32 BULLETIN 327, U. S. DEPARTMENT OF AGRICULTURE. 
yellowish-brown to very light brown. The wood of this fir is little 
known in the Rocky Mountains and is only occasionally cut for lum- 
ber in the Pacific slope region, though its good quality entitles it to 
be better known and more widely used. The ease with which the 
wood can be worked, and other good physical qualities, render it the 
equal, if not the superior, of the softer fir woods now cut for lumber. 
OCCURRENCE AND HABITS. 
Grand fir is essentially a tree of moist situations. It grows most 
commonly on alluvial stream bottoms and adjacent higher ground, 
lower gentle mountain slopes, depressions, and gulches, at elevations 
between about 2,000 and 7,000 feet (Map No. 8). The best and most 
abundant growth occurs on stream bottoms at the lower levels, much 
smaller trees being found at high elevations. Its deep root system 
demands permeable, preferably moist, porous, well-drained soils. 
With favorable moisture and climatic conditions grand fir grows 
well on rather poor, thin soils, but better quality is necessary in soils 
deficient in moisture and subject to rapid evaporation. 
Grand fir rarely occurs in pure stands, except of limited extent. 
Usually it is mixed with western white pine, lodgepole pine, western 
larch, Engelmann spruce, mountain red cedar, western yew, Douglas 
fir, black cottonwood, balm of Gilead, and sometimes with western 
yellow pine. The number of species and the percentages of the stand 
they represent in this association vary greatly in different localities 
within the general range of grand fir. It is always dominant when 
associated with mountain red cedar. 
Grand fir is the least tolerant of shade, with one or two exceptions, 
of all of our fir trees, growing only moderately well under such condi- 
tions. It is much less able to live under the shade of other trees than 
the mountain red cedar, western hemlock, and western yew, but much 
more tolerant than Douglas fir, western white pine, western larch, 
and western yellow pine. Seedlings endure considerable shade for 
several years, but unless they are given full overhead light, such 
growths become dwarfed and die within a few years. With overhead 
light, the height growth of this fir is rapid, and under side shade the 
trunks are readily cleared of branches, forming the characteristic 
long, clean stems. Endurance of shade, however, varies in general 
with age, exposure, moisture of the soil and air, quality and quantity 
of available soil, altitude, and latitude. The largest trees are prod- 
ucts of sufficient moisture, soil, heat, and full sunlight. Under these 
conditions it will also endure considerable shade. On poor, dry 
soils and in warm exposed places, shelter from cold winds and some 
shade are beneficial in reducing soil evaporation and transpiration; 
