54 



BULLETIN 816, U. S. DEPAKTMEE"T OF AGRICTJLTUKE. 



made to change or distort a tree from its normal habit of growth. 

 Successful pruning will accentuate rather than disguise a tree's 

 characteristics. 



All cuts should be made so that no stubs or protuberances are left 

 to prevent quick healing. Small wounds need no after treatment if 

 the cut is weU made. Large wounds should have the wood of the 

 center of the cut well protected to prevent decay until the new growth 

 has had an opportunity to heal over the cut. An application made to 



the center of the cut 

 to preserve the wood 

 should not be per- 

 mitted to come near 

 the cambium layer 

 or inner bark, espe- 

 cially of soft-wooded 

 trees like the tulip 

 and magnolia, as the 

 oil or other sub- 

 stances contained in 

 the paint, tar, or 

 other covering may 

 spread to the cam- 

 bium layer and kill 

 it. It is well not to 

 make any applica- 

 tion within half an 

 inch of the outside 

 of the wound unless 

 the coating has been 

 thoroughly tested. 



Dead wood should 

 be entirely removed, 

 the cut being made 

 through good live 

 tissue. E-emoving such wood frequently exposes decayed cavities, 

 usually from bad stubs or injuries which have started decay that has 

 followed back to the main limbs or the trunk. The treatment of 

 such cavities is the province of tree surgery and is discussed in 

 another publication.^ 



One source of trouble with a large tree that has developed with 

 two trunks or branches instead of three or more is the liability of their 

 splitting apart in the crotch. This is especially characteristic of the 

 elm. Careful attention to the early pruning of trees may eliminate 



P2037IHP 



Fig. 37.— Part of a tree tniak showing proper and improper methods 

 of removing old limbs. Although healing has started on the stub 

 (at the right) it is likely to proceed very slowly. The nearer the 

 cut is to the tree the larger the wound but the less conspicuous the 

 stub will be when healed. 



1 Collins, J. r. Practical tree surgery. In U. S. Dept. Agr. Yearbook, 1913, pp. 163-190, pi. 16-22. 

 Published as Yearbook Separate 622, obtainable from the Superintendent of Documents for 10 cents in coin. 



