SYLV1CULTURAL NOTES ON DOUGLAS FIK. 319 



b. Shape and Development. 



The Douglas Fir develops a straight undivided stem, 

 except that in some localities the first 6 feet from the 

 ground are curved. Grown in the open the crown 

 covers the whole stem and comes down almost to the 

 ground; the stem of such trees is very tapering. 

 If grown in crowded woods in its natural home, 

 the lowest portion of the stem is exceptionally stout; 

 the crown forms a sharp cone confined to the upper 

 half of the stem, whilst the bole is described as of a 

 remarkably cylindrical shape, at least as much as that 

 of the European Silver Fir. A regular wood * which 

 the author has seen was 32 years old ; in this all the 

 trees were excessively tapering, giving a form figure of 

 39 f for timber only (over 3" diameter at the thin 

 end). Further experience may show that the trees with 

 advancing age adopt a more cylindrical shape. 



The growth of the Douglas Fir is exceedingly fast. 

 At the same time it varies enormously according to 

 climate and soil. According to Mayr, a wood 80 years 

 old and grown under the most favourable conditions 

 showed an average height of about 133 feet, or an 

 average annual height-growth of nearly 20 inches. The 

 Taymount plantation shows an average height-growth 

 of about 22 inches. 



In Montana, according to Mayr, the Douglas Fir shows 



* Taymount, on the estate of the Earl of Mansfield, Scotland ; area = 8 acres ; 

 total age of trees = 32 years in 1888 ; number of trees per acre = 202 ; sectional 

 area of trees at 4' 6" = 158'17 square feet ; average height = 60 feet ; volume 

 = 3738 cubic feet of timber. 



f Under form figure is here understood the proportion of the actual volume 

 of the stem to a cylinder of equal height and equal cross section at 1' 6" from 

 the ground. 



