Range. Coast ranges from southern Alaska to southern California, 

 also in northern Idaho and Montana. Probably extends southward into 

 the interior of B.C. Generally a tree of low elevations. 



Climate. Optimum in great humidity and precipitation. 



Soil. Moist river bottoms. Mesophytic. 



Associations. Limited forests of pure growth. Occurs in mix- 

 ture with various conifers. 



General. Of medium commercial importance in B.C., where it is 

 largely used for pulp. 



POPULUS DELTOIDES, Marsh. 

 Cottonwood. 



Size. Average 75 to 100 ft. by 2 ft. Maximum 125 ft. by 5 ft. 



Growth. Rapid but only briefly sustained. 



Root System. Tap root with strong laterals. 



Bole. Short, medium taper. 



Crown. Moderately spreading. 



Tolerance. Intolerant. 



Wood. Light, weak, not durable; 24 pounds. 



Reproduction. Prolific annual seeder; flowers in April and May, 

 and sheds seeds in early summer. Seed small, light, tufted. Germina- 

 tion percent medium; vitality transient. 



Range. Quebec to southern Alberta, south to New Mexico and 

 Florida Low to medium altitudes. 



Soil. Inhabits light, well drained soils. Xerophytic to mesophytic. 



Association. Occurs individually and grouped with sycamore, 

 hackberry, aspen, box-elder, green ash, elms, and Balm of Gilead. 



General. Commercial importance very small in Canada. Adapted 

 to farmers' woodlots on account of its rapid growth and ability to 

 reproduce by suckers. 



BETULA, The Birches. 



Size. Many are shrubs or small trees; a few are medium-sized 

 trees. 



Growth. Rapid but not persistent; short lived. 



Tolerance. Intolerant in Canada as a rule. Betula lutea is 

 moderately tolerant. 



Wood. Fine texture, dense, quite heavy, hard, strong, perishable. 



Reproduction. Prolific seeders; flower in spring before or with the 

 leaves. The aments mature and fall to pieces in late spring or early 

 summer. Seed very light and winged; germination percent medium; 



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