240 



FOREST TREES OF THE PACIFIC SLOPE. 



The color of the bark, which is prevailingly whitish, is sometimes varied with 

 very pale green or yellowish areas. The leaves (figs. 103 to 105) are smooth 

 on both surfaces at maturity, somewhat shiny, and deep yellow-green above and 

 much paler beneath. Leaf stems, yellow and flattened near the leaf blade, vary 

 in length from about li to nearly 3 inches. In autumn the leaves become a 

 clear lemon-yellow. Mature twigs are smooth, shiny, clear reddish brown, with 

 similarly colored thinly resinous buds. 



Wood : Silvery white sapwood forms a large proportion of the stem ; the small 

 core of heartwood is pale brown. The wood; rather fine-grained, is light, exceed- 

 ingly soft, brittle, not durable in contact with the ground. Owing to its phys- 



Fig. 103. — Populus tre m al o ides, eastern form. 



ical fitness and the white color of its wood it is much in demand in the East 

 for paper pulp, while its freedom from odor has made it very useful in its west- 

 ern range for fruit-box boards, into which large quantities of fire-killed trees 

 are cut. Green timber is not used for the latter purpose because it warps and 

 checks. 



Longevity. — Not fully determined. Evidently a short-lived tree. Trees from 

 10 to 14 inches in diameter are from 21 to 36 years old. 



Southern Labrador to Hudson Bay (southern shores) and northwest to Mackenzie 

 River (near mouth) and Alaska (Yukon Valley) ; south to New Jersey, Tennessee, 



