Growth. Rapid and persistent. Southern British Columbia 

 studies of 184, 571, 159 and 141 trees showed that 10 inch trees were 

 grown in from 44 to 66 years, 20 inch in from 90 to 124 years, and 30 inch 

 in from 157 to 215 years. Life over 500 years. 



Root System. Heart. 



Bole. Cylindrical, straight, and clear for 50 to 100 feet. 



Crown. Pyramidal when young; rounded and flattened when old. 



Tolerance. Moderately tolerant becoming less so with age. More 

 tolerant than white and lodgepole pine and less so than Engelmann 

 spruce. 



Wood. Moderately heavy; fine textured; hard, strong, and 

 durable; 29 pounds. 



Reproduction. A prolific seeder with heavy seedings at intervals 

 of 3 or 4 years. Cones ripen early in August and shed seed in September 

 and October. Germination percent moderate and vitality persistent. 

 Germinates best on warm, moist mineral soil and also on intermixed 

 humus. On the coast reproduces best on burned over areas. 



Range. Western North America, from central British Columbia 

 southward to central California, to northwest Texas, southern New 

 Mexico, Arizona, and northern Mexico. In Canada from the eastern 

 foothills to the coast, north to lat. 55, Skeena River. Optimum, coast 

 of southern British Columbia. Sea-level to 6000 feet in British Colum- 

 bia. 



Climate. Widely variable with range Temperature generally 

 mild. Precipitation from less than 15 inches to over 100 inches. Humid- 

 ity varies from dry interior to moist coast. Prefers north exposures 

 except at northern limit. 



Soil. Adapted to a wide range of soils. Avoids saturated, poorly 

 drained, heavy soils. Moisture conditions more important than the soil. 



Association. Often forms large pure forests, but generally is 

 associated with various other species of different habits; in Canada 

 chiefly with western hemlock, western red cedar, Sitka spruce, lowland 

 fir, western white pine, western larch, and lodgepole pine. 



General. Commercial importance very great. In the Canadian 

 cut of 1912, it ranked third with about 20% of the total at $12.33 per 

 thousand ($15.45 in 1910). It bids fair soon to oust white pine from 

 second place. In the United States, Douglas fir is estimated at 525 

 billion feet or 21% of the total stumpage. This is nearly twice greater 

 than the next greatest single species (western yellow pine, 275 billion), 

 and equals the combined stumpage of the southern hard pines (350 

 billion), and the white and red pine (75 billion). It is greater than the 



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