164 ELEMENTS OF SYLVICULTURE. 



only too often proved groundless when the tree is cut 

 up. Not only does each branch lopped off give rise 

 to solution of continuity, but it is very rare to find a 

 wound covered over before decay has set in. Decom- 

 position may then make very slow progress, but it 

 never ceases. Wounds covered over fifteen or twenty 

 years ago nearly always conceal hollows underneath, 

 and often the mischief is propagated downwards, so 

 that the length of bole artificially obtained is worth- 

 less if it has not even rendered valueless the rest of 

 the bole. From this the necessary conclusion is 

 that no live branch of more than one to two inches 

 in diameter should be lopped off from standards of 

 the second and higher classes, because at the time 

 of felling there is sure to be a fault of a more or less 

 grave character in the very heart of the wood. 



It must not be forgotten that in a living tree every 

 portion of the wood, which is exposed, necessarily 

 dies. The wound may heal up more or less rapidly; 

 decomposition to a less or greater extent may 

 previously set in; but there can never be any 

 coherence between the dead portion of the wood and 

 the subsequent rings which cover it. The different 

 substances, with which the section is sometimes 

 coated, have only the effect of delaying decomposi- 

 tion; they cannot prevent the wood from dying. 

 Little wounds, like those caused in pruning off 

 epicormic branches or lopping off small branches in 

 the crown, have little or no injurious effect. This 

 no longer holds good in the case of the principal 

 branches, the lopping off of which, close to the bole 

 (the only mode of rapidly obtaining a covering of 



