PRUNING. 99 



shorten back in summer those that are to be removed later; by 

 such treatment a large part of the strength of the tree goes into 

 the top without increasing the size of the lower branches, which 

 may be removed in a year or two without injury to the tree. 



(3) After pruning paint the wounds with good white lead 

 paint, to keep the wood from decaying and the injuries from thus 

 becoming permanent. This is not so necessary on very hardy 

 trees as on those that are somewhat tender. 



(4) Where branches rub together it is generally best to 

 remove one of them. 



(5) Where bad crotches are being formed by the develop- 

 ment of two leaders, severely check the growth of one of them 

 by shortening it, thus throwing more sap into the other and 

 making it the leading shoot. 



(6) Prevent the formation of long side branches by shorten- 

 ing those that are liable to become too long. This is especially 

 desirable with the Soft Maple, which has a tendency to form 

 long branches that are likely to break off unless occasionally 

 pruned. 



(7) Where trees have lost their leaders, prune so as to 

 develop one of the side branches into a leading shoot. This the 

 tree always attempts to do itself, but a little judicious pruning 

 will greatly aid it. 



(8) Every species of tree and shrub has its own natural 

 form, and in pruning do not try to make all of them of one. 

 shape. Study the natural form of each kind of tree, and encour- 

 age the development of this form. 



(9) When trees are full of frost the wood cracks very easily; 

 therefore do not prune in very cold weather, for bad wounds 

 may then be easily formed. 



Treatment of Crooked Trees. It is common to have some 

 trees in the nursery that are of vigorous, healthy growth, but so 

 crooked as to be nearly worthless. The proper treatment for 

 most of our shade trees when in this condition in the nursery, 

 if anything is to be made of them, is to cut them off at the sur- 

 face of the ground, early in the spring, and then select one of the 

 good, strong sprouts that come from the roots of each tree, 

 train it into a straight stem, and cut away the others. Treated in 

 this way well-formed trees may soon be grown. Such treatment 

 may also be desirable with small street trees that have their stems 



