104 ELEMENTARY FORESTRY. 



This is only necessary for winter protection. The neglect to 

 properly heel in nursery stock as soon as it is received is 

 undoubtedly a frequent cause of failure. 



Trees and cuttings will sometimes get so dry in shipment 

 that the bark shrivels. In such cases the best treatment is to 

 bury them entirely for a few days, which will often enable 

 them to recover. 



Figure 20. HEELING IN. Various stages of the operation, 

 (a) Row of trees with roots covered, (b) A row bent down and 

 the tops covered at (c). 



Soaking in water will answer the same purpose, but unless 

 very carefully done is likely to injure the wood. 



PRUNING. 



Pruning should be avoided as much as possible and yet 

 be done sufficiently to secure the effect desired. If it is begun 

 early in the life of a tree, no large branches need ever be 

 removed, the most desirable pruning being the directing of the 

 growth by pinching off the buds that would develop into 

 undesirable branches: but this is impracticable on a large 

 scale and for this reason in ordinary practice it is often 

 necessary to do more extensive pruning. 



The Purpose in Pruning Trees is to give them forms that are 

 desirable for the purpose intended; for example, a tree for the 

 lawn or windbreak may be most desirable when covered with 

 branches even down to the ground, while street trees should 

 have a trunk free from branches for eight or ten feet from the 

 ground. Many of the evergreens and some other trees used 

 for ornament naturally take on so regular and desirable a 

 form that it is not necessary to prune them except perhaps to 

 pinch or cut off an extra leading shoot that is likely to make 

 a forked top, while the White Elm, Soft Maple and others 



