IMPORTANT LOCAL PLANTING. 101 



The vertical or top growth of a tree being found, 

 an acre or forest can very easily be ascertained by 

 the eye of the practical forester, and reduced to 

 authentic figures by a very simple process of arith- 

 metic. And it would be well if all other figures re- 

 lating to forestry and tree culture were as much to be 

 relied upon. 



The tree, however, not only increases in length, but 

 also in thickness ; and while ninety-nine persons out 

 of every hundred wiU tell at sight how much a tree 

 is annually making in height, probably not over one 

 in a hundred will be able to say (even approximately) 

 how much the tree is increasing in thickness or 

 girth. The following is our method of doing it, and 

 practice alone perfects the process : Take a tree 48 

 feet high, equal to 5 7 6 inches, and if a pine or fir, and 

 proportionally grown, it will be 48 inches girth at 

 base, or 24 inches at the centre; therefore multiply 

 the length, 576, by the girth, 24, and 13,824 super- 

 ficial inches are the result. Now, if the layer of wood 

 were an inch thick, the figures 13,824 would just 

 remain as they are ; but if, instead of the zone or layer 

 being 1 inch thick, it is only one-eighth of an inch — 

 which I consider the proper thickness for the tree to 

 make if proportionally and well grown — therefore, 

 instead of multiplying, we require to divide, and ac- 

 cording as the zone or layer is thick or thin, so will 

 the quotient be. 



Assuming, therefore, that such a tree is making 

 woody layers one-eighth thick, the tree is thereby mak- 

 ing 1 cubic foot of timber annually. Taking the same 

 size of tree, however, and making not one-eighth thick- 

 ness of layer of wood, but only one-twelfth yearly — 

 therefore, instead of making 1 cubic foot, it is making 



