Part II

that they interfere with electric wires, either have the wires lowered, or remove entirely all but the three or four most vigorous shoots and stimulate the tree to carry a crown above the wires. (See p. 19.) For treatment of heavy limbs see Injuries, page 15. Vigor. If a tree is so weakened that dry branches appear, cut out all the dead wood, and such of the living members as is necessary to make the tree shapely. If lack of vigor is shown by droop- ing foliage and the crown is very dense (as is common in Norway maples and sugar maples), relief will be given by removing a quarter or a third of the foliage. This should be done, not by cutting off the extremities, but by taking out interior branches entire (figs. 8, 9). When done skilfully the appearance of a tree as well as its strength is improved. After pruning for vigor a tree should always be well fertilized and watered. Fig. 8. Diagram, from a Photograph, of a Norway Maple Showing the very Dense Crown Common with this Species. The Foliage Produced Makes a Heavy Draft upon the Soil Fertility and Water and Frequently Leads to Wilting. Fig. 9. The Same Norway Maple as that Shown in Fig. 8 with Superfluous Branches Removed by an Interior Pruning. This Preserves the Natural Form of the Crown and a Frame that will Produce as much Foliage as is Desirable. Covering' cuts. Unless it is properly treated every break in the bark of a tree affords entrance to disease germs. In practice clean cuts less than an inch in diameter are ignored ; every larger wound should be coated with an antiseptic. The most practical is creosote followed by coal tar. Tar alone is often used, but does not pene- trate deep enough to give best results. Creosote is a dark oil and can be applied with a brush. Tar should be made liquid by heat and applied in the same way. It is advisable to avoid covering the cambium. INJURIES. 15 Time to prune. Pruning may be done when it is most convenient unless "bleeding" (p. 21) is induced. That is most apt to occur in early spring or early fall. Late winter is usually best because there is then little sap movement and the absence of foliage makes the work easier. (See p. 8.) Injuries Broken limbs. Every broken limb should be cleared away promptly by a cut, or succession of cuts, that leave a wound which will heal quickly. Small limbs can be taken off by a single cut, larger ones require three, as indicated at B, figure II. It is im- portant to use a sharp saw, make the final cut close to the larger A member and be careful that the bark at the bottom is not torn. wound shaped as indicated at right, figure 10, will heal most quickly; one shaped as indicated at wrong will heal more slowly at the top because the arch is flatter, and very slowly at the bottom be- A cause the bark is torn away. stub as at C, figure 11, should never be left. The face of the wound should be treated as directed on page 14. Cement will do harm rather than good. .'Jill mWRONG Fig 10. Cut Marked RIGHT is Healing Properly and Quickly. Cut Marked WRONG is Healing Slowly, and Not at All at the Bottom, Where the Bark is Torn. Every Wound on a Tree that Can be so Treated, Whether a Mere Bark Bruise or the Stub of a Severed Limb, Should be Trimmed to a Long, Regular Oval. 16 SHADE TREE GUIDE. Frost cracks, sun cracks, and winter kill. Extremely cold weather, especially when it follows a late growing season, some- times freezes the water in the outer cells of a tree stem and causes a long crack. Thin-barked species, like sycamore and horse chest- nut, are most susceptible and any tree on a street, exposed as it must be, is apt to suffer. Sun cracks have the same appearance but are caused by excessive heat, often reflected from a white pave- ment or wall. In large trees such cracks usually close again with warmer weather and no serious harm is done, but the wood does On not unite and a scar is left. small trees the crack is apt to per- sist until new growth covers it. There is no practical preventive, and no remedy other than helping nature by every care to heal the wound. This can be hastened by treating the crack with antiseptic, and keeping it from reopening by strong staples, driven in warm weather when the gap is narrowest. "Winter kill" occurs when the vital parts of a tree trunk are frozen and ruptured in a horizontal plane by the formation of ice about its base. There is no remedy, but the trouble can usually be avoided by having the ground slope away from the foot of a tree on all sides so that no water can collect there. "Winter kill" is common on the terminal shoots of many trees and shrubs and rarely does permanent harm. Abrasions. Surface wounds, made by horses, lawn mowers, blows, etc., are the starting places of most of the decay that destroys shade trees. It is little realized that many serious tree wounds originate between the nursery and the planting site. If the trunk of a young tree is thrown on the side-board of a wagon the tender bark and cambium are apt to be crushed, and tho the injury may not show at the time the growth of the surrounding parts reveals it. Every care should be taken to avoid these injuries. When one occurs let the injured part be cut out carefully with a sharp knife -- or chisel until sound wood is exposed and the edges left smooth. Then sterilize and tar the wood not the cambium or bark, and leave the rest to nature. Cement should not be used. (See F and H, fig. ii.) Cavities. Cavities in trees are invariably the result of decay. They are treated with one or all of three objects in view: (i) to stop the decay and induce healing; (2) to hide an unsightly part; (3) to support a weakened body. The belief that every cavity should be filled is wrong, because, even with the best workmanship, a filling merely retards decay, it does not stop it. The best rule is -- to clean a cavity thoroly cutting out all decayed tissue with a gouge and mallet until sound heart wood is exposed. If the cavity will not hold rain water, or the wound is not unsightly, trim the edges neatly, treat the wood surface and stop. INJURIES. 17 PREVENT A SPLIT OR MEND A SPLIT BT CHAIN a BOLTS, NOT BY A BAND, A PRUNING WOUND MADE AS B 0(1 � HEALING PERFECTLY. A WOUND FILLED UNNECESSARILY, TREATMENT AS E OR K WOULD BE BETTER. NEVER MENDA SPLIT WITH A BAND. THE TREE WILL SOON BE CHOKED, SCEA&O A HORSE BITE OR BRUISE TO BE TREATED AS F. A LONG STUB LEFT, DECAY HAS SET IN M a IFNOT TREATED AS AT WILL DESTROY THE MAIN Line. A SOLID BARWITM NUTS WILL HOLD A WEAKENED CROTCH, THOUGH, IN A BIG TREE. NOT SO WELL AS A CHAIN. -SEE A. . WHEN A LIMB IS REMOVED AND THERE IS SLIGHT DECAY, CLCAN OUT THE WOUND & TAR BUT DO NOT FILL IT. HTREAT A BRUJSE AS BY CUTTING OUT INJURED TISSUE, LEAVING SURFACE & EDGES SMOOTH, TAR BUT DO NOT FILL. A LARGE CAVITY PROPERLY FILLED WITH CONCRETE. Fig. 11 The Right and Wrong of Tree Doctoring. If the cavity cannot be drained, if it is unsightly, or if the tree needs support, a concrete filling may be placed. Before doing this any but a pocket cavity should be shaped so that moisture will drain from it, and set with nails or wires to hold the concrete in place. In many cases it is advisable simply to clean the cavity, and, 18 SHADE TREE GUIDE. without attempting to fill it, cover the opening with cement, sheet- metal, or wood blocks (creosoted), to guide the growing callus. For small cavities a mixture of half cement and half sand is best; for larger ones one part cement, one part sand and two parts gravel, broken stone or cinder will answer. The surface of a filling may be smoothed with a coat of clear cement. The sand, stone or cinder should always be free from dirt of any kind, the cement thoroly mixed and as soft as it can be handled. Gas poison. If illuminating gas escapes from a faulty pipe into the soil in which a tree grows the roots may be poisoned, cease to function and the tree be weakened or killed. The extent of the damage, and the rapidity of action, depend upon the quantity of gas, the porosity and moisture of the soil, and the character of the pave- A ment or other ground cover. little gas may find its way to the air and do no great harm ; a large quantity can kill in a day every tree whose root system it penetrates. If a tree is killed while it is leafless, it may give no sign until the following spring when its foli- age fails to come out, or, coming out, is weak and soon falls. The only sure test for gas is the odor. If a leak is suspected make a hole with a crowbar or auger about two feet from the tree and two or three feet deep and apply one's nostrils to the opening. If gas is indicated the leak must be found and stopped at once. Some- times a tree subjected to gas can be saved by trenching about it and watering the soil freely, but most cases are hopeless unless only a. little gas has escaped. Fire must not touch a valued tree. Even the slight heat given off by a burning leaf pile may cause serious injury. Salt, lime. Many trees are killed by having brine from ice- cream tubs, or from salt used to melt pavement ice, penetrate to their roots, and some are lost by an excess of lime water washed from nearby mortar beds. Preventive measures only are effective. Electricity. Ordinary electric currents never injure the vitality of a tree, and wires carrying a high potential current which might do damage, especially in wet weather, are bound to be properly in- sulated to save loss of power. The injury that trees suffer from electric wires is invariably a