100 FAMILIAR TREES 
a height of 300 feet, and a diameter of from six to 
twelve or, it is stated, even twenty feet. In these 
plains the stems are free from branches for more than 
200 feet from the ground ; and their canopy of foliage 
is so dense overhead as completely to shut out the 
light of the sun. On the steep slopes of the mountain 
cafons, on the other hand, trees often stand alone, 
and are clothed with branches from base to sumunit. 
On the Californian Sierras it seldom grows at an alti- 
tude of more than 5,000 or 6,000 feet above sea- 
level; but in Northern Arizona it forms forests at a 
level of between 8,000 and 9,000 feet ; and in Colorado 
it even extends to an elevation of 11,000 feet. At all 
these high levels, however, it attains dimensions far 
less than those it reaches in the plains, and at its 
highest vertical limit it is but a low shrub. The 
“ Douglas Fir” and “ Douglas Spruce” are the names 
most commonly applied to it in the European 
pinetum ; but “ Oregon Pine” is the name by which 
the timber is chiefly known in our market, though it 
was at one time known as the “Nootka Fir.” In the 
Uintah Mountains it is known as “Swamp Pine” and 
“ Bear River Pine,” while such misleading appellations 
as “Western Pitch Pine” and “Hemlock” are natura] 
to the non-botanical pioneer who sees slight resem- 
blances. “Black Fir” or “Black Spruce” refers pro- 
bably to the dark green of the foliage; but “Red 
Fir” and “Yellow Fir” seem to belong to different 
varieties of the wood, the produce most probably of 
different conditions of growth. 
The sapwood is generally narrow and yellowish ; 
but the heart is sometimes also yellow, fine-grained 
