FOREST TREES OF THE PACIFIC SLOPE. Ill 



The detailed range of alpine fir in the Rocky Mountain region will be dealt 

 with in a later bulletin. 



OCCURRENCE. 



In cool, moist, and, in part, subalpine situations; commonly on slopes at timber line, 

 and at its lower limits in protected valleys, at heads of streams, and about mountain 

 lakes and meadows. Best growth on fairly deep, loose, moist soil ; will grow also in 

 wet and on poorest and driest thin soils. Main occurrence limited by requirement of 

 soil moisture to elevations where snowfall is great. Requires less soil moisture in 

 general than Engelmann spruce, but grows in places too wet for the spruce, as well 

 as on Douglas fir soils, where spruce will not succeed. Does not thrive on heavy, 

 clayey soils. Altitudinal occurrence in Alaska narrow, owing to low timber line; more 

 abundant on east than on west slopes of Alaskan coast mountains. Throughout north 

 coast ranges and the Rocky Mountains the vertical ran^e is wide. Here on all slopes, 

 but largest on high north aspects. At south, altitudinal extent is again narrow, because 

 favorable moisture occurs only at much higher elevations. 



In pure, small stands and in mixture. In Alaska, mainly with black hemlock ; at 

 higher levels in Washington, with black hemlock, occasionally yellow cedar and white- 

 bark pine, and lower, with noble and amabilis firs; in Oregon, with black hemlock, 

 Engelmann spruce, western white pine, lodgepole pine, and noble fir. 



Climatic Conditions. — Endures rigorous climate, and therefore it goes farther north 

 than any other coast fir. At far north, subject to blighting winter winds, weak insola- 

 tion due to high latitude and extreme cloudiness, excessive precipitation, averaging over 

 60 inches of rain and from 2 to 5 feet of snow, and also to minimum temperature 

 <it about —40° E. At south, sunlight is more abundant, lower humidity and smaller 

 precipitation — averaging about 25 inches and mainly snow. Maximum temperature, about 

 90" E. 



TOLERANCE. — Only slightly less tolerant of shade than Engelmann spruce, and more 

 so than other associated species (except black hemlock) ; maintains long-suppressed 

 reproduction under heavy shade, and with admission of light recovery and growth are 

 rapid. 



Reproduction, — Moderately prolific seeder. Seed with rather high rate of germina- 

 tion, but of transient vitality. It begins to bear cones as early as the twentieth year. 

 Produces some seed locally every year, with heavy production at intervals of about three 

 years. Over large areas, however, cones often fail to mature during some seasons. 

 Reproduction usually abundant, both in open on exposed mineral soil, and on thin and 

 heavy moist duff under light or heavy shade. .Seedlings grow most thickly on north 

 sides of groups or forests and under branches of mother trees ; small shaded openings 

 among seed trees nearly always show reproduction. Occasionally at high elevations 

 branches lying on ground take root (layer), from which, however, reproduction is 

 probably rare. 



Grand Fir; White Fir. 

 Abies grandis Lindley. 



DISTINGUISHING CHARACTERISTICS. 



Grand fir is commonly called "white" fir because of its conspicuously whitish, 

 smooth hark. Other firs of the same region are known as " white " firs of a 

 "different variety," especially Abies concolor, to which the name "white fir" 

 appears to belong more fitly than to any other. It is desirable, therefore, for 

 the sake of a distinctive common name, to coin for Abies uiunxlis the name of 

 "grand lir." which is appropriate, since it is a very stately and grand tree when 

 fully matured. It grows to a height, in such favorable situations as bottomlands, 

 of from 150 to 200 and, exceptionally. 250 to 275 feet, with a diameter of from 

 3 to 4 feet. On the less favorable hill lands its greatest height is from SO to 

 125 feet, with a diameter of from IS to 30 inches. Its trunks are remarkably 

 straight and very gradually tapered. Standing alone or in ;m open forest, it 

 carries its crown branches to within a few feet of the ground even when old, 

 hut in a close stand the crown covers only one-half or one-third of the stem. 

 The crown is a narrow, rather open cone, pointed in young trees, hut in old age 

 is somewhat rounded at the top, and often, from the strong drooping of the 

 lower branches, appears wider in the middle. The rounded top results from 



