CHAPTER IV. 

 ON THE DEFECTS FOUND IN TREES. 



Having referred to a few characteristics of growing 

 timber trees, it will perhaps be interesting if, before pro- 

 ceeding to a detailed account of the various kinds, we 

 give a description of some of the defects to which trees 

 are liable prior to their being felled and hewn, or other- 

 wise 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. In typical heart-shake, we find the 

 central parts of the stem show signs of hollowness, with 

 radiating cracks around running more or less out into 

 the younger layers ; the widest part of the crack is nearest 

 the centre of the stem, and this does not necessarily 

 show obvious signs of rot or decay. 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 



