20 TIMBER AND TIMBER TREES. [CHAP. 



magnitude that logs should not be taken of dimensions 

 much in excess of the specification given, but correspond- 

 ing as nearly as possible in size to it, as the removal of 

 more than a few of the outer layers of heart-wood is 

 likely to involve a serious loss of strength. 



It should be observed that a tree does not cease 

 growing when it arrives at maturity. As long as it is 

 alive, it continues to increase in bulk by the addition of 

 the annual layer ; but when maturity is once passed, each 

 succeeding year produces a certain amount of deteriora- 

 tion at the centre. This deterioration or decay appears 

 in various stages, and generally exhibits, in the first 

 instance, either a white or yellowish-red colour at the 

 butt or root end of the stem. If white, the defect is pro- 

 bably very slight, and does not usually extend more 

 than a few feet up ; but if yellowish-red in colour, it is 

 not unfrequently of a more serious character. Again, if 

 the affected parts have assumed a decidedly red tinge, 

 the tree is said to be, in technical language, " foxy," 

 and is scarcely fit for constructive purposes, as the decay 

 will be found to pervade a great portion of the tree. 

 The further advanced stage of deterioration is that 

 which may be described as a drying up or wasting away 

 of the wood immediately surrounding the pith, or medulla. 

 It forms a hollow, first at the butt, and then spreads 

 upwards, gradually increasing in size as the tree gets 

 older, while the defect may eventually reach even into 

 the branches. 



Trees are of course most valuable, as yielding the 

 largest possible amount of good timber, just prior to the 

 commencement of this change, which is indicated almost 

 immediately it takes place by the topmost branches and 

 branchlets becoming stunted and thick ; being, in fact, 

 what the surveyor or woodman would call "stag- 



