154 TREES AS GOOD CITIZENS 



of receiving nourishment, while the lower edge is out of the 

 direct channel and is less generously supplied. Thus it is 

 obvious that a tongue of bark, projecting above the lower 

 edge of a wound or bark below a broad wound, cannot 

 receive its share of sap, and must therefore languish and 

 die. Even on the upper edge a projection is undesirable, 

 but it has better chance than a similar tongue on the 

 lower edge. From this it is clear that the wound should 

 have its edges so trimmed as to make as little top and 

 bottom as possible. In other words, the wound which 

 has its longest dimension parallel with the limb and the 

 shortest dimension across it, is the one which will heal 

 most rapidly. These factors should be borne in mind in 

 trimming the edges. 



In connection with injuries to the bark it must be 

 remembered that bark which has been seriously damaged, 

 or which has been torn loose from the trunk, can never 

 be made to resume its growth. Efforts are sometimes 

 made to induce growth by fastening the bark to the tree 

 with nails or otherwise. This not only does no good, but 

 works still further damage by making an attractive rendez- 

 vous for insects and decay. The only thing to do in a case 

 of this kind is to cut away the loose and injured bark and 

 apply protective coverings. 



Freezing sometimes does more or less serious harm to 

 trees which have been transplanted from warm climates 

 into regions of severe cold. Cracks or splits in the bark 

 and wood, caused by alternate freezing and thawing, 

 invite disease and decay. The wounds should be treated 

 as soon as they become apparent, which is usually during 

 the summer, when the bark splits away from the wood. 

 Injured parts should be cut away and the surface given 

 a protective coating. Wrapping the trunk of a tree with 

 burlap or straw, before cold weather, will prevent frost 



