612 AMICRICAN FORESTRY 



more susceptible to insect attack. Street elms without care very seldom escape 

 attack from tlie elm leaf beetle and such trees as the horsechestnut and linden 

 are titbits for leaf-eating caterpillars. Let all such spraying be done early, 

 while the insect is young and susceptible to the poison. It is also important 

 to look into the chemical and physical value of the insecticide you are using. 



A few years ago I found one of the best known brands of arsenate of lead 

 to contain as little as 4 per cent of arsenic oxide, whereas it should have had 

 15 per cent or more to be the least effective. Since then, we have been purchas- 

 ing our spraying material subject to chemical and physical tests and have been 

 paying considerably less than we had been paying before. 



Success in spraying will, moreover, depend not only on the value of the 

 insecticide and upon how early in its feeding stage the insect is attacked, but 

 also on the thoroughness with which the work is done. The kind of apparatus 

 used will also make an appreciable difference, for a barrel pump is too slow for 

 the amount of labor used to operate it and a very heavy wooden tank such 

 as is commonly used for woodland spraying would prove too sluggish and 

 cumbersome in going about the city streets. 



In late summer and early fall, pruning will be in season. The men should 

 then be trained in the fundamental principles of the work and furnished with 

 printed hints on the necessary precautions in climbing trees and removing 

 branches. We have had little booklets published on such topics for our men 

 and find them very helpful. Close cuts and application of coal tar to the 

 wounds should always be insisted upon and above everything else, do not let 

 them prune more than is necessary. The tendency on street trees has gener- 

 ally been the other way to the great detriment of the trees. 



Cavities caused by some old neglected horse-bitten wound or by an improp- 

 erly made cut, are more common in street trees than in park trees and the 

 present tendency is to indiscriminately fill them all with cement. This work is 

 expensive and in many cases unjustified. It is particularly true of trees on 

 the streets because there the trees are frequently of poor species and the 

 cavities so neglected that the absolute elimination of diseased wood is utterly 

 impossible. There the decay would keep on developing after treatment with 

 the same rapidity as before. Cavity filling is justifiable only where the tree 

 is a much valued specimen, where the filling can serve the practical purpose of 

 eliminating moisture and where every trace of diseased wood can be thoroughly 

 removed before the filling is inserted. In many cases the proper use of the 

 chisel or gouge alone without the filling will eliminate all disease and leave 

 the wound in a position where moisture will not collect. The absolute eradica- 

 tion of all infested wood from a neglected cavity is often impossible and in 

 many cases where this is true, the axe is by far the safest and most practicable 

 tool. Street trees especially should be cut down as soon as they become the 

 least dangerous or when their trunks become hollow or badly infested with 

 disease. For, as soon as the citizen notifies the authorities of the condition of 

 his tree, all responsibility is shifted on the city and law suits are sure to follow 

 in case of any subsequent damage. 



Spring is the time for planting, but the preparations for planting should 

 be commenced in the fall. Fall is the time to purchase trees and leave them 

 standing labeled in the nursery for spring delivery. Holes in the sidewalk 

 about 5 feet long and o feet wide and 3 feet deep may be opened in the fall and 

 the ashes, tin cans and beer bottles frequently composing a street soil may be 

 changed for a cubic yard of rich black loam. 



In selecting the trees for street planting consideration should be given not 

 only to the si)ecies but to the specimen as well. The specimen tree should be 

 about 21/2 inches in diameter, should possess a straight trunk, a definite leader 



