THE CHARACTERS OF TIMBER 



115 



in a bat. They are, as a rule, put down to the borings of an 



insect, but a little trouble has enabled one, in some cases at least, 



to trace their origin to an incompletely healed 



wound (see figure 113). It still remains to be 



determined whether such wounds are due to a 



splitting of the bark through its whole thickness, 



caused by the rapid growth of the wood, or whether 



we must seek for some other explanation. We 



shall have occasion to speak again of wounds when 



discussing grafting in Part II, but it may here be 



said that a wound may persist for many years. 



Evidence of injury can sometimes be traced through 



the woody rings of a century or more, while a 



distinct scar is still evident on the bark. 



A very striking series of specimens may with a 



-,.,,! ',! , ,, .,-, , FIGURE 113. A sec- 



little trouble be got together to illustrate, not only tion through a 



the rapid healing of wounds made intentionally, 



though with care, but also the harmful effects upon 



trees which often result from such as are made casually or which do 



not quickly close. 



