= : Circular 36 © | PLL PN O'S" NCA TUR Ae Ao Sie Re Yate Ue Re Ey In Cooperation With University of Illinois - College of Agriculture - Agricultural Experiment Station and Extension Service in Agriculture and Home Economics — : 4 sr , 5 ey * ze ere Nacucal Mi story Uys | STAVES “Ole AVEIEIHNIOUNS Dwight H. Green, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Frank G. Thompson, Director Planting and Care of Shade Crees JES DANS THE LIBRARY OF THE NOV 5 1947 UNIVERSITY OF ILLINOIS Printed by Authority of the State of Illinois NATURAL HISTORY SURVEY DIVISION Harlow B. Mills, Chief _ Circular 36 (Third Printing, With Additions) Urbana September 1947 S2A hs SOPs Tesi NeOates Dwicutr H. Green, Governor DEPARTMENT OF REGISTRATION AND ce Frank G. Tuompson, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Frank G. THompson, Chairman Cart G. Harriman, Ph.D., Biology L. H. Tirrany, Ph.D., Forestry L. R. Howson, B.S.C.E., C.E., Engineering GeorceE D. Stropparp, Ph.D., President of the University of Illinois Wa ter H. Newnouse, Ph.D., Geology Rocer Apams, Ph.D., D.Sc. , Chemistry NATURAL HISTORY SURVEY DIVISION Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF Hartow B. Mitts, Ph.D., Chief Bessie B. HENDERSON, MESS Section of Economic Entomology GeorceE C. Decker, Ph.D., Entomologist and Head J. H. Biccer, M.S., Entomologist L. L. Encuitsu, Ph.D., Entomologist C. J. We1nman, Ph.D., Entomologist S. C. Cuanpter, B.S., Associate Entomolo- gist James W. Appre, M.S., mologist Wiis N. Bruce, B.S., Assistant Ento- mologist Joun M. Wricut, B.A., mologist H. B. Perry, M.A., Associate in Entomolo- gy Extension Georce F. Lupvix, M.A., Special Re- search Assistant Joun E. Porter, M.S., Laboratory Assistant Associate Ento- Assistant Ento- Section of Faunistic Surveys and Insect Identifications H. H. Ross, Ph.D., Systematic Entomolo- gist and Head Mitton W. Sanperson, Ph.D., Taxonomist B. D. Burks, Ph.D., Associate Taxonomist Lewis J. STANNARD, JR., B.S., Assistant Taxonomist Puy tuis A. BEAvEr, Technical Assistant Puiztie W. Smitn, Laboratory Assistant Associate Section of Aquatic Biology GeorceE W. Bennett, Ph.D., Biologist and Head P. G. BarnickxoL, M.A., Aquatic Biologist D. F. Hansen, Ph.D., Assistant Aquatic Biologist EvizapetH B. Cuase, Ph.D., Assistant Jacos H. Lemn, Field Assistant Daniet Avery, Field Assistant Aquatic Technica / CONSULTANTS IN HERPETOLOGY: issiee to the Chief Section of Forestry Wititet N. Wanve t, M.F., Forester @ Head Lawson B. Cutver, B.S., Forestry Extension Associate Section of Game Research and Manag: ment Ratpu E. Yeatrter, Ph.D., Game Speci Frank C. BeEttrose, B.S., Associate Gan Specialist Haro.p C. Hanson, M.S., dssistant Gaw Specialist Dean H. Ecke, Field Assistant Section of Applied Botany and Plant Pathology Leo R. Teuon, Ph.D., Botanist and He J. Cepric Carter, Ph.D., Plant Pathologs J. L. Forssperc, M.S., Associate Pla Pathologist G. H. Borewer, M.S., thologist Rosert A. Evers, M.S Assistant Plant P, » Assistant Botanw Section of Publications and Public Re lations James S. Ayars, B.S., Technical Editor an Head Rospert E. HesseE_tscHwerpt, B.A., Assis ant Technical Photographer Technical Library MarGueERITE Stmmons, M.A., M.S., Tee nical Librarian Cooperative Wildlife Research C. C. Swears, M.F., Project Leader Pau J. Moores, B.S., Project Leader Georce C. Artuur, B.S., Project Leader A. B. Cowan, B.S.F., Assistant Proje Leader Howarp K. Grorp, Ph.D., Director of the Museum, Chicag Academy of Sciences; Citrrorp H. Pope, B.S., Curator of "Amphibians and Reptiles, Chicaj Natural Histor “y Museum: This paper is a contribution from the Section of Forestry. (88087—10M—6 -47) — —e Pip iG Con. 4 Contents PAP OTES NACE Hse AD Y Tree ih Relea Le ea ey sol ge 2 ina smGne reese TO? USE 72... aces tnd SMe ee ne Ce ae ee Mead 2 STACI CON ety chins hy si gc, Seri aag esate Ge oe Cal OP tay ee ORL ee Ss 3 SOURCESHO ha bl amin is COCK sete ten as he ee ee 4 SOG GLE LELET LT ORES, ITH oe Maen aia mde ae We RIAN he Neer RA AGNES pyre ds A 4 OralitvaorslantingsS tock e = at) koh eee eee eee ee 5 Peano nade Gres on Fo lidte teed tie tee theese Bee a Sas Be ee Meek 5 Wh enmto mb antes 30 oct Pee ge eas, alr in tees tees ae Aten hy al Rg 5 EVO WACOM LATIEM hk 35s Se A Sth eecuae. et a Pee aE een edhe Ree ha aes 6 Sarcrotevewlvarianted Drees). 8 pga ee a ek ee 7 RP STSELTVETY Re DN yr va soy te sy A hee RC lw PE Rc go eer ake 7 NE tapi ean) raein sesh .go 2 oc) tects e, esta eee ede OE eee. 8 VEO TMOEEOUCCUIONC sous «kt eo ees ae ae es oie 19 AVVAU CORT Dene F aot As Saline Cie SRL Welk ETS pe RES bey a Mie Saher tate Nn 1) CaremeimOlders NLGes so) ile Oe eo ne ce ca eee MeN ote 11 TUITE Cone es sie en eee tee ORO Naa Se nee ol oe 11 Carezotableeding: Woundsts yes OSs se ee ee PAG AEC CMMI ECU ING: Foie she Ae ee ea cit on La Me eg ate Se i ed et At a 18 VVITLIGEPT TCO Gs eh aati a Danes Aa eons er OTE Ny ae, SEEN RRND Wine aig ek (tot 21 Great Ome AT OUNE: ETOGS. eo vie. Baie hoa ee ie Hla Se Oe ee 21 Tah SUIS ST Gaia 0 eee A NE ee one, ia Ste EMO gt See emcee WEL UNE ps ela 22 DiSeaseseandelnSects/ yo.) — ace. ecto eet ee tate een eR nes A et Me Pape Somes Gonmons lrees WSederorsshadew ae 4 wy oe oS, aa en 23 ENTTOGTENCEIIO gL OTT ee Ae Ret ne eh ig ai MR, Tg RMT apc) Ot ayo te 23 Sucare Wanless Hard: Maples jicccs cca ee a eee ere a ee 24 TNIGTENS PEIN 20 LE 6) (CAI eR aa Asa) ees We i De Rane ne ST SA BT die den 25 AN UG) CO Sh peta ae oe tena VR en aa eer age eee ee ac Lah any GA Eg 25 NT pee AN eh oe ITA ee ae de aan: 1 AAR eres oe een, ae 25 SyyComGre, LATTE Tel ee May ee ee ee oe oe 26 Hackberry ys Sum al DELL spe as eter a eo Deep. See ae 26 BASSWOOG eAmericalielLNGdenrsliinte tee we oie, Sees ey reine eee oe 27 PE Ck ia ante tied p42 bn Me oe ten ree a, ee ee 7A 4G: ANG] (SS ake aE iat AD SO a ES gr Me, oO ape ee St 27 SNUGGLE GUMsy FCCC. GoM. ek. as Sev cco Noes as oka Rees. te 27 Ghinesen Whine : [BSN DRAIN HOLE Fig. 13.—Fluxing at cracks in branch crotches frequently can be stopped by tapping the trunk so that the drain hole will cross the crack in the wood. Usually drainage is most effective when the hole is bored to one side and about 6 to 14 inches below the crack. wood creates abnormally high pressures that force the sap out through wounds. This exudation of sap is commonly called flux- ing. Fluxing sap is sufficiently toxic to retard or prevent callus formations. It may kill the bark at the base of pruning cuts and around trunk and crotch cracks. Frequently, the fluxing of wounds can be stopped by tapping the trunk to remove the gas *This section on “Care of Bleeding Wounds” is by Dr. J. Cedrie Carter, Plant Pathologist, Illinois Natural History Survey. 16 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 36 NM TRUNK GRACK DRAIN HOLE DRAIN PIPE R TRUNK CRACK ni DRAIN HOLE ; eR DRAIN PIPE FLUX Fig. 14.—Fluxing at cracks in trunks should be treated the same as cracks in branch crotches. The drain hole should be bored so that it will cross the crack in the wood. It should be about 6 to 14 inches below and to one side of the trunk crack. and toxic sap that have accumulated in the diseased wood, figs. Peel eleleaiioys ‘ There is no hard and fast rule for determining where a flux- ing tree should be tapped. In some cases, tapping the trunk of a large elm at its base has stopped the fluxing of several wounds along the trunk. More effective drainage of the accumulated gas and sap from the diseased wood is usually obtained by tapping the tree a short distance below the fluxing region. Fluxing wounds, where branches have been removed, can usually be drained by boring a hole three-eighths to one-half inch in diameter, 6 to 14 inches directly below the fluxing region, fig. 12. Fluxing cracks in trunks and in branch crotches may or may not respond to the same treatment. In some cases, several holes may have to be bored before satisfactory drainage is ob- tained. The crack in the wood may not be directly behind the fluxing area in the bark. It may be so located that a hole bored directly beneath the bark crack will miss the wood crack, and proper drainage will not result. As a rule it is best to bore the hole to one side and about 6 to 14 inches below the fluxing crack, figs. 13 and 14. This hole should be directed toward the probable location of the crack in the wood or toward the center of the heartwood. Drain holes should have sufficient slant to allow the wetwood sap to flow out, and they should extend through the heartwood to within a few inches of the bark on the opposite side of the trunk. DAVIS: PLANTING AND CARE OF SHADE TREES 17 A short piece of threaded pipe should be screwed into the drain hole to carry the dripping sap away from the trunk and buttress roots. The pipe should be inserted in the hole only far DISEASED TISSUE Em apt ae tay sic a ee Si si OC ee 3 is : mt ig amano Gide ge nen ie Be: a7 ¥ i aces ORS te ae aspen Sok ~ Se ee — , if A va f ) % fF i ; - Fig. 15.—Section of tree trunk showing hole bored at proper angle to insure drainage and drain pipe so inserted that it does not penetrate diseased wood and interfere with drainage. enough to be firm; it should not penetrate the water-soaked wood, fig. 15. If the pipe penetrates this wood, proper drainage will not result. Drain pipes should be examined occasionally and any accumulated slime found clogging the pipes should be re- moved with a piece of wire. 18 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 36 Tree Feeding.” vigorous growth of shade trees, it often becomes necessary to provide food materials that are lacking, or are present in the soil in insufficient amounts. In the forest, where humus accumu- lates year after year, trees are liberally supplied with organic <— WIDTH OF CROWN 44FT-—— ue ———- ‘4 i 5 Oe fia’ ly lig feats ' Get tee ann rain ALA ag. ce OM EEN yal seh) ; fy DSi: Oy, cts un Ot in ath A ey Pe vi RR Wy: } CIRCUMFERENCE OF TRUNK __35 INCHES FREIGHT OF TREE 50) FT. “Vee Fig. 16.—Diagram for estimating the number of pounds of 10-8-6 fertilizer required for a shade tree: circumference of trunk in inches (35) + height of tree in feet (50) + width of crown in feet (44) = 129. At the right is shown the pattern for spacing holes in which to supply fertilizer in soil beneath the tree. The distance from the trunk at which the circles should begin may vary between 6 and 8 feet for large trees. For small trees, the circles should begin closer to the trunk. The distance between circles and between holes in the circles may vary between 2 and 2!) feet. ——_ food material derived from decaying leaves and plants, which also serve to retain an abundance of soil water. Since natural sources of food cannot be maintained along city streets, in lawns, or in parks, artificial feeding may be desirable. Three chemical elements, nitrogen, phosphorus, and po- tassium, must be available in the soil to insure the best develop- ment of a tree. A complete shade tree food should supply all three elements. Nitrogen can be supplied by inorganic com- pounds (nitrate of soda, sulfate of ammonium, calcium nitrate) or by organic materials (urea, soybean flour, cottonseed meal, tankage, dried blood, pulverized sheep manure). Phosphorus can be furnished as superphosphate and potassium as muriate of potash. Although an effective tree food can be prepared from “This section on ‘‘Tree Feeding” is from “Shade Tree Feeding,’’ mimeographed publication of the Section of Applied Botany and Plant Pathology, Illinois Natural History Survey. DAVIS: PLANTING AND CARE OF SHADE TREES 19 inorganic materials alone, it is believed that more lasting effects are obtained when one-third to one-half of the nitrogen is sup- plied by organic materials. There is no established rule as to the amounts of nitrogen, phosphorus, and potassium a tree food must contain. In ferti- lizer formulas, nitrogen is expressed as nitrogen (N), phos- phorus as phosphoric acid (P.0O;), and potassium as potash (K.0). Commonly, tree foods contain nitrogen, phosphoric acid, and potash in proportions of 12-6-4, 10-8-6, 10-6-4, 10-3-3, 8-5-3, 6-7-4, and 6-6-4. Three widely used formulas are 10-8-6, 10-6-4, and 10-3-3. Prepared tree foods can be purchased, ready for use, through many local dealers in fertilizers. One hundred pounds of 10-8-6 home-mixed tree food con- taining an inorganic nitrogen source can be prepared with ap- proximately 47.5 pounds of ‘20.5 per cent available” sulfate of ammonia, 40 pounds of “20 per cent available’ superphosphate, and 12.5 pounds of “48 per cent available’? muriate of potash. A 10-8-6 mixture containing both organic and inorganic sources of nitrogen can be prepared with 30 pounds of “16 per cent available” nitrate of soda, 14 pounds of ‘‘20.5 per cent available” sulfate of ammonia, 2.2 pounds of ‘‘46 per cent available” urea, 23.5 pounds of “6 per cent available” tankage, 17.8 pounds of ‘‘42 per cent available’ double superphosphate, and 12.5 pounds of “48 per cent available” muriate of potash. A common method of estimating the amount of tree food | to be applied is as follows. Add the height of the tree in feet, the branch spread in feet, and the circumference, 1 foot above the soil, in inches, fig. 16. The sum of these three figures repre- sents the number of pounds of tree food required. This method, recommended by A. P. Beilmann of the Missouri Botanical Gardens, has proved very effective for a 10-8-6 mixture. Another method of determining the amount of tree food needed, as suggested by L. C. Chadwick of the Ohio Agricultural Experiment Station, is based upon the amount of nitrogen re- quired to maintain uniform tree growth. Trees less than 6 inches in diameter should receive one-fourth pound of available nitro- gen per inch of trunk diameter, and trees 6 inches and over in diameter should receive one-half pound of available nitrogen per inch of trunk diameter. A tree 4 inches in diameter requires one-fourth pound per inch, or 1 pound, of available nitrogen. To determine the number of pounds of a 10-8-6 formula required to give 1 pound of available nitrogen, divide 1 by 0.10 (10 per 20 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 36 cent available nitrogen). The amount of 10-8-6 fertilizer re- quired is 10 pounds. A tree 12 inches in diameter requires one- half pound per inch, or 6 pounds, of available nitrogen. The amount of 10-8-6 fertilizer required to give 6 pounds of available nitrogen is 6 divided by 0.10 (10 per cent available nitrogen) or 60 pounds. Fig. 16 shows one way of supplying food to trees. With a punch-bar or auger drive holes, 11,4 to 2 inches in diameter, per- pendicularly into the soil beneath the tree. The holes should be 18 to 24 inches deep and spaced 2 to 214 feet apart in concentric circles around the trunk. The outer circles should be somewhat beyond the limit of branch spread and the inner circles should be spaced to maintain about the required distance between holes. Holes may be quite near the trunks of large trees to supply feeding roots in that region. Distribute the tree food evenly in the holes. Then fill the holes with water, and keep them filled for about 3 days, to soak the tree food into the soil and make it quickly available to the feeding roots. The holes may now be filled with sand, peat moss, or loose soil. Or, if left open, they” will facilitate water absorption during rains, aerate the soil, promote development of feeding roots, and provide an effective means of supplying water during droughts. Tree feeding can be done at any time of year but feeding during April, May, or October, when the soil contains ample water, is especially beneficial. Tree foods are most readily avail- able when in water solution; hence, it is highly desirable that sufficient water be present in the soil to dissolve the food. Well- fed trees seem to be more resistant to drought. Although the preceding paragraphs on tree feeding apply specifically to deciduous trees, many of the directions given apply also to evergreens. For evergreen trees in beds or closely planted in rows, apply soybean or cottonseed meal at the rate of 5 to 6 pounds per 100 square feet of ground. Apply 10-6-4 or 8-5-3 tree food at the rate of 2 to 4 pounds per 100 square feet. The tree food should be worked into the top soil by hoeing or watering. For specimen evergreens, those standing alone, the amount of fertilizer to be used must be calculated in another way. Pines, spruces, and cedars can be fed the foods recommended for de- ciduous trees. For shrubby types, apply one-half to one pound ner plant twice a year, in early spring and about June 15. For large specimen trees, apply 2 to 214 pounds of tree food per inch of trunk diameter. Apply in holes beneath the branch DAVIS: PLANTING AND CARE OF SHADE TREES 21 spread. Make 15 holes, 12 to 15 inches deep, for each inch of trunk diameter. Apply the tree food in early spring or in the fall. Feeding holes can be made with a soil auger or punch bar. Watering.—Watering, often essential where tree foods are used, since the food elements can be taken up by the roots only in solution, is also helpful during drought periods and in situa- tions where much of the rainfall is carried away by drainage. Where regular watering is to be done for large trees, a definite system should be used that will carry the water down to the feeding roots. Surface watering is of little value except on level ground where a soil dike can be formed under the outer edge of the crown of the tree, permitting flooding of the entire area beneath the crown. One of the best systems, where flood- ing cannot be used, consists in placing single joints of tile in the ground at regular intervals and watering through these tiles. Four-inch drainage tiles, 12 to 24 inches long, are set upright in the soil, with the tops flush with the surface, and spaced approximately 10 feet apart to form a circle about two-thirds the distance from the trunk to the outer edge of the crown. If the tiles are given all the water that will be readily absorbed from them two or three times a week, trees can be economically watered during dry periods and the water will be distributed down where it can be used by the tree roots. Grading Around Trees.—Appreciably lowering the grade around shade trees in most cases either kills or seriously dam- ages them. If the grade is to be lowered over 12 inches, it is almost’ certain that most of the feeding roots will be removed from the tree. When it is possible to leave the normal grade over the space covered by the crown, even though the grade near it is lowered considerably, the tree may be kept in good condition provided a system of watering is followed to compensate for a lowering of the water table. In many cases shade trees are badly damaged by removal of the roots on one side when streets or driveways are graded, or when excavations for foundations are dug. In such cases trees need help until they can rebuild their root systems. First see that open grades are sodded or riprapped to prevent further loss of soil from the roots by erosion. Then thin out the crown of the tree to reduce water losses by transpiration, and apply fertilizer and an abundance of water for at least two growing seasons. Raising the grade around a tree can be as harmful as lower- 22 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 36 ing the grade. The feeding roots concentrate in a rather limited zone near the surface of the ground where they can get both moisture and air. Raising the grade as much as 12 to 18 inches will not do much harm, but a deeper layer of fill, especially of heavy soil, will exclude air and kill the feeding roots, unless provision is made to carry air down to these roots. Before any fill is made, lay down four or five lines of 4-inch porous drainage tile on the surface of the ground radiating from the trunk of the tree, as spokes of a wheel, out to the edge of the crown of the tree. Then spread a layer of about 4 inches of coarse gravel or crushed stone over the area covered by the crown. On top of this spread about 2 inches of fine stone and 4 to 6 inches of straw or manure. Then, with soil, bring the fill to the level desired. Before the fill is made, or as it is being made, build a brick or stone wall around the trunk of the tree, leaving a space of from 1 to 2 feet between the trunk and the wall. A small tree will need more room than a large tree to allow for its ultimate growth. ; Through the tile, which projects through the wall, air and water can reach the roots of the tree even with very deep fills. The well formed by the wall and the radiating tile make it easy to supply the tree with water and plant food during dry seasons. To supply plant food, determine by the usual method the amount of fertilizer required and then apply it in solution, which will be carried out to the tree roots through the tile. Tree Surgery.—Trees that need attention to cavities, in- stallation of drainage in cavities or crotches, or removal of large limbs, can best be cared for by persons trained in tree surgery work and having the proper equipment for such work. Seldom does the amateur have either the experience or equip- ment to do tree surgery work competently. In some instances minor jobs of this nature can be taken care of by the tree owner, but he should be sure to be properly informed before proceed- ing. A good text for the layman for ordinary tree repair jobs is the U. S. Department of Agriculture Farmers’ Bulletin 1896, Care of Damaged Shade Trees. This bulletin may be secured from the Superintendent of Documents, Washington, D. C., for 10 cents a copy. Diseases and Insects.—Trees that are kept in good health by feeding, watering, and proper pruning are not so susceptible to attacks by diseases and insects as are those that are neg- lected, but any tree, no matter how vigorous, may possibly be DAVIS: PLANTING AND CARE OF SHADE TREES 23 attacked. The diseases and insects that attack trees are so numerous that it is not possible to give detailed information about them here, and the reader is referred to University of Illinois College of Agriculture Extension Circular 509, Protect- ing Shade Trees from Insect Damage. The Illinois Natural History Survey, through its sections of Economic Entomology and of Applied Botany and Plant Pathol- ogy, is glad at any time to examine specimens to identify insects or diseases and make recommendations for their control. This service is offered without charge and should be used more fre- quently. Too often persons hesitate to ask advice on control of diseases and insects until the damage has gone beyond repair. In submitting diseased leaves and twigs for inspection, send adequate samples of fresh specimens, well wrapped so that they will not dry out. Send insects, without crushing them, in mail- ing tubes or in tin boxes, but not in tightly stoppered bottles nor loosely in envelopes. Be sure to send specimens of the damage being done by the insects and give all information you can about the conditions involved. Mail specimens to the Illinois Natural History Survey, Urbana, Illinois, or to the Extension Forester, 219 Mumford Hall, Urbana, Illinois. SOME COMMON TREES USED FOR SHADE American Elm (Ulmus americana) .—This is the most popu- _ lar and widely planted shade tree in Illinois, fig. 17. Its vaselike form and dense, dark green foliage make it both pleasing in appearance and a provider of good shade. However, the Ameri- can elm is susceptible to two serious diseases—the Dutch elm disease and phloem necrosis. Although the Dutch elm disease has not been found in Illinois, it has been present at Indianapolis, Indiana, and in several eastern states for over 15 years. Phloem necrosis is prevalent in the southern part of Illinois, extending as far north as Peoria. It affects only the American elm and its varieties, including the Moline, vase, and holly leaf elm, and the winged elm (Ulmus alata). In view of the present seriousness of this disease, it is advisable to include other species of trees in plantings for shade and ornamental purposes. Several varieties of American elm have been propagated because of their pleasing shapes. Many of them have narrow or V-shaped crotches. As the trees increase in age and size, such crotches make them subject to storm damage, weakening and death of scaffold branches because of crowding, and invasion 24 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 36 Fig. 17—The American elm is the most popular of all shade trees in Illinois. by borers. Elms with broad or U-shaped crotches are less sus- ceptible to these troubles. Sugar Maple, Hard Maple (Acer saccharum).—Not so fast growing as the American elm but a very useful shade tree Fig. 18.—The sugar maple has a dense crown that affords heayy shade. DAVIS: PLANTING AND CARE OF SHADE TREES 25 throughout the state, the sugar maple has a dense, symmetrical crown that affords heavy shade, fig. 18. The fall leaf colors vary from yellow to rich burnt orange. The hard maple is deep rooted and seems to withstand well the difficult growing con- ditions in cities. Norway Maple (Acer platanoides).—This is not a native tree and cannot be found in local woodlands, but it is frequently used as a street tree and may be planted throughout Illinois. It has a low-branching, round crown with a very dense foliage. A disadvantage of this tree is that its heavy shade and its feed- ing roots very close to the surface make difficult the growing of grass underneath it. The Oaks.—The white oak (Quercus alba), the red oak (Quercus borealis maxima), and the pin oak (Quercus palustris) are of special interest as shade trees because of their dense foli- age and rich autumn colors. They are well adapted to the en- . 9 tire state of Illinois. The white sil oak and the red oak develop large, spreading crowns, and the pin oak develops a conical crown, narrow at the top and wide spreading at the base. The pin oak, fig. 19, is useful where a large upper crown is undesira- ble, but it is not adapted to a limited ground space, such as the parking between sidewalk and curb. The wood of the oaks is very strong and storm resist- ant, and not seriously suscepti- ble to diseases, fig. 20. Tulip Tree (Liriodendron tulipifera).—The tulip tree has a very unique foliage of light green color. It tends to grow tall and upright with a straight clean trunk and symmetrical aves crown. It is not hardy in the’ Fig. 19.—The pin oak develops a northern end of the state, nor is ‘Shapely, conical crown. This ; : species of oak is not adapted to a it adapted to dry sites. limited ground space, however. Yee er Aad, jeethy A ’ *¥ BS peyes >» Net » : OR ee rat oy ne % pe At eh ls ‘4 26 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 36 Sycamore, Buttonball, Plane Tree (Platanus occidentalis) .— The sycamore is delightful as an occasional tree because of the appearance of the bark, which is shed annually, leaving a mottled effect of whitish and gray-green patches. This tree will grow Fig. 20.—The wood of the oaks is strong and storm resistant. The autumn leaf colors vary from brilliant to deep reds. A bur oak is shown here. large and tall but will not make dense shade. It can be used throughout the state but is not adapted to dry sites. The syca- more is susceptible to disease and storm damage and should, therefore, not be used extensively. The objection to its use in the yard is that it sheds its leaves over a long period of time. Hackberry, Sugarberry (Celtis occidentalis).—The hack- berry is similar to the elm in form but has finer foliage. It can be grown almost anywhere in Illinois and has been widely used as a street tree. It is not so resistant to decay as the elm. One disadvantage of the hackberry is its susceptibility to a disease which forms witches’ brooms (dense clusters of short branches) throughout the crown and often makes the tree unsightly. The DAVIS: PLANTING AND CARE OF SHADE TREES 27 fruit of the hackberry is readily eaten by both squirrels and birds. Basswood, American Linden, Linn (Tilia glabra).—The basswood does not make so pleasing a shade tree as the European lindens, but where it can be readily obtained locally it is satis- factory. The leaves are large and heart shaped, and always present a fresh, cool appearance. The wood is weak and easily damaged by storms. The basswood is not adapted to the south- ern part of Illinois. Black Walnut (Juglans nigra)—The black walnut differs from the trees previously described in that it has long compound leaves which give it a quite different appearance. It makes a tall, upright tree, providing fairly dense foliage, and is adapted for planting throughout the state. The special interest of the walnut lies in its fruit. Every city should have walnut trees scattered throughout its plantings to provide food for squirrels. However, it should not be planted where the walnuts will fall on sidewalks, as the hull when crushed makes an unsightly stain on stone or concrete. The Ashes.—The white ash (Fraxinus americana), the green ash (F'raxinus pennsylvanica lanceolata), and the blue ash (Fraxinus quadrangulata) are adapted to a wide variety of soils throughout Illinois. The ashes form tall, fairly narrow trees, with light foliage. They are not so useful for shade as the other trees described, but they have a definite place as an occasional tree to add variety. Sweet Gum, Red Gum (Liquidambar styraciflua).—The sweet gum is an excellent shade tree well adapted to the central and southern parts of Illinois. The crown is usually symmetri- cal and not so wide spreading as that of elm or white oak. The leaves are star shaped and light green in color, turning to bril- liant reds in the fall. ; Chinese Elm (Ulmus pumila).—This is one fast-growing tree that can be used to a limited extent for shade planting, particularly for temporary shade. Its leaves are small and its foliage fairly thin, so that its shade is very light. Its wood is stronger than that of the objectionable trees listed below, but it is still very weak and easily damaged by storms. Apparently there are several strains of the Chinese elm, some of which are better adapted than others to Illinois climate, but as yet no intensive study has been made for the purpose of testing and selecting the better strains. The tree has not been planted in 28 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 36 this state long enough to allow the making of any predicticns on its longevity. Other Useful Trees.—The above brief descriptions include a few of the commonest native trees, which can ordinarily be collected as wild saplings or readily obtained from local nurs- eries. Of the trees described, only the Norway maple and the Chinese elm are not native. The list represents by no means the limit of varieties that can be successfully used for shade tree planting. Many other native trees are useful for shade. No attempt has been made to list the many highly desirable introduced trees which, of course, cannot be obtained from local fields or woodlands. Before doing any shade tree planting it is advisable to consult nursery catalogs to become acquainted with all types of trees that are suitable for planting in Illinois. Trees to Avoid.—There is always a demand for trees that will grow rapidly, but, unfortunately, the fast-growing trees are weak wooded and very susceptible to diseases and storm damage. For these reasons, the following trees are objection- able and should generally be avoided in shade tree planting: Silver maple (Acer saccharinum), box elder (Acer negundo), tree of heaven (Ailanthus altissima), the catalpas (Catalpa spe- cies), the poplars (Populus species), and the willows (Salix species). The poplars and willows are objectionable also because of their habit of growing into sewers and drainage tile. The white birches, particularly the weeping varieties, cannot be recommended because they are likely to be killed by the bronze birch borer, often at about the age they have reached a useful and attractive size. Recent Publications A.—ILLINOIS NATURAL HISTORY SURVEY BULLETIN. Volume 22, Article 2.—Studies of North American Plecoptera, with special reference to the fauna of Illinois. By T. H. Frison. September, 1942. 122 pp., frontis. + 126 figs., bibliog., index. $1.00. Volume 22, Article 3—Management of Small Artificial Lakes: a summary of fisheries investigations, 1938-1942. By George W. Bennett. Febru- ary, 1943. 20 pp., frontis. + 7 figs., bibliog. Volume 22, Article 4——-The Prairie Chicken in Illinois. By Ralph E. Yeatter. May, 1943. 40 pp., frontis. + 18 figs., bibliog. (Bound with Article 5.) Volume 22, Article 5.—Preferential Rating of Duck Food Plants. By Frank C. Bellrose, Jr.,. and Harry G. Anderson. May, 1943. 16 pp., frontis. + 16 figs., bibliog. (Bound with Article 4.) : Volume 22, Article 6.—Survey of the Illinois Fur Resource. By Louis G. Brown and Lee E. Yeager. September, 1943. 70 pp., frontis. + 33 figs., bibliog. (Bound with Article 7.) Volume 22, Article 7.—Illinois Furbearer Distribution and Income. By Carl O. Mohr. September, 1948. 33 pp., frontis. + 24 figs., bibliog. (Bound with Article 6.) Volume 23, Article 1.—The Caddis Flies, or Trichoptera, of Illinois. By Herbert H. Ross. August, 1944. 326 pp., frontis. + 961 figs., bibliog., index. $1.50. Volume 23, Article 2—Duck Populations and Kill. By Frank C. Bell- rose, Jr. November, 1944. 46 pp., frontis. + 27 figs., bibliog. Volume 23, Article 8.—Overfishing in a Small Artificial Lake: Onized Lake Near Alton, Illinois. By George W. Bennett. May, 1945. 34 pp.,- frontis. + 15 figs., bibliog. Volume 23, Article 4—Wetwood of Elms. By J. Cedric Carter. August, 1945. 42 pp., frontis. + 30 figs., bibliog. Volume 23, Article 5.—Fox Squirrels and Gray Squirrels in Illinois. By Louis G. Brown and Lee E. Yeager. September, 1945. 88 pp., frontis. + 42 figs., bibliog. Volume 24, Article 1—The Mosquitoes of Illinois. By Herbert H. Ross. August, 1947. 96 pp., frontis. + 184 figs., bibliog., index. 50 cents. B.—ILLINOIS NATURAL HISTORY SURVEY CIRCULAR. 32.—Pleasure With Plants. By L. R. Tehon. November, 1942. (Second printing, with revisions.) 32 pp., frontis. + 9 figs. 33.—Controlling Peach Insects in Illinois. By S. C. Chandler and W. P. Flint. August, 1989. 40 pp., frontis. + 32 figs. 34.—Rout the Weeds! Why, When and How. By L. R. Tehon. September, 1946. (Fourth printing, with revisions.) 48 pp., color frontis. + 13 figs. 39.—How to Collect and Preserve Insects. By H. H. Ross. May, 1944. (Second printing, with additions.) 55 pp., frontis. + 63 figs. 41.—How to Recognize and Control Termites in Illinois. By B. G. Berger. February, 1947. 44 pp., frontis. + 32 figs. ; C.—ILLINOIS NATURAL HISTORY SURVEY MANUAL. 2.—Fieldbook of Illinois Land Snails. By Frank Collins Baker. August, 1939. 166 pp., color frontis. + 170 figs., 8 pls. $1.00. 3.—Fieldbook of Native Illinois Shrubs. By Leo R. Tehon. December, 1942. 307 pp., 4 color pls. + 72 figs., glossary, index. $1.25. List of available publications, about 400 titles, mailed on request. Address orders and correspondence to the Chief ItLtiNois NaturAL History SURVEY Natural Resources Building, Urbana, Illinois Payment preferably in the form of U.S. Post Office money order made out to tate Treasurer of Illinois, Springfield, [inois, must accompany request for those publications on which a price is set. P wy ‘ “iI 3 0112 01754118