36 



trunk or larger limbs at the point where a branch left them. He had 

 had much to do with sawmills, and had seen many such sections cut, 

 and often one tree, falling beneath his axe, had lighted in the fork of 

 another and split it to the ground. The appearance then presented was 

 that presented by the forked twig which a schoolboy split to make his 

 bird trap. 



The wood from bark to bark formed one continued strip of 

 white, from which the white wood of the branch turned off without 

 mark of junction, just as rivers were indicated in a map. These are 

 normal branches. Sometimes, however, a very different appearance 

 presented itself — a branch was apparently inserted into the trunk, 

 penetrating only through the outer rings, and surrounded by a kind of 

 socket. Such limbs had commenced their growth after the branches 

 above them, and, though produced late in life, had outstripped their 

 predecessors, partly because nearer the roots, and partly because they 

 had been deriving their nourishment from the outer and softer layers 

 of the cambium region, where alone the sap descended in any con- 

 siderable quantity. It was only of the normal limbs that he should 

 speak for the present. 



A well formed tree, then, consisted of a trunk or trunks, ascending 

 to a certain distance and there throwing off one or more limbs. These 

 limbs might be large or small in comparison with the parent stem, 

 might be opposite or slightly separated, and might turn off at any 

 angle not exceeding 90°, Where the limb turned off the stem was 

 deflected in the opposite direction. That deflection might be very 

 slight, but it could always be traced and sometimes was so great as to 

 render it impossible to tell which of the two or more divisions was to 

 be regarded as the continuation of the parent stem. The original 

 pattern thus given was aftenvards adhered to, and throughout the 

 whole structure each branch with its branchlets repeated the same 

 form of subdivision, so that it m.ight be traced to the minutest ramifi- 

 cations, and could be seen in the skeleton of the leaves. If, then, we 

 rightly understood one forking, we understood all, and he proposed to 

 consider one minutely. There were several points requiring attention, 

 which might be enumerated as follows : — 



1. The size of the limb {i.e., its sectional area). 



2. The size of the stem above the joint. 



3. The angle at which ihe limb branches off. 



4. The amount of deflection in the stem. 



5. The relative length of the previous and succeeding intemodes. 



i 



