Page:Timber and Timber Trees, Native and Foreign.djvu/46

 CHAPTER IV.

ON THE DEFECTS FOUND IN TREES.

described the characteristic points of growing timber trees, it will perhaps be interesting if, before proceeding to a detailed account of the various kinds, we were to give a description of some of the defects to which trees are liable prior to their being felled and hewn, or otherwise prepared for the market.

There is one defect so common to nearly all trees, that I will treat of it first. It is known to carpenters as the heart-shake. It is met with to a greater or lesser extent in nearly every species of timber that we have to deal with, and as it has a very important bearing upon the value of the tree affected, we cannot afford to disregard it, inasmuch as the quantity of good and serviceable material obtainable from a log, depends almost entirely upon the distance we are constrained to go from the pith, or centre, in order to get clear of it. Experience has shown that among the woods least affected by the heart-shake are African Oak, or Teak, as it is sometimes called; Sabicu; Cuba Mahogany; and English Elm; while Indian Teak and Australian Tewart have it in