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JOURNAL OF FORESTRY 



sentative of the 50-year-old timber in different kinds of stands were 

 remeasured and four years' growth figured. This growth, which is 

 the first actually obtained by measurements of standing timber in this 

 region, is shown in a condensed form in the following table : 



Grozvth of Western White Pine and Associated Species 



The most significant thing brought out by these figures is the remark- 

 able growth of the white pine, which in this instance adds 1,095 board 

 feet per acre each year. This is followed closely by Douglas fir with 

 a growth of 879 board feet and yellow pine with 745 board feet. In 

 this region the precipitation is about 30 inches, which is about the aver- 

 age for the Idaho white pine region. 



The data show an actual increase of 9.1 per cent for the white pine, 

 7.2 per cent for the yellow pine, 11.9 for the Douglas fir, and 5.6 per 

 cent for the larch, and this is their present annual increase in value. 

 The larch is not representative of the best growth of this species, for 

 the soil on this plot was rather poor. 



J. A. Larsen. 



Indian Forester, March, 1918, pp. 138-140, brings the following de- 

 tails about Balsa wood (Ochroma lagopus), which should prove of 

 interest to American foresters, since the tree grows freely in the Cen- 

 tral American States: 



The structure of the wood is altogether special ; it is composed of 

 very thin-walled cells of barrel shape, which interlace with each other 

 and contain scarcely any woody fiber ; these cells are filled with air, 

 and hence are derived both the extreme lightness of the wood and its 

 property of non-conductivity of heat. Its weight, when thoroughly 

 dried, is 7.3 pounds per cubic foot, cork, which stands next in lightness, 

 weighing 13.7 pounds per cubic foot. It is not easily obtained in a dry 

 condition, however, and therefore, as obtained commercially, it will be 

 found to weigh from 8 to 13 pounds. And though so light, it has re- 



