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- 
