PINACEAE 



Western Hemlock 



Tsuga heterophylla (Rafn.) Sarg. 



HABIT. A tree 125-175 feet high and 2-4 feet in diameter 

 (max. 259 by 9 feet); tall, clear truck; short, open, pyramidal 

 crown with typically flexible drooping terminal leader. 



LEAVES. Flattened; 14 -% inch long; dark, shiny green and 

 grooved above, 2 broad bands of stomata below; abrupt, slen- 

 der petiole; mostly 2-ranked; rounded or blunt at apex. 



FLOWERS. Male yellow; female red or purple with rounded 

 bracts shorter than scales. 



FRUIT. %-l inch long, ovoid, light brown, scales sub- 

 orbicular, wavy-margined. Seed: \{^ inch long; ovoid; Yi as 

 long as narrow, straw-colored wing. 



TWIGS. Slender; pubescent for 5-6 years; pale yellow- 

 brown becoming dark red-brown; drooping. Winter buds: 

 ovoid, }^6 inch long, blunt, bright chestnut-brown. 



BARK. Thin {l-lYz inches) even on largest trees; young 

 bark scaly, russet-brown; on old trunks hard, dark russet-brown 

 with furrows separating wide flat ridges; inner bark dark red 

 streaked with purple; used for its tannin content, 



WOOD. Superior in quality to eastern hemlock; one of 4 

 major timber-producing species of Pacific Northwest; uniform 

 texture and not very harsh or splintery; suitable for all uses 

 but heavy construction, and most important pulpwood species 

 of region. 



SILVICAL CHARACTERS. Tolerant throughout life; 

 growth rapid, comparing favorably with Douglas-fir, seldom 

 attaining age of over 500 years; reproduction very abundant 

 and vigorous; shallow, wide-spreading root system; susceptible 

 to fire injury, and butt rot common in old trees. 



HABITAT. Transition and Canadian zones; altitudinal 

 range from sea level to 7,000 feet; prefers deep, moist, porous 

 soils, but hardy in drier situations; in pure, dense stands or 

 mixed at lower levels with Douglas-fir, silver and grand firs, 

 giant arborvitae, redwood, and hardwoods; and at higher levels 

 with noble fir, Alaska cedar, mountain hemlock, western white 

 and lodgepole pines. 



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