268 FOEEST TEEES OF THE PACIFIC SLOPE. 



OCCURRENCE. 



Characteristic on heads of mountain streams, springy and boggy slopes, gulches, bor- 

 ders of high meadows and lakes, in wet, mucky, but usually rocky soils ; abundant water 

 (saturation) in soil essential. 



Forms large, dense, pure thickets with adjacent lodgepole pine, mountain and vine 

 maples, black Cottonwood, willows, and aspen. 



Climatic Conditions. — Similar to those of lodgepole pine (at high elevations). 



Tolerance. — Appears to endure much shade in seedling stages, but seeks full top 

 light later ; probably less tolerant than red and Sitka alders. 



Reproduction. — Plentiful annual seeder. Seedlings rather abundant in wet or moist 

 muck and litter, in shade or in open. 



Red Alder. 



Alnus oregona Nuttall. 



DISTINGUISHING CHARACTERISTICS. 



Red alder is one of the two largest Pacific alders ; it reaches a height of 

 from GO to 90 feet, and a diameter of 18 to 30 inches — occasionally a little 

 larger ; usually 35 or 40 feet high and from 10 to 15 inches through. The trunks 

 are straight, giving off rather slim branches which droop in a narrow, long, 

 dome-like crown. The thin-barked, smooth-looking, light ashy gray and whitish 

 trunks are clear of branches for one-half or two-thirds their height. Large 

 trunks have distinctly but very shallowy seamed bark, the thin ridges being flat, 

 narrow, and occasionally connected by smaller side ridges. Season's twigs 

 are clear, shiny, mahogany-red. with numerous light-colored dots, and are 

 sometimes slightly or considerably hairy, especially toward their ends ; deep 

 red buds covered with a light-colored scale-like down. Mature leaves (fig. 118) 

 are smooth and deep yellow-green above, sometimes with minute sparse, white 

 hairs ; paler beneath and coated with very short, rust-colored hairs — often heavi- 

 est on the yellowish veins ; large leaves of vigorous shoots are least hairy. 

 Ordinarily leaves are about 3 to 5i inches long, but are from 6 to 10 inches on 

 strong shoots. The toothed borders of the leaves are very slightly curled 

 toward the under surface. Tassel-like male flower clusters are from 5 to 6 

 inches long, and about one-fourth inch thick. Mature cones (fig. 118), which 

 shed their seed in autumn, vary in length from about one-half inch to 1 inch ; 

 seeds (fig. 118, a) have very narrow, thin, wing-like margins. Ends of cone- 

 scales, very thick and blunt — squarish. Wood, pale reddish-brown, brittle, and 

 light when dry ; newly cut the surface of the whitish sapwood soon becomes 

 stained a red-brown. One of two Pacific alders which are large enough to 

 furnish saw timber. The cherry-like, fine grain is attractive when finished, 

 making the wood suitable for cabinetwork, for which it is used to some extent. 



Longevity. — Not fully determined. Grows rapidly during first 20 or 30 years. 

 Trees from 10 to 18 inches in diameter are from 28 to 55 years old. 



RANGE. 



From Sitka, Alaska, through islands and coast ranges of British Columbia, western 

 Washington, and Oregon to California (coast ranges to Santa Inez Mountains, near 

 Santa Barbara). - 



OCCURRENCE. 



Borders of streams and adjacent moist bottoms, benches, and gentle slopes ; in fairly 

 well-drained, rich, humous, rocky, or gravelly soils. Largest in Puget Sound country. 

 Abundant soil moisture and rich soil requisite for best growth. 



In extensive belts (at north), patches, and lines of pure growth, or sometimes mingled 

 with Nuttall and other willows, black cottonwood, grand fir, broadleaf and vine maples, 

 and western dogwood. 



