178 PRACTICAL TREE REPAIR 



also Included in it discussions of various methods 

 of treating cavities which premise a complete ex- 

 cision of the decayed wood, but which do not call 

 for the filling of the cavity. 



The most important way in which the life of a 

 tree in an advanced stage of decay can be pro- 

 longed is by severe pruning and liberal manuring. 

 The pruning takes off much of the strain on the 

 tree and invigorates the remaining parts. Al- 

 though this treatment does not, strictly, fall within 

 the legitimate field of this book, on account of the 

 vital interest of the subject to almost every per- 

 son who is likely to look into a book of this kind, 

 I shall venture to quote here a few lines from two 

 editorials, written by the editor. Prof. Sargent, 

 which appeared in the old " Garden and Forest." 



" The vigor of a tree depends upon the power 

 of its leaves to elaborate plant food. The larger 

 the leaf surface exposed to the light, the greater 

 will be the vigor of the tree. The object of prun- 

 ing, therefore, is to increase leaf surface. If 

 half a branch of a decrepit tree, bearing small and 

 scattered leaves, is cut away, the leaves which 

 will grow upon the half which is left will be so 

 large that their total area will often be more than 

 double the total area of the leaves upon the whole 

 branch before it was cut. ... A tree on the de- 

 cline should have its main branches all shortened 

 In from one-third to one-half their length. . . . 



