoods, the fiber is very short and hence lacks tear strength (4) it is a long haul by rail to the nearest mill. On the other hand, the material is readily available and on moist sites the young trees srow in dense stands of fairly straight, clear poles of a convenient size for handling. This CARIBBEAN FORESTER is perhaps the most attractive feature from the pulwood standpoint. Growing as densely as it does, however, creates a felling problem. Although there is currently no pulpwood market for hardwoods of any kind in Flori- da, there are indications that the future may be brighter. A private report reveals that pulpwood production in the South may be expected to double by 1975. The additional pulpwood to meet the added requirements of the mills is expected to come from three sources in relatively equal amounts: (1) in- creased growth of pine, (2) increased use of waste materials, and (3) increased use of hardwoods. That this trend is already in evidence in some southern mills is indicated by the following statement by Mr. FE. L. Demmon, retired Director of the Southeas- tern Experiment Station of the U. S. Forest Service: The southern pulp industry uses more hardwoods in its processes ev- ery year. For the South as a whole, this ammounted to about 12 percent in 1953. Although lmbiness, tight bark, weight, distribution and varie- ty of species make hardwoods some- what more costly to handle than pine, they offer certain advantages, particularly when _ semi-chemical pulping is used. With this process, one cord of hardwood will produce about a ton of pulp, whereas with the sulphate process an average of 1-3/4 cords of pine is needed per ton of pulp. Improved techniques have been developed for pulping hardwoods, and the use of southern hardwoods for pulp will undoubtedly increase during coming years. There are two mills in the State of Flor- ida that are now producing cellulose, for which use length of fibers is not important. It is understood that one of these plants is basically prepared to utilize hardwoods. When this becomes a reality, there is no ap- JULY - DECEMBER 1958 parent reason why cajaput cannot be used along with the other hardwoods. While some difficulty may be experienced in removing the bark of the cajaput, this can probably be compensated for by selling the bark as a by- product. MARKETS As previously stated, there is no com- mercial market for cajaput in the United States at the present time. This may be due to the limited distribution of the species since the same thing is true in certain sections of its native Australia. However, a developing market may encourage sufficient volume of raw material, and once the wood is produced in commercial quantities it should compete favorably with imported and native species of similar characteristics. CONCLUSIONS Advantages Wood is attractive, machines well, and has some resistance to rot and termites. The tree grows on wet land, is straight and fast growing. It is apparent- ly resistant to fire, disease and browsing. Disadvantages Has possibility of becoming Or [ec | a weed tree. It is small; the wood comes in short pieces; it is short grained: has a tendency to warp and check with sea- soning; and becomes progressively brittle with age. Suggested uses Flooring, trim, furniture, boat building, novelties, field crates, gen- eral construction, landscaping and wind- breaks. The above information will perhaps ap- praise the present status of the cajaput tree in Florida. What the future holds for it, only time will tell. It is asking too much to ex- pect a new species to receive instantaneous universal acceptance, but in this instance there is good reason to believe the species could be a valuable addition to the economy of South Florida. LITERATURE CITED Swain, E. H. F. 1928. The timbers and forest products of Queensland. Queensland Forest Service. 500 pp. Baker, R. T. 1919. The hardwoods oi Austra- lia and their economics. Technological Museum of Tech. Ed. New South Wales. Series 23. 522 pp. 56 CARIBBZAN FORESTER Indicaciones para la Repoblacion Forestal de las Fincas de Puerto Rico Por: JOSE MARRERO Y FRANK H. WADSWORTH Centro de Investigaciones Forestales Tropicales RIO PIEDRAS, PUERTO RICO El Publico de la isla, incluyendo gran parte de los técnicos agricolas. tienen una idea muy vaga sobre nuestro problema fores- tal o si en realidad existe tal problema. Se han preparado informes describiendo en de- talle lo que se considera un serio problema de conservacién de recursos naturales, pero dichos informes son conocidos solamente por un estrecho circulo de técnicos. Este articu- lo tiene por objeto presentar informacion para uso dei publico basado en los informes arriba mencionados y en datos de los archivos del Centro de Investigaciones Forestales Tropica- les del Servicio Forestal Federal y orientada a contestar las siguientes interrogaciones: 1. gPorqué es indispensable aumentar el area forestal de la isla? iw) . gCuales serian las areas a repoblarse y las probables maneras de enfrentar el problema? 3. gCuales son las especies que hasta la fecha se han encontrado més adapta- das a los distintos terrenos forestales de la isla y en qué época es preferible hacer las plantaciones? La contestacién a la ultima interrogacio6n es puramente de cardcter técnico y pocas veces se ha presentado en una forma orga- nizada a los técnicos relacionados con las plantaciones forestales tales como oficiales de los servicios forestales, agentes agricolas, ma- estros de agricultura vocacional y otras per- sonas directamente relacionadas con el tra- 1/ A Comprehensive Agricultural Prezgram for Puerto Rico, N. Koening, Departamento de Agricultura Federa!, pag. 105. bajo de repoblacién forestal. La infermacién que se presenta es producto de reconocimien- tos, estudios e investigaciones realizado3 du- rante varios ahos y esperamos que supla la informacion necesitada para la mejor ejecu- cién de las labores de repoblacién. AREAS FORESTALES Y SUS PROPOSITOS Los dos millones y pico de cuerdas que encierra la isla de Puerto Rico estuvieron casi totalmente cubiertas por bosques. Se sabe que la poblacién indigena apenas hizo mella en los bosques. Sin embargo, desde que se inicié la colonizacion de la isla los bosques han sido gradualmente y repetidamente des- truidos para dedicar las tierras a cultivos agricolas, para pastoreo, para localizacién de pueblos, ciudades y caminos, de manera que en la actualidad quedan menos de 590,000 cuerdas cubiertas de bosques y malezas e in- cluyendo las arboledas de café. Se calcula que de los bosques destruidos, sdlo se utiliz6 un 20 por ciento 1/_ y el resto se quem6 y desperdicié. Excepto unas 90,000 cuerdas in- cluidas en los bosques ptblicos, insulares y federales, los cuales incluyen bosques de va- lor, el balance incluye bosques de poco valor productivo. El desmonte de terrenos de valor perma- nente para agricultura se justifica. Sin em- bargo, existe mucho terreno de escaso valor agricola y que por su naturaleza debe con- servarse bajo arboleda, que en la actualidad esta deforestado y no rinde gran provecho. Las cosechas de cultivo limpio, muchas de las cuales son de gran rendimiento, no pue- den producirse continuamente en terrenos JULY - DECEMBER 1958 muy inclinados debido al peligro de la pér- dida de suelo por erosion. Debido a la topografia montafosa de la isla se estima que el terreno accidentado sobre 50 por ciento de pendiente (casi todos sobre el 60 por ciento) llega a unas 691,000 cuerdas, 2/. Otras areas de uso limitado que no pueden o no deben dedicarse a cultivo limpio por otras razones como la de ser roco- sas, muy htimedas, muy secas o estériles y por haber disponibles otras tierras mds apro- piadas para la produccidn de cosechas agri- colas y para satisfacer nuestras necesidades Negaran a unas 368,000 cuerdas. 3/ Suman- do estas dos categorias se ha llegado a la conclusién de que mas de un millon de cuer- das o casi la mitad de las tierras de la isla no se prestan para cultivos limpios Las cosechas llamadas protectoras o sea que no requieren la labranza o cultivo del suelo serian las llamadas a cultivarse en esta mitad de la isla que no se presta para culti- vos limpios. Dichas cosechas protectoras in- cluyen el caf, el forraje y los bosques. Las dos primeras cosechas donde pueden culti- varse en la actualidad aparentemente pueden dar mayor rendimiento que la produccién de madera, pero son mas exigentes en sus re- querimientos. Los estudios ya mencionados indican que cel mill6n aproximado de cuer- das que no se prestan a cultivos limpios unas 520,000 cuerdas aproximadamente podrian dedicarse a la produccién de forraje y de café. El] resto como de 540,000 cuerdas que no se necesitan o no se prestan para otros cultivos, podrian dedicarse a bosques sin de- trimento alguno para la produccién de otras cosechas y bajo un plan correcto de uso de la tierra. Hoy casi todo el terreno que no se presta a otros cultivos se usa mayormente 2/ Décimoctavo Informe Anual del Centro de Investigaciones Forestales Trepicales, 1958. Este inferme en parte esta basado sobre datos publicados y no publicados de la Division de Bos- ques, Pesca y Vida Silvestre, Autoridad de las Fuentes Fluviales ae Junta de Planificacion del Estado Libre Asociado de Puerto ico. 3/ Décimoctavo Informe Anual del Centro de Investigaciones Forestales Tropicales, Servicio Forestal del Departamento de Agricultura de los Estados Unidos. Or ~) para un pastoreo extensivo en detrimiento de la conservaci6n de los suelos y del agua. Conservacion de las Aguas No debemos pensar exclusivamente a base de la produccién de productos tangibles de valor monetario como las cosechas, ganado y maderas. El] bosque por su influencia sobre el clima y la conservacién de las aguas contri- buye al bienestar de toda la poblacién de una manera dificil de valorar en términos de pesos y centavos. En este sentido es de mas valor que ningun otro uso posible de la tierra. El Décimoctavo Informe Anual del Cen- tro de Investigaciones Forestales Tropicales discute el problema de las aguas en los si- guientes términos: “Nuestra escasez de agua no se debe generalmente a la falta de lluvia. De los 13,000,000 acrepiés recibidos cada afio en Puerto Rico solo 1,230,000, 0 menos del 10 por ciento, estan disponibles como flujo cons- tante de los rios. Parte de la diferencia se pierde por evaporaciOn, parte es usada por la vegetacién (ventajoso dondequiera que se producen productos de valor) pero casi la mitad corre sobre la superficie del terreno durante las liuvias, causando’ erosién en los suelos y corriendo rapidamente hacia el mar o a lo largo de los rios. Aunque en estos grandes proyectos de riego se usan anual- mente 210,000 acrepiés y aunque tenemos 19 plantas de fuerza hidroeléctrica, no hay la menor duda de que en la actualidad estamos dandole uso efective a menos de la mitad del agua que recibimos. Nuestro verdadero problema es conservar el agua que recibimos hasta que se le pueda dar un uso efectivo. Los aguaceros torrencia- les nos proveen con lluvia mas rapidamente de io que es absorbida por el terreno, de ma- nera que corre cuesta abajo sobre la super- ficie. Esta escorrentia es especialmente fuerte en areas donde el suelo desnudo recibe direc- tamente el impacto completo de la lluvia, se torna fangosa y obstruye los poros del suelo, 58 o donde la superficie del suelo esta ya com- pacta por el intenso pastoreo. Esto sobrecar- ga los rios, desborda nuestras represas, el agua corre hacia el mar frecuentemente cau- sando inundaciones en su curso. A esta agua, que viene de repente e inesperadamente en grandes cantidades y cargada de sedimento, es virtualmente imposible darle uso antes de gue se pierda. Si se va a almacenar para usarse mas tarde, como durante las sequias, serian necesarios inmensos embalses artificia- les. Nuestros embalses, costosos e impresio- nantes como son, solamente tienen capacidad como para 400,000 acrepiés de agua cada ano. Ademas, continuamente pierden su_ valiosa capacidad de almacenamiento debido al sedi- mento, que arrastrado por las aguas de esco- rrentia se deposita en su fondo. La mejor forma de conservar nuestras aguas es alma- cenando mas de ellas en ese embalse natural gue es el suelo. E] agua que penetra el suelo, distinta de aquella que corre por la superfi- cie hacia el mar, necesariamente no se pier- de ni causa erosién. Mientras esta cerca de la superficie esta disponible para ser absorbi- da por las raices de las plantas. A mayor pro- fundidad se filtra poco a poco hacia manan- tiales naturales o esta disponible para sacarse de los pozos, en ambos casos clara y accesible tanto durante periodos de sequia como llu- viosos. Esta es en realidad agua util. Su al- macenamiento solo exige el mantenimiento de una cubierta porosa y receptiva en la super- ficie del terreno. Esta cubierta puede mante- nerse mejor por medio de una capa de vege- tacién continua y densa sobre una capa de hojarasca directamente sobre el terreno. De todas las cosechas el bosque es el mejor que satisface estos requisitos. El sitio para conservar nuestra agua es en las montafias, que reciben lluvias intensas y donde a causa de laderas inclinadas la es- correntia es mds probable, y donde se le pue- de dar mayor variedad de usos al agua al- macenada debido 2 su elevacién. Las areas 4/ Estadisticas de Comercio Extranjero, Negociado de Econo- mia y Estadisticas, Junta de Planificacion de Puerto Rico, 1957. CARIBBEAN FORESTER que producen mas agua casi coinciden con aquellas areas, ya definidas, donde una cu- bierta vegetal es necesaria para _proteger también el suelo.” Produccion de Madera Aquellos terrenos donde el tnico interés sea la conservacion de las aguas, de la vida silvestre 0 meramente conservar el ambiente forestal, no requieren que se establezca en ellos plantaciones forestales. Si ya poseen malezas éstas seguirdn creciendo con solo evi- tar por completo el pastoreo y el cultivo. La conservacion de las aguas y la vida silvestre se logra en poco tiempo dejando crecer la maleza aun sin sembrar Arboles, y lo que es muy importante, no requiere desembolso al- guno excepto para establecer cercas para la proteccion contra el ganado. Sin embargo, la economia de la isla requiere que aquellos te- rrenos que puedan producir productos fores- tales lo hagan, para lo cual en muchos casos es necesario recurrir a la siembra. El informe arriba mencionado considera que no mas del cinco por ciento de la super- ficie de la isla esta cubierta por bosques ma- derables. El resto de los bosques contiene pocas especies de arboles por lo general con- sideradas valiosas, y casi ningun arbol gran- de. Los arboles que ahora se cortan general- mente son usados y desperdiciados porque no se aprecia por completo el valor de su made- ra. Solamente una pequefia parte de la pro- cGuccién de nuestros bosques se utiliza en parte debido a que los costos a que se obtie- nen dichos productos resultan muy altos de- bido a extraccién deficiente, aserrado pobre, secado inadecuado y falta de facilidades de mercadeo. No hay duda de que es necesario produ- cir mds madera si se puede hacer adecuada y econoémicamente. La isla import6d en el ano 1957 productos forestales por valor de $39,300,000 4/ equivalentes a una importa- cién per capita de $17.04. Esto incluye tales _articulos como madera, “plywood”, cajoneria, JULY - DECEMBER 1958 mangos de herramientas, puertas y ventanas, postes, pilotes, productos de papel y otros. Producimos todos los postes de cerca y toda la lefia y carb6n consumidos que son los pro- ductos de mas volumen pero menos valiosos. Los principales productos maderables alcan- zan un volumen de cerca de 100,000,000 pies tablares, ademas de grandes cantidades de muebles fabricados, papel y otros productos. Una de las principales interrogaciones es la cantidad de madera que podriamos produ- El informe mencionado ofrece datos grarse dentro de las Areas criticas que 59 cir. El informe del Centro de Investigaciones, ya mencionado, especifica que deben dedicar- se a la produccién de madera toda aquella parte de las 500,000 cuerdas de terreno pro- piamente forestal donde sea econdmicamente factible y de resultar insuficiente esta drea podrian producirse dentro del milloén de acres de terreno que no permite cultivo limpio o en cualesquiera otras tierras donde la produc- cidn de madera rinda mas que las otras co- sechas. de los productos forestales que podrian lo- requieren proteccién forestal. TABLA 1 — EXTENSION Y PROBABLE LOCALIZACION DE LOS TERRENOS FORESTALES FROPIOS PARA LA PRODUCCION DE MADERA Region de Areas mas propias dentro de Productos terrenos forestales los terrenos forestales miles de cuerdas Papel Suelos lateriticos 28 Suelos lé6mico-arenosos 9 Muebles Zona caliza himeda 56 Suelos arcillosos profundos 4? Postes para 9 cercas Manglares Arboles de Suelos ]6mico-arenosos al Navidad profundos Cabos de Suelos Il6micos poco 8 herramientas profundos Pilotes y Suelos l6mico-arenosos 17 postes profundos Cajoneria Suelos l6micos poco 12 profundos Total 182 60 Sitios de Recreo A pesar de que los paisajes de las mon- tafias de la isla son de gran belleza escénica, estan desprovistos de arboles. Su repoblacién forestal sin duda aumentaria considerable- mente su atractivo como sitio de recreo. El éxito y la demanda de tales centros de re- creo pueden apreciarse por el gran éxito de la famosa Area recreativa de la Mina en el Yunque en el Bosque de Luquillo, visitada durante el afio 1958 por 169,000 personas, lo que trajo una inversion de unos $417,000 por los visitantes lo cual pone una _ valoracién minima de $9,500 por cuerda en el area re- creativa sin incluir, desde luego, las entradas por les servicios que se puedan proporcionar al visitante. El Centro ha calculado que se necesitarian unas 12 areas, cada una con una area de 46 cuerdas, a lo cual se le calcula un valor equivalente en dinero a cerca de $850,000 anuales para servir a la poblacion actual y a los turistas. En el futuro las fa- cilidades recreativas habrian de ser aumen- tadas para servir a una poblacién mayor de residentes y turistas. REPOBLACION DE LA FINCA Una de las mayores interrogaciones es quién y de qué manera se realizara la repo- blacién del Area que por carecer de arboleda habria que repoblar artificialmente. Ya hemos expuesto que los bosques publicos incluyen en total unas 90,000 cuerdas las cuales estan practicamente cubiertas por bosques, Por lo tanto, el grueso del area a repoblar se en- cuentra en las fincas particulares. La zona cafetalera la cual incluye una area considerable que se calcula en por lo menos 160,000 cuerdas, ofrece el mejor ejem- plo de como se podrian repoblar otras 4reas. La gran obra de repoblacién con Arboles de sombra y de café ze hizo debido al incentivo econoémico que ha representado el cultivo del café. Comprendemos que el 4rea total a re- poblar es ain mas extensa y que habria pro- blemas de mano de obra que no existieron al CARIBBEAN FORESTER establecer las plantaciones de café. Kl incentivo para la reforestacién seria de dos tipos: 1. Ganancia que se derivaria por el culti- vo de cosechas forestales. 2. Incentivos monetarios putblicos como contribucion para la repoblacién y pa- ra la proteccién de las plantaciones por dafios ocasionados por el ganado, etc. Actualmente las siembras de especies fo- restales se hacen de especies que el agricul- tor necesita en la explotacién de la finca ta- les como varas y postes en aquelias zonas donde no se consiguen Arboles naturales es- pontaneos en la finca. Naturalmente, estas siembras se hacen en pequefia escala sola- mente para satisfacer las necesidades de la finca. Cuando existan especies comerciales cuyo cultivo pueda hacerse remunerativamen- te en rotaciones cortas, posiblemente para uso industrial, entonces se podria generalizar la siembra de arboles en una escala de tal mag- nitud que afecte zonas extensas de la isla. El desarrollo industrial debe proveer mercado para absorber dicha materia prima producida en la isla. Actualmente existe en Ponce una indus- tria que absorbe gran parte de la produccién de madera de yagrumo hembra de la zona cafetalera y hay otras industrias que podrian utilizar mayores cantidades de madera si se produce a precios convenientes. La fabrica- cidn de papel y cart6n a base de bagazo de cafia, para lo cual pronto operara una {abri- ca en Arecibo, requiere el uso de pasta de madera de pino para mezclar con el bagazo. Hay ademas otras industrias ya establecidas que podrian usar maderas producidas en la finca. Mientras que en las cosechas tradicio- nales de cana, café y tabaco existe exceso de produccién mundial y por lo tanto, mercados deprimidos, en los productos forestales hay una mejor perspectiva por estar la produc- cion y el consumo mejor balanceados. En relacién a los incentivos monetarios JULY - DECEMBER 1958 que paga el gobierno, se calcula que en la actualidad el agricultor recibe como la mitad de los gastos en que incurre en la siembra y en cercar las plantaciones. Durante el ano 1958 ciento veinte terratenientes recibieron pagos de compensacion por practicas foresta- les por un total de $5770. Otro de los incen- tivos incluye demostraciones y asesoramien- to técnico y exencién contributiva por la Ley Num. 438 del ano 1934. Las principales cosechas agricolas reciben fuertes subsidios y ayuda gubernamental como en el caso del café, tabaco, y cana de azucar. Es l6gico que para competir con otras cosechas sera necesario que el gobierno sub- vencione fuertemente el cultivo de plantacio- nes forestales, especialmente durante la etapa inicial del desenvolvimiento de !as_ planta- ciones. E] gobierno tiene un marcado interés en promover la produccién de materia prima que sirva de base para su extenso programa industrial e indudablemente daria toda la ayuda posible. HISTORIA DE LA DISTRIBUCION DE ARBOLES A TERRATENIENTES El programa de distribucién de arboles a terratenientes, a otras agencias del gobierno, a amas de casa y a asociaciones interesadas principid en el afio 1921 y se ha continuado hasta ahora. La cantidad distribuida aumen- t6 gradualmente hasta un total de dos mi- llones anuales la que se ha reducido en los ultimos afios hasta cerca de la mitad de esta cantidad. En total se calcula que se ha dis- tribuido al ptiblico unos 65 millones de arbo- litos, suficientes para repoblar unas 94,000 cuerdas. Sin embargo, un inventario reciente demuestra que el area de plantaciones es in- significante y no excede del 3 por ciento del area que se suponia sembrada. Parte de esta discrepancia se debe a que algunos de los 4ar- boles han sido cortados para utilizarse. Sin embargo, gran parte de la diferencia se ex- plica solamente por el fracaso de las siembras debido a tales causas como (a) seleccién im- 61 propia del sitio a sembrar; (b) tiempo poco favorable; (c) arboles entregados pero nunca sembrados y (d) proteccién inadecuada de los arboles contra Ja competencia de los yer- bajos, del pastoreo del ganado, destruccién intencional, etc., todo lo cual es el resultado de la falta de supervision de las plantaciones después de establecidas. Sin duda alguna éste ha sido un programa costoso, especifica- mente si se consideran los resultados obteni- dos. El valor de les arboles solamente pasa de $300,000 sin contar los gastos de trans- porte, gastos generales, etc. todo lo cual hace subir el costo considerablemente. Para evitar la repeticién de tales resul- tados se organizO un programa llamado Pro- grama Cooperativo de Manejo Forestal en la Divisi6n de Bosques, Pesca y Vida Silvestre del Departamento de Agricultura y Comer- cio, que dispone de personal de campo que supervisa el trabajo en las fincas y decide cuales agricultores pueden acogerse al progra- ma, cantidad y especie de arboles a sembrar y organiza y supervisa la distribucion de los Arboles. Este programa durante el afio 1958, su tercer afio de existencia, distribuy6 427,000 Arboles con una supervivencia de sobre 85 por ciento, un gran adelanto sobre el progra- ma anterior de distribucién sin supervision. Principiando con una 4rea que incluia cinco municipalidades, el programa cubre en ja actualidad doce municipalidades y seguira extendiéndose gradualmente segin lo ameri- ten las circunstancias. Se ha demostrado que existe gran interés entre los terratenientes por establecer plantaciones forestales y que se pueden lograr buenas plantaciones en un programa bien organizado que supervise so- bre el terreno la labor de reforestacién. La demanda por arboles continia en aumento como resultado de todos los aspectos del pro- grama de repoblacién incluyendo las fases educativas, la mejor supervision en la finca, atractivo de los incentivos y mejor organiza- cién de la distribucién de los arboles. Tal demanda ha sido dramatizada en la celebra- cién del centenario del nacimiento de Munoz 62 Rivera por medio de un programa de siembra de arboles de no menos de un millon de 4r- boles. Un aumento en el uso industrial de arboles cosechados en Puerto Rico sin duda alguna requeriria que se multiplicara el nu- mero de Arboles a sembrarse. Todo ésto hace vislumbrar un aumento gradual o quizas mo- mentaneo en el trabajo de repoblacion en las fincas. ADAPTABILIDAD DE LAS ESPECIES FORESTALES A LOS DISTINTOS SITIOS Uno de los puntos donde es mas deseable ofrecer informacion es sobre las distintas es- pecies que crecen mejor y son mas producti- vas y en qué sitio de la isla deben sembrarse preferiblemente. También falta informacion precisa sobre la época del aho mas apropiada para la siembra en cada localidad. En pri- mer punto llamamos adaptabilidad de espe- cies a las distintas zonas. Existen datos sobre la adaptabilidad de gran ntimero de especies pero presentaremos datos preferiblemente de las especies que estan siendo distribuidas de los viveros del gobierno. Si el namero de estas especies distribuidas aumentara habria que enmendar la lista de acuerdo. Las especies que crecen natural o espontaneamente en los distintos sitios y que no estan incluidas en esta lista, logicamente no se consideran por- que su presencia espontanea en un sitio de- muestra que se dan bien aunque en algunos sitios crecen mejor que en otros. Se puede decir que la adaptabilidad de la especie al sitio es la clave del éxito, es decir, si la especie esta bien adaptada al am- biente, mayormente al clima y al suelo, el éxito esta asegurado a menos que interven- gan cataclismos o sucesos tales como incen- dio, danos por el hombre o animales y ataques por insectos y enfermedades que destruyan la planta. En todos los paises se cometen errores en querer adaptar especies a sitios poco propicios, lo cual a menudo es la razon por el fracaso de programas de repoblacion en distintas escalas desde la pequefia siem- CARIBBEAN FORESTER bra en una finca particular hasta los ambi- ciosos programas en escala nacional con la consiguiente pérdida en dinero y en entu- siasmo. La mayor parte de las especies introdu- cidas que tienen éxito son especies muy adap- tables o sea que soportan gran diversidad de condiciones, aun condiciones adversas. Bue- nos ejemplos son casuarina, cassia de Siam, cassia amarilla, caoba, guama _ venezolano, saman y otras. Otras especies sin embargo, se dan bien centro de un limite mas estrecho de condiciones donde pueden ser muy pro- metedoras, por ejemplo, en Puerto Rico el eucalipto crece muy bien en las mayores ele- vaciones en un clima lluvioso y mas fresco pero cerca de la costa crece por un tiempo y luego languidece. De la misma manera en sitios secos y adversos algunas especies como por ejemplo la caoba de las Antillas se da muy bien al igual que un ntmero reducido de especies, pero gran parte de las especies de ambiantes mas favorecidos al sembrarse en estos sitios adversos si sobreviven crecen poco saludables y claramente fuera de sitio. No debe confundirse la sobrevivencia du- rante un periodo después de la siembra, con la adaptabilidad. Son cosas distintas. La so- brevivencia es el resultado directo de la siembra y de los distintos factores de la siembra tales como reaccién de la especie, tipo de siembra (si a raiz desnuda o con pi- l6n), cantidad de lluvia al tiempo de la siem- bra, cuidado y método de sembrar, precau- ciones, etc. La adaptabilidad de la planta es su reaccion después de establecida a !o3 factores de clima y suelo que se explican a continuacion. Por lo tanto, una planta pue- de estar perfectamente adaptada al medio, por ejemplo, un arbusto de café que sembra- do en un ambiente favorable, digamos como en Utuado y Jayuya, sucumbe al trasplante. En caso contrario bien sea por su habilidad de trasplantar bien y por otras circunstancias favorables, una planta no adaptada al medio puede sobrevivir ciento por ciento y luego gradualmente desaparecer por falta de ajuste JULY - DECEMBER 1958 al ambiente, mostrando asi su falta de adap- tacion. A veces la condicién del suelo es un fac- tor determinante en la adaptabilidad. Los suelos arcillosos en las zonas muy htmedas y mas altas de las montafias, por ejemplo, sufren mucho en su condicién fisica y quizas aun en su composicién quimica al desmon- tarse y dedicarse al cultivo y al pastare irracional y se convierten temporeramente en lo que llamamos suelos degradados. Sin em- bargo, el roble nativo coloniza tales suelos y al sembrarse se da con gran lozania, y es capaz de competir ventajosamente con la maleza y yerbajos que invaden dichos suelos. Otras especies mds exigentes al sembrarse en tales condiciones desaparecen al poco tiempo en parte al no poder desarrollar con la loza- nia y rapidez necesarias para competir con los yerbajos. En Puerto Rico como en todos sitios, hemos sufrido las consecuencias de la falta de informacién y la siembra de muchas es- pecies “fuera de sitio” ha sido una de las principales razones por el fracaso de muchas siembras. Los terrenos forestales publicos, donde fué necesario, han sido repoblados en toda su extensiOn y actualmente existen unos cuantos miles de cuerdas de plantaciones. Naturalmente, en la realizacion de esta labor se acumularon datos 5/ los cuales sumados a los que obtuvieron al examinar plantacio- nes en unas 300 fincas particulares en toda la isla, han proporcionado datos de los cua- les hemos derivado las recomendaciones gue siguen. Desde luego, habia la necesidad de pre- parar estos datos, extensos de por si, en una forma breve y esquematica. Se han prepara- do lo que hemos llamado tablas de adapta- bilidad dando una lista de especies adapta- das a distintas regiones de clima y suelos. 5/ Forest Planting in the Caribbean National Forest, Past Ex- Perience as a Guide to the Future, José Marrero, Caribbean Forester, Vol. 9, No. 2, April 1948. Results of Forest Planting in the Insular Forests of Puerto Rico, José Marrero, Caribbean Forester, Vol. 11, No. 3, July 1950. Gradualmente estos datos se han simplifica- do y Ultimamente han sido combinados con datos de lluvia para dar ademas la época mas propicia para sembrar de acuerdo con el pro- medio de lluvia para la zona. Hemos encon- trado que los factores mas influyentes en determinar la adaptabilidad bajo nuestras condiciones son los siguientes: (1) clma, (2) suelos, (3) topografia, (4) declive, (5) orientacién y (6) exposicion. Naturalmente, no todos estos factores tienen la misma influencia. Unos son mas efectivos que otros y algunos no ha sido po- sible incluirlos en la tabla por no prestarse e ello. Sin embargo, nos proponemos discu- tirlos individualmente para explicar el efecto relativo de cada uno. Los dos factores mas importantes del clima o sea la lluvia y la temperatura, no afectan la adaptabilidad de las especies ai mismo grado. Siendo nuestro clima tropical y nuestra extensién territorial limitada, las variaciones en temperatura son relativamen- te de poca importancia y las que hay se de- ben mayormente a la diferencia en elevaci6n entre el nivel del mar y los cuatro mil y pico de pies que es nuestra mayor elevacién. Como en el trdpico al ascender 300 pies de eleva- cién la temperatura baja 1°F, la diferencia total entre el nivel del mar y los 3500 pies, el limite de Jas plantaciones forestales, seria aproximadamente 12°F lo cual no aiecta mu- cho la vegetacién ya que aun en las elevacio- nes mas altas la temperatura no es lo sufi- cientemente baja para producir heladas. Sin embargo, cualquier diferencia que hubiere se consideraria ya que existe una categoria aparte para la zona sobre los 2200 pies de elevacion. El factor lluvia es de mucha importan- cia por que existe una gran variaciOn entre los sitios mas aridos con menos de 30 pulga- das de lluvia anualmente en promedio y los mas lluviosos con un promedio anual de 180 pulgadas. Los sitios mds secos sufren de se- quias mas prolongadas e intensas. Basados 64 mayormente en la precipitacién se ha dividi- do la isla en tres grandes zonas a saber: (a) costa himeda que recibe entre 60 y 80 pul- gadas anualmente; (b) costa seca que recibe entre 30 a 60 pulgadas y (c) la montajfia, todo el terreno hacia el centro y sobre el contorno de los 500 pies de elevaci6n. En cuanto a los suelos se ha reconocido que la profundidad es de gran importancia en determinar la adaptabilidad y se han es- tablecido dos categorias: suelos poco profun- dos y suelos profundos como subdivisiones de las zonas geograficas arriba mencionadas. Los suelos profundos se consideran aquellos donde existe una profundidad de 18 pulgadas o mas entre la superficie y la roca madre e incluyen los suelos pesados en las zonas mas hamedas de la Cordillera Central, de la Sie- rra de Cayey y en la mayor parte de las montanas de Luquillo. Los suelos menos pro- fundos incluyen la mayor parte de las ver- tientes este y sur de la Cordillera Central y las vertientes oeste y sur de la Sierra de Ca- yey. En la costa los terrenos poco profun- dos son derivados de la roca caliza. Bajo ca- da uno de los grandes grupos de suelos se ofrecen las series de suelos mas importantes lo cual ayuda grandemente a la localizacién de los suelos. KE] factor topografia es uno de los de mayor importancia y como tal se presenta en la tabla. Se considera que la topografia es el factor aislado (fuera del clima) de ma- yor influencia sobre la adaptabilidad de es- pecies en los terrenos accidentados de las montanas. Las condiciones ambientales son mas fa- vorables en las depresiones y en los valles y menos favorables hacia la cima o las cum- bres o sea mas favorables en la ladera c6én- cava que en la ladera convexa. Se han sepa- rado entonces dos sitios diferentes o sea la ladera coéncava o valle y la ladera convexa o cimas y cerros. En muchos casos se ofrece un sitio intermedio entre estos dos que con- siste en la ladera que une estos detalles to- CARIBBEAN FORESTER pograficos y se incluye sencillamente como ladera. (Fig. 1). El drenaje es un factor de menor impor- tancia que la profundidad en esta clasifica- ci6n aunque puede serlo en las zonas mas lluviosas donde las areas planas y de poco declive aparentemente sufren de drenaje po- bre. En la tabla de adaptabilidad la tnica distincién a este respecto se hizo entre los suelos moderadamente a bien drenados don- de se realizan la mayor parte de las planta- ciones y los suelos pobremente drenados in- cluyendo los pantanos donde las plantaciones son muy limitadas. Kl uso a que se ha sometido la tierra in- fluye mucho sobre las especies que pueden adaptarse. Los terrenos forestales especial- mente los terrenos en las localidades mas llu- viosas se deterioran rapidamente al desmon- tarse si se dedican al cultivo intenso o al pas- tareo. Los efectos de la modificacién del suelo debido al uso puede afectar el desarrollo de los arboles, por lo menos temporeramente, tanto o mas como las condiciones fisicas o quimicas inherentes del suelo. Por ejemplo, en los suelos pesados en las areas mas Iluvio- sas en las elevaciones mas altas de las mon- tafias el éxito de la plantacién parece tener una relacién mas directa con el uso a que se ha sometido el terreno que ningtn otro fac- tor, aun mas que otros factores como la to- pografia que se han encontrado ser mas im- portantes en las demas zonas. Expresado brevemente, los suelos de las montafias se de- precian con el uso y a mayor uso menos fa- vorables son las condiciones, lo que reduce el numero de especies que pueden adaptarse. Por razones obvias el factor uso aunque importante es muy variable y completo para incluirse en la tabla de adaptabilidad y es algo que solamente se puede determinar so- bre el terreno en cada caso en que hubiere que determinar la adaptabilidad de la especie. El declive tiene algtin efecto en que los terrenos con declive tienen mayor drenaje lo que afecta la retencioén del agua. Por lo tan- JULY - DECEMBER 1958 to, existe una interrelacidn con drenaje, por lo que en localidades que reciben una preci- pitacién muy alta los arboles crecen mejor en los terrenos inclinados donde el exceso de agua se pierde, en preferencia a los sitios de poco declive que conservan un exceso de hu- medad. En localidades que sufren por sequia, por el contrario, los sitios muy accidentados Sewers F 2 ai Fig. 1 - el valle del Rio Toro Negro cerca de Ciales. Sa eee Una vista panoramica del Interior Montanoso Huamedo 65 cia en los lugares mas secos y expuestos y se nota la influencia sobre la vegetacién en si- tios que reciben como unas 70 pulgadas de lluvia anualmente o menos. Los sitios que dan o estan orientados al este y sur estan expuestos a los vientos que soplan persisten- temente de esa direccién y ademas estan mas expuestos al sol, lo que causa desecacion de- See ee a eee (Zona No. 6) mostrando ; El tepe del cerro poblado de arboles a !a izquier- da de ia foto, al igual que los cerros y las laderas al fondo, pertenecen al Sitio No. 6a. El va- lle y las laderas protegidas que lo circundan pertenecen al Sitio No. 6b. Ambos terrenos, los lomices poco profundos y los_arcilloses profundos estan representados. a veces sufren por falta de humedad mas que los sitios de menos inclinacién. Igualmente los sitios accidentados sufren del mismo modo por erosidn de los suelos. El factor declive, sin embargo, no esta considerado en la tabla porque no es facil establecer relaciones direc- tas entre distintos declives y adaptabilidad con la base que se obtuvo para este trabajo. La orientacién del lugar es de importan- bido a una mayor evaporacién. Por tanto, en sitios secos se nota una vegetacién mas exhu- berante en las laderas orientadas al norte y al oeste y las plantaciones también desarro- llan mejor y con mayor supervivencia. Este factor se ha introducido en la tabla de adap- tabilidad en las zonas montafiosas mas 4ridas. La exposicién se refiere a la cantidad de luz y sombra recibida. La mayor parte de las 66 plantaciones tienen una mejor supervivencia y desarrollan mejor durante los primeros anos bajo cierto grado de sombra. La sombra provee un ambiente mas favorable al arboli- to por la mayor uniformidad en la humedad y temperatura que le provee, ademas porque inhibe el crecimiento de bejucos y yerbajos. También los suelos bajo arboleda conservan condiciones fisicas y quimicas mucho mas fa- vorables que los suelos a la intemperie, los cuales generalmente han estado expuestos al CARIBBEAN FORESTER proceso de degeneraciOn antes descrito. Se- gun desarrollan los arboles necesitan mayor cantidad de luz aunque en ésto existe gran variacion entre muy exigentes hasta poco exigentes. No se trat6 de clasificar las espe- cies de acuerdo con este factor por no existir los datos correspondientes. La tabla siguiente muestra una lista de especies forestales adaptadas con sus usos y de interés actualmente para el programa fo- restal en las fincas. TABLA 2— LISTA DE ESPECIES ADAPTADAS Y SUS USOS PROPIA : as | | Sombra a | ilo largo de. | caminos y i PARA Postes cercas y | y Cercos | para rom-| Sombra | Sombra Nembre Vulgar Nombre Cientifico madera] vivos | pevientos. | ganado café Acacia amarilla Albizzia lebbeck (L.) Benth, x = x. x = Almacigo Bursera simaruba (L.) Sarg. = = - — Bambu Bambusa sp. 7° = x i Bucare Erythrina glauca Willd. a x a = ie Bucare enano Erythrina berteorana Urban =a x = rs ns Bucayo Erythrina poeppigiana (Walp.) O.F. Cook — xX -- = a Caoba hondureha Swietenia macrophylla King x ~ D4 = Cassia de Siam Cassia siamea Lam. x - x a Casuarina Casuarina equisetifolia L. x i x —- Ciruela del pais Spondias purpurea L. a x << tae = Emajagutilla Thespesia populnea (L.) Soland. — vy: X = = Eucalipto Eucalyptus robusta J. E. Smith 2S x Be pe Eucalyptus kirtoniana F. Muell. X x a ca Gliricidia Gliricidia sepium (Jacq.) Steud. x “ = ~ x Cuba Guaba del pais Inga Vera Willd. x = = = Guama venezolano Inga quaternata Poepp. & Endl. en = eT Jagiley Ficus laevigata Vahl. cane X Ras Jobo Spondias mombin L, x a ae a Mamey Mammea americana L. 2s = in os Maria Calophyllum brasiliense Camb. a ‘ A Pterocarpus Pterocarpus indicus Willd. x = a ag Pterocarpus marsupium Roxb. x “ a Ss Roble Tabebuia heterophylla (D.C.) Britton x x x a eat Saman Fithecellobium saman (Jacq.) xX = a Teca Tectona grandis L. xX = JULY - DECEMBER 1958 SITIOS PARA LAS DIFERENTES ESPECIES FORESTALES De acuerdo con los datos ofrecidos de an- temano en Puerto Rico se han reconocido tres regiones principales y siete zonas de sig- nificacion a la adaptabilidad y productividad de especies forestales. Muchas de éstas se han subdividido en otras categorias debido a di- ferencias en la topografia o en el drenaje, re- sultando en la organizacion siguiente. Estas zonas se describen a continuacién incluyendo listas de especies adaptadas a sembrar en ellas. Los bosques y las malezas naturales generalmente contienen otras especies, mu- chas de las cuales aun cuando no han dado buenos resultados al plantarse, son de valor y deben conservarse en vez de destruirlas para sustituirlas por arboles sembrados. Las especies subrayadas son las que se distribu- yen desde los viveros de la Division de Bos- ques, Pesca y Vida Silvestre del Departa- mento de Agricultura y Comercio. COSTA HUMEDA Se incluye todo el terreno de 500 pies o menos de elevacion a lo largo de la costa oes- te, norte y este, desde el norte de la munici- palidad de San German en el suroeste si- guiendo a lo largo de la costa norte hasta el Rio Patillas en el sureste e incluyendo los valles interiores y toda la zona caliza del norte (aqui se alcanzan elevaciones hasta de 1000 pies o mas). ZONA No. 1 — Terrenos poco Profundos de la Costa Humeda Series de suelos: Mucara, Tanam4, Colinas, Soller, Sabana, Naranjito, Yunes, y otras series similares. Sitio No. 1a - Incluye mayormente el tope de los mogotes calizos Especies: maria, roble, casuarina, almacigo, jagiiey Sitio No. 1b - Laderas expuestas a los mo- gotes (debido a condiciones un poco mas 67 favorables se presta a un mayor numero de especies que el Sitio 1a) Especies: maria, roble, casuarina, jagiiey, almacigo, gliricidia, mamey, cassia de Siam Sitio No. Ic - Laderas protegidas y abras (valles) Especies: caoba hondurena, maria, teca, casuarina, gliricidia, jagiiey, bucare ena- no, almacigo, jobo, ciruela del pais, cassia de Siam, mamey, pterocarpus, bambi, bucayo ZONA No. 2 — Suelos Profundos de la Costa Humeda Suelos moderadamente a bien drenados - series: Bayamon, Lares, Moca, Coto, Ma- tanzas, Vega Alta, Camagiiey, Santa Clara, Dominguito, Toa, Estacién, Rio Piedras, Torres, Via, Arenas de la costa, Sabana Seca, Vega Alta, Islote, Mtcara, Juncos, Sabana, Daguao y otras series similares. Sitio No. 2a - Cerros Especies: maria, roble, casuarina, cassia de Siam, almacigo, jagiiey Sitio No. 2b. - Laderas Especies: maria, roble, casuarina, glirici- dia, bucare enano, almdacigo, jagiiey, jobo, ciruela del pais, cassia de Siam, mamey, pterocarpus, bambu, bucayo Sitio No. 2c - Llanuras y aluviones Especies: teca, caoba hondurefia, casuari- na, maria, jagiiey, bucare enano, alméa- cigo, jobo, ciruela del pais, cassia de Siam, emajagiiilla, mamey, gliricida, ro- ble, pterocarpus, samdn, bucare, bambi, bucayo Suelos mal drenados - series: Josefa, Irure- na, Palmas Altas, Yabucoa, Pifones, Cérce- ga, Coloso, Fortuna, suelos orgdnicos y tur- bas y otras series similares Sitio No. 2d - Pantanos manglares de la costa y Especies: casuarina, emajagiiilla (crecen bien en los bordes de los manglares) 68 bucare 1/ (crece espontaneamente en pantanos de agua dulce). Muchas de las especies del sitio anterior crecen bien aqui dependiendo del drenaje. COSTA SECA Todo terreno a 500 pies o menos de ele- vacion en la costa sur y en las laderas al sur de la Cordillera principiando en el valle del Rio Guanajibo hacia el suroeste y luego a !o largo de la costa hasta el Rio Patillas en el este. ZONA No. 3 — Suelos Poco Profundos de la Costa Sur Series de suelos - Aguilita, Ensenada, Lajas, San German, Jacana y otras series similares Sitio No. 3a - Cerros y laderas expuestas Especie: Almacigo Sitio No. 3b - Laderas protegidas y vailes Especie: Casuarina, Cassia Amarilla 3/, gliri- Fig. 2 - Vista representativa de los Suelos Profundos de la Costa Seca (Zona No. 4) Sitio No. 4a. el que sin embargo, no esta considera- do zona forestal por su tepografia Ilana y calidad del suelo, que lo ha- ce muy deseable para la agricultura. El bosque abierto centiene mayor- mente arbeles de almacigo cerca de Salinas. 1/ bucare — Erythrina glauca 2/ La caoba dominicana crece bien y esta muy adaptada a estos pero no se -recomienda su siembra debido a que esta siendo afectada seriamente por una enfermedad muy seria. CARIBBEAN FORESTER cida, almdcigo, Jagiiey, Casia de Siam. ZONA No. 4 Suelos Profundos de la Casta Seca Suelos adecuadamente bien drenados - se- ries: San Anton, Machete, Jauca, Meros, Vives, Altura, Coamo, Fraternidad, Fe, San- ta Isabel, Amelia, Paso Seco y otras series similares Sitio No. 4a. - Llanuras y aluviones Kspecies: samdan, casuarina, cassia amari- lla, caoba Honduras, teca, gliricidia, al- macigo, iagiiey, cassia de Siam, emaja- guilla 2/ Suelos con drenaje imperfecto - series: Gua- nica, Vayas, Aguirre, Reparada, Ursula y sue- los organicos y turba. Existe poca informa- cidn en cuanto a la adaptabilidad de especiees utiles. La casuasina crece cuando el area no se inunda muy a menudo. La emajagiiilla to- lera sitios de drenaje pobre. Muchas de las especies del sitio anterior crecen aqui depen- diendo del drenaje. (Fig. 2). 3/ La cassia amarilla sufre del ataque de una enfermedad que mata los arboles. Su futuro depende en gran parte del curso ce esta enfermedad. JULY - DECEMBER 1958 INTERIOR MONTANOSO Todo el terreno sobre los 590 pies de ele- vaciOn (exceptuando la zona caliza hiameda en la costa norte) y dividido mayormente en dos subregiones incluyendo las montafa3 ai sur y al suroeste de la Cordillera Central que reciben menos de 60 pulgadas de lluvia anual- mente, y las montafias mds himedas en el resto del interior montafioso. ZONA No. 5 — Laderas Secas en el Interior Montanoso Series de suelo - Rosario, Descalabrado, Jacana, Guayama, Mucara y otras series similares Sitio No. 5a - Cerros y laderas con orien- tacion este y sur Sitio muy dificil debido a los efectos de la sequia y de la exposicién. Debe esti- mularse la regeneraci6n del monte natu- ral. Si es necesario hacer plantaciones maria y roble estan entre las mejores es- pecies. Almacigo se propaga bien por medio de esquejes. Sitio No. 5b - Laderas protegidas y valles Especies: Teca, caoba Honduras, casuari- na, samdn, maria, roble, bucare enano, jobo, gliricidia, jagiiey, almacigo, ciruela del pais, cassia de Siam, mamey, cassia amarilla, guama venezolano, bambu, bu- or) ery ~~ cayo (Fig. 3). ZONA No. 6 — Interior Montanoso Himedo a Menos de 2200 pies de Elevacion Series de suelo - Utuado, Panduras, Caya- gua, Nipe, Catalina, Alonso, Cialitos, Mu- cara, Picachos, Naranjito, Sabana y otras series similares. Sitio No. 6a - Cerros y laderas expuesta; Especies: Eucalipto, roble, casuarina, ma- ria, bucare enano, jobo, ciruela del pais, gliricidia, jagiiey, mamey, guaba del pais, guamd venezolano, bambi S:tio No. 6b - Laderas protegidas y valles Especies: Maria, caoba Honduras, casuari- na, teca, eucalipto, bucare enano, jobo, Fig, 3 - Ladera de suelos- loémicos poco profundos al sur de la Cordillera Cen- tral mirando hacia Coamo. Es representativa de la Zo- na Ne. 5 - Laderas Secas en Interior Montanoso. La foto ineluye mayormente el Sitio No. 5a. En la base de esta ladera se encuen- tra el Sitio No. 5b en la iadera protegida pero ha- cia la izquierda fuera de lo encerrado por esta foto. gliricidia, ciruela del pais, guamd vene- zolano, jagiiey, roble, cassia de Siam. mamey, guaba del pais, (Fig. 4). ZONA No. 7 - Interior Montanoso muy Humedo sobre los 2200 pies de Elevacion Series de suelo - Alonso, Los Guineos, Ca- talina, Cialitos, Mucara y otras series simi- lares Los suelos son mas plasticos y pesados que en las elevaciones mas bajas e incluyen la zona mas arriba de la zona de café. La de- gradacion del suelo se hace muy evidente poco después de los desmontes y el suelo arcilloso es entonces propio solamente para 70 las especies mas acomodaticias como el eu- calipto y el roble. Sitio No. 7a - Cerros y laderas expuestas Especies: Eucalipto, roble, bucare enano, jagiiey, guaba del pais, guamd venezolano Sitio No. 7b - Laderas protegidas y valles Especies: Guaraguao, eucalipto, bucare enano, jagiiey, roble, guaba del pais, CARIBBEAN FORESTER TABLA 3 — LOCALIZACION DE LAS ZONAS DE SIEMBRA POR BARRIOS Y MUNICIPALIDADES MUNICIPIO Y BARRIO ZONA ADJUNTAS Garzas, Tanama, Guilarte, y sobre Fig. 4 - Utuado pertenecientes a la Zona No. 6 - Intericr Montanoso Htimedo a menos de 2200 pies de elevacion. Laderas de suelos arenosos l6mico-profundos sobre el embalse de Caonillas en La mayor parte del area ilustrada por esta foto cae dentro del Sitio No. 6a. El fondo del pequeno valle a la derech2 cae dentro del Sitio No. 6b. guamd venezolano, bambu La principal dificultad que ha tenido el personal de campo en la interpretacion de la tabla de adaptabilidad ha sido en poder lo- calizar las areas respectivas dentro de las dis- tintas siete zonas en que se ha dividido la isla. Para obtener la zona se consulta direc- tamente la tabla a continuacién y entonces se buscan las especies que le corresponden al sitio y a la zona en particular usando la tabla de adaptabilidad. 2,200 pies de elevacién en Guaya- bo Dulce Barrios restantes ............... 6 a ee AGUADA Sobre 500 pies de elevacion en Atalaya‘ y Cerro: Gordo .2. ..3....: ~6 Barrios testantesus ac te nace bo ‘AGUADILLA Caimital Bajo, Victoria, y suelos poco profundos en Camaseyes y JULY - DECEMBER 1958 Arenales Barrios restantes ............-... 6 OOO 0 OO Out co DO ic Orn O1GRS AGUAS BUENAS AIBONITO ANASCO Playa, Afasco Abajo, Afiasco Arri- ba, Rio Cafias, Carreras, Espino, Cidra y bajo 500 pies de eleva- cién en Hatillo, Pinales, Caracol, Quebrada Larga, Ovejas y Marias IBarrmioserestantecmencecesei cineca ARECIBO Esperanza, Hato Viejo, Rio Arri- ba y suelos poco profundos en Ga- rrochales, Hato Arriba, Muiraflo- res, Sabana Hoyos, Dominguito y Arrozal IBATTIOS sTeStANLES |.) sessions) suenst stolen s © ARROYO Sobre 500 pies de elevacién en SVCAUITG le ep eit ce oP ns nee ane ors cere eke Barrios restantes c: y-ca2 © aera « BARCELONETA Suelos poco profundos en Garro- chales, Florida Adentro y Florida NMUCT AME Ere oe ree oan sacs eels oi Barniosprestantesmarnx rick ase BARRANQUITAS BAYAMON Nuevo, Dajaos, Santa Olaya y GuaracuaopArribay sacciaseic cee IBarriossrestantesertseie areca CABS ROJO Boquer6én, Pedernales, Llanos Cos- ta, Llanos Tuna y suelos poco pro- fundos en Monte Grande ........ iBarriosprestantesmercs - cr etree cre) CAGUAS San Salvador, Beatriz y sobre 500 pies de elevacién en Tomas de Castro, Borinquen y Cafiaboncito IBALhiossrestanbLesm encase. oak wy) CAMUY Suelos poco profundos en Piedra Gorda, Abra Honda, Santiago y IPUCTLOSMR ese es acu oreko eree IBALTIOS TEStanbes, sie 3 css cnet enone CAROLINA Barrazas, Cerro Gordo, Carruzos WoC CdrOs fs ckns cae tass oa a sere Barrios restantes:....-...+..s..- CATANO CAYEY Sobre 2,200 pies de elevacion en Farallon Barrios) restamtes: .o..-2-.6s-+-..- CEIBA Sobre 500 pies de elevacién en Rio Abajo IBATTIOSPLEStANEES weer sree tes cae aifele, eo jel ere e568 ,e'-0 a; (67 6, “e: -0116: 0) 0 CIALES Hato Viejo y suelos poco pro‘un- dos en Cordillera y Fronton .... Suelos profundos en Cordillera y Frontén y bajo 500 pies de eleva- Clonmene esas: yedaeuas, sae seas Cialitos, Pozas, sobre 500 pies de elevaci6n en Pesas y Jaguas y ba- jo 2,200 pies de elevacién en Toro Negro Sobre 2,200 pies de elevacién en Toro Negro CEIDRA COAMO Los Llanos y San Ildefonso y bajo 500 pies de elevacion en Cuy6on, Palmarejo, Santa Catalina y Pasto Sobre 2,000 pies de elevacién en Pulguillas, Hayales y Pasto...... Beta aoe) Iach|RebnRes: ne wenn Ge ea oon COMERIO COROZAL Suelos poco profundos en Abras .. Cibuco, bajo 500 pies de eleva- 72 cidn en Palmarejo y suelos mas profundos en Abras ............. Barrios: restantes. . ioe) 74 cién en Santo Domingo y Quebra- dae Ceibar & cacud eas selene Barreal, Jaguas y bajo 2,200 pies de elevaci6n en Rucio .......... Sobre 2,200 pies de elevacion en RU CIOs careers wera seem ane eee ie PONCE Magueyes Urbano, Portugués Ur- bano, Canas Magueyes y suelos poco profundos en Coto Laurel y Sabanetas y suelos poco profundos bajo 500 pies de elevacion en Por- CUPIGS 3 hue ewer cidas Oe Cele as Tibes, Machuelo Arriba, Marue- no, Quebrada Limon, Monte Llano y sobre 500 pies de elevacién en Portugués y Real’ 2.2.4 2502. coe San Patricio, Guaraguao, Mara- guez y bajo 2,200 pies de eleva- Cloul-el: “AMON: © a. cls tks o hee Sobre 2,200 pies de elevacién en ANOU -ahwenhiantcaatuekits sie Barrios restantées =. 25 sec ow wenn QUEBRADILLAS Suelos poco profundos en Cacao, San Antonio, Guajataca, Charcas Vip SATUE) OSE. ave eer isnt Barrios restantes ............6:- RINCON Sobre 500 pies de elevacion en Jaguey voAtalaya.: «<<. «5 on oes IBarniOs LEStAN LCS. yn. este stentless RIO GRANDE Guzman Abajo, Herrera, Zarzal, Ciénaga Baja y bajo 500 pies de elevacién en Jiménez y Mameyes Ell avpieeiaePotacdee hs dn ara eee ae Sobre 500 pies de elevacién en Jiménez y Mameyes II pero bajo 2,200 pies de elevaciOn .......... Barrios mestantes: 225-66 eshers RIO PIEDRAS Sobre 500 pies de elevacién en y Quebrada Arenas y Cupey Alto 6 Barrios restantes ............... CARIBBEAN FORESTER Suelos profundos en Rayo, Susta y Machuchal oo5 te: baci s.cy ccm 4 Nantana y Labonuco ...4 2.5.0.2 5 Barrios restantes ............... 3 SALINAS Aguirre, Lapa, Rio Jueyes y bajo 500 pies de elevacién en Quebrada NWieCU as? acre cm eR eee 4 Barriosirestantes: 2.250 4. 3 SAN GERMAN Cotui, Ancones, Tuna, Guama y suelos poco profundos en Maresta, Minillas, Retiro, Sabana Eneas, Duey Bajo, Hoconuco Bajo, Saba- na Grande Abajo y bajo 500 pies de elevacion en Cain Alto ...... 3 Cain Bajo y suelos profundos en Sabana Eneas, Maresta, Minillas, Retiro, Duey Bajo, Hoconuco Ba- jo y Sabana Grande Abajo ...... 4 ROsatios Bajo: anes occ eaeeene 2 Barrios restantes.....2.% @....2 054 5 SAN JUAN 2 SAN LORENZO Espino y sobre 500 pies de eleva- cion en Hato Quemados, Quebrada Honda, Cerro Gordo y Quebrada ATCNAS: 22es cen ee eee 6 SAN SEBASTIAN Suelos pocos profundos en Jun- cal, Magos, Eneas, Guajataca, Aibonito, Cibao, Robles, Salto, Hoya Mala, Hato Arriba, Guate- mala, Cidral y Piedras Blancas .. 1 Barrios restantes 2 2.2.00 5 kee 2 SANTA ISABEL Suelos poco profundos en Descala- bradon ys Jatican 2) aikei asec ene 3 Barrios restantes .............4. 4 TOA ALTA Suelos profundos en Galateo, Pi- fas, Contorno y Mucarabones .... 2 JULY - DECEMBER 1958 Barrios restantes 2. acess. ce i TOA BAJA Suelos poco profundos en Cande- IETS eee on eae S 1 IBarniosenestanbesi em seiner: 2 TRUJILLO ALTO @uevaseye DOs) b0caSHee ee 2 iBarrioserestantesmascceecace ee cles 1 UTUADO Angeles, Caguana, Rio Abajo, Santa Rosa: Suelos poco profundos Sucelossprotundosesy-s. eee] 2 Barrios erestaltesmeisen ae ssc ce |): 6 VEGA ALTA Suelos poco profundos en Espino- sa, Bajura, Maricao, Candelaria, Mavilla y Cienegueta Banriosarestantesm-rr acces ete 2 VEGA BAJA Suelos poco profundos en Rio Abajo, Pugnado Afuera, Rio Arri- ba, Almirante Norte, Almirante Sur, Quebrada Arenas y Pugnado Adentro IBaLnioserestanbtese. --eiciss oe 1-02) 2 VILLALBA Bajo 500 pies de elevacién en Hato Puerco Abajo y Villalba Abajo Caonillas Abajo, Caonillas Arri- ba, sobre 500 pies de elevacién en Hato Puerco Abajo y Villalba Abajo y bajo 1,500 pies de eleva- cién en Hato Puerco Arriba ...... 5 Sobre 1,500 pies de elevacién en Hato Puerco Arriba y bajo 2,000 pies de elevacion en Villalba Arri- lSE Mave NEG le oe bo Soo noo oo Oee 6 IBALEIOSELESUALLLCS EE EI eee 1 YABUCOA Camino Nuevo, Juan Martin, Ya- bucoa, Playa, Limones, Camino ~l Or Nuevo, Aguacate y bajo 500 pies de elevaci6n en Calabazas y Tejas 2 IBATTIOSBTCSEANUCS os cicrec ss eis sce eos 6 YAUCO Quebradas, Almacigo Alto, Susta Alta, suelos poco profundos en Almacigo Bajo, Caimito, Diego Hernandez, Jacana, Barina y Su- sua Baja, y bajo 500 pies de ele- Vacion en, Algarraqno 2. see. ua. 3 Sierra Alta, Duey, Vegas, Collo- res, y sobre 500 pies de elevacion CnwAlParrovOr comes ois areas ean 5 Aguas Blancas, Naranjo, Ran- cheras, Rio Prieto, Frailes y Ru- PLES eae ee eee tities Sekt een ce a cies Raiee ae 6 BATEIOS# TESLAN LES or =eaciaisz- es hawks os 4 EPOCA DE SIEMBRA La experiencia demuestra que la siembra de arboles a raiz desnuda solo tiene éxito du- rante épocas de lluvia y especialmetne si el suelo continua humedo durante algtin tiempo después de la siembra hasta que el arbolito esté establecido. En las zonas mas aridas co- mo en las nimeros 3, 4 y 5 la siembra a raiz desnuda es arriesgada a menos. que se puedan regar las plantitas hasta que estén estable- cidas, algo que resultara costoso. En estas zonas, especialmente en las mas secas, es aconsejable sembrar las plantas con un pilon de tierra si se interesa obtener una sobrevivencia aceptable. Muchas de las es- pecies durante afios muy favorables sobrevi- ven sembradas a raiz desnuda pero en anos normales no pueden resistir los periodos de sequia. Ejemplos son la caoba dominicana, la cassia de siam, la casuarina, el samdan, etc. Las especies que se siembran directamente por semilla tales como la maria y la cassia pueden establecerse a pesar de la sequia, lo mismo que las especies que se propagan ve- getativamente como el jobo, la glicirida, el alinacigo, jagiiey, aunque a veces el porcen- taze de esquejes prendidos no es alto. En la Tabla 4 hemos asumido que la me- 76 jor sobrevivencia se obtiene cuando la lluvia promedio durante el mes de siembra alcanza o excede 6 pulgadas de lluvia y no baja de 4 pulgadas, tanto en el mes anterior al de la La ta- bla siguiente se prepar6 marcando en un ma- pa y relacionando los datos de lluvia durante 40 afios. Se hicier6n excepciones a esta regla siembra como en el mes que le sigue. TABLA 4 — MESES PROPICIOS PARA LA CARIBBEAN FORESTER en la costa sur donde ningtin mes Ilena los requisitos pero sin embargo, se siembra con éxito en algunos anos durante los meses mas lluviososos. También los meses de enero y marzo se excluyeron porque estan restringidos a tan pocas areas, que la produccién de ma- terial de vivero no se justifica especificamente para estos meses. SIEMBRA DE ARSOLES EN PUERTO RICO MES DE MUNICIPIO Y BARRIO SIEMBRA ADJUNTAS 5-11 AGUADA Atalaya, Cerro Gordo, Laguna, Naranjo, Mamey, Marias, Gua- nabano y Mal Paso .;....2...:. Barrios restantes' -.... 366.465 AGUADILLA AGUAS BUENAS AIBONITO ANASCO ARECIBO Garrochales, Hato Abajo, Cam- halache, Islote, Santana y Factor, Hato Arriba, Miraflores, Sabana Hoyos, Domingo Ruiz, Arenalejos Ne Panaiaoec 1s prema Carreras, Dominguito y Arrozal Esperanza, Hato Viejo y Rio Arri- PiBiseat cceetetn trsespnte aces tate emt arora ARROYO Palmas y Gudcimas ........... Barrios restantes ...........-. BARCELONETA Florida Adentro .............. Florida vAtuera: