232 



ELEMENTS OF AGRICULTURE 



FIG. 118. Most of the apple trees in the 

 northeastern states are killed in this way. 

 (See Figs. 119 and 120.) 



wood has no use except to support the tree; but, sooner 

 or later, it is certain to be blown down (Fig. 118). A 

 great majority of the trees in forests and orchards die 



because of rotten trunks 

 that give way during a 

 wind. 



In order to prevent 

 trunks from rotting, care 

 should be exercised not to 

 hurt trees with machinery 

 or to allow them to be in- 

 jured by stock. They 

 should be pruned when 

 young, so as to avoid the 

 necessity of removing large limbs. If such limbs have to 

 be removed, they should 

 be cut in the manner that 

 will make them heal fast- 

 est. All large wounds 

 should be painted, so as 

 to protect the wood until 

 it heals over. 



Wounds heal most rap- 

 idly when cut parallel 

 with the branch, and as 

 close to it as possible. 

 This makes a much larger 

 wound; but it is in line 

 with the cambium layer 



and heals in leSS time, as FIG. 119. The decayed hole where a 



. , . limb was removed. The wood-destroying 



proved by experiments. f ung i caused the tree to break, Fig. 118, 



