PRUNING SHADE TREES 139 



given attention. If the roots have been broken or other- 

 wise injured in digging or handling, the injured portions 

 should be removed by clean cutting with a sharp knife. 

 Healing and the natural growth of the root will progress 

 from a surface which has been cleanly cut, while decay 

 and death are likely to follow the ragged break or abrasion. 

 For the top pruning there should be removal of all 

 branches that can be spared. The amount to be pruned 

 varies with species. Oaks, for instance, require much 

 more cutting than do Norway Maples and Elms, but in 

 many cases it may be said that three-fourths of the leaf- 

 buds should be removed. This may seem drastic, but it 

 is necessary for satisfactory growth. The purpose of the 

 seemingly severe pruning is to reduce the amount of leaf 

 surface the tree must support the first year. This 

 decreases the amount of moisture that must be supplied 

 to the top by the roots, and the lessened drain enables 

 the root system to use this strength in becoming firmly 

 established in the soil. In this pruning it is not always 

 necessary to interfere with the shape of the crown, but 

 even when it does involve such sacrifice the pruning 

 should be done. Form can be regained after the tree has 

 become established, but proper growth cannot be achieved 

 without the preliminary pruning. New growth, to replace 

 the branches which have been cut off will start close to 

 the stem, and this serves a useful purpose through estab- 

 lishing a compact top. Without this pruning the tree 

 may not live, and even if it does survive, its crown will 

 be ragged and its foliage lacking in density. 



In pruning at planting time, where only the end of a 

 branch is to be removed, the cutting should be done 

 immediately above a strong bud, and care should be taken 

 to see that the bud which remains is one which points 

 in the direction toward which growth of the limb is 



