Page:Timber and Timber Trees, Native and Foreign.djvu/57

VI.] 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 appropriated 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 nevertheless made steady progress. It was found, by counting the concentric 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,