134 PROPERTIES OF WOOD. 



to a certain distance near the ground ; the age of the base 

 of the tree, where the verticils are obliterated by the bark, 

 can easily be estimated. The true base of the year's shoot, 

 where the pith divides, is in young stems higher and in old 

 stems lower (on account of the obliquely ascending branches) 

 than the apparent external position of the verticils : cf. Fig. 51, 

 where M is the pith ; after the wood has thickened up 

 to 4, the external position of the verticil is above the true 

 base of the leading shoot. In most broadleaved trees, except 



M 



Fig. 51. Longitudinal section through a coniferous stem and branch. M, pith. 

 The darker the branch-wood the more rotten it is. 



in cherry, the branches of which are sub-verticillate like those 

 of a silver-fir, the ramification is irregular and usually the 

 age can be determined only by counting the annual rings. 



The annual zones of wood that thicken the stem and 

 branch are firmly connected until the branch dies, as those 

 at the base of the branch bend and unite at one end with the 

 vertical zones of the stem, and at the other end with the 

 obliquely ascending or horizontal zones of the branch 

 (Figs. 51 53). The thicker the branch becomes, the more 

 the stem-fibres are curved and the greater the disturbance 



