212 TIMBER AND SOME OF ITS DISEASES. [CHAP. 



remains of the proximal parts of the dead branches 

 are sticking out from the trunk like unsightly wooden 

 horns. Some of these branches may have been broken 

 off by the fall of neighbouring trees or large limbs ; 

 others may have been broken by the weight of snow 





FIG. 27. Portion of a tree from which a branch has been cut off close to the stem. 

 (7, the cambium of the branch ; , its cortex. 



accumulating during the winter ; others again, may 

 have been broken by hand, or by heavy wind ; and 

 yet others have died off, in the first place because the 

 overbearing shade of the surrounding trees cut off the 

 access of light to their leaves, and secondly because 

 the flow of nutritive materials to them ceased, being 

 diverted into more profitable channels by the flourish- 



