VI.] 
PRUNING. 
37 
during its growth, must still be looked to after it is 
felled, since, if neglected, there being no longer any 
check to its development, fresh moisture will be 
absorbed, decay will be accelerated, 
and the whole log soon destroyed. , 
To guard against this, it would be 
proper, as soon as the log is ap¬ 
propriated for any purpose, to take 
out and completely remove the 
affected part, substituting in its 
place a piece of sound wood. 
Again, the damage done by the 
breaking of a branch from a tree is 
often very serious, as illustrated in 
Fig. 13. The wound was of very 
old standing, and entirely healed 
over, but the decay had never¬ 
theless made steady progress. It 
was found, by counting the con¬ 
centric layers, that the branch was 
broken when the tree was fifty-six 
years old; that in twenty-three 
years more the annual layers had 
completely covered the broken 
part, while outside this twenty- 
third layer there were twenty-seven 
years’ growth of duramen or heart- 
wood, and twenty-six years’ growth 
of alburnum or sap, the tree having 
been about 132 years old at the 
time of its being felled. 
Pruning closely, except in the case of very young 
trees, where the branches are small, and the wound is 
certain to be soon healed over, will, as before shown, 
fig. 14. 
