TSUGA MERTENSIANA, (Bong.) Sarg. 



TSUGA PATTONIANA, (Jeffr.) Eng. 

 Mountain Hemlock. Black Hemlock. 



Size. Average 25 to 60 ft. by 1 to 2 ft. Maximum, 125 ft. by 3 ft. 



Growth. Slow but persistent. Trees 18 to 20 inches in diameter 

 are 180 to 260 years old. 



Root System. Shallow, tracing. 



Bole. Tapering; base often buttressed. 



Crown. Little resemblance to other hemlocks. Narrowly pyrami- 

 dal, generally extending nearly to the ground. 



Tolerance. Very tolerant, equal to western hemlock and sur- 

 passing all its associates. Even dense stands clear very slowly. 



Wood. Pale red, fine grained, soft, not strong; 32 pounds. 

 Lighter than western hemlock. 



Reproduction. Prolific seeder from the 20th year; some seed each 

 year and frequently heavy seed years. Flowers in May; cones mature 

 and shed seed in September and October, and the cones fall during the 

 winter. Seed small, light, large winged; germination percent medium; 

 vitality transient. Seed beds, both mineral and humus soils suitable; 

 seedlings stand much shade and prefer some, but do not thrive under the 

 dense shade of their parents. 



Range. Pacific cpast mountains of Alaska southward through 

 the high Sierras of California and to northern Idaho and Montana. 

 Mainly at timber line, but in far north at sea-level. 



Climate. Severe alpine climate. Precipitation generally abun- 

 dant; transpiration generally rapid. 



Soil. Generally inhabits loose, coarse, moist soils of mountains. 



Association. Occurs in limited pure stands and in mixture; in the 

 north with Sitka spruce, western hemlock and alpine fir; southwards at 

 high altitudes with white bark pine, alpine fir, Lyall larch, and Engel- 

 mann spruce; in southern B.C. with yellow cedar, amabilis fir, and alpine 

 fir. 



General. Its commercial importance is small as yet, because of its 

 small size and inaccessibility. It may be valuable for pulp in the future. 



PSEUDOTSUGA TAXIFOLIA, (Poir.) Britt. 



PSEUDOTSUGA MUCRONATA, (Raf.) Sudw. 

 Douglas Fir. Red Fir. Yellow Fir. Douglas Spruce. 



Size. Largest tree of America except the Sequoias. Coast average 

 150 ft. by 3 ft. Maximum 250 ft. by 10 ft. Mountain average, 100 ft. 

 by 2 ft. 



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