PINE TREES OF ROCKY MOUNTAIN REGION. 5 
ties of the western white pine, Pinus monticola minima and P. monti- 
cola digitata, based on differences he recognized in the form and size 
of the cones. A purple-coned form of western white pine cultivated | 
in England was described in 1866 as Pinus porphyrocarpa A. Murray, 
and later, in 1892, as Pinus monticola variety porphyrocarpa Masters. 
Tn the writer’s judgment, none of these forms are worthy of specific 
or varietal distinction.* 
DISTINGUISHING CHARACTERISTICS. 
In dense forests, where its most characteristic form is found, this 
pine has a tall, slender shaft, with a peculiarly short-branched, nar- 
row, symmetrical crown. The branches are usually slender and 
drooping, and in early life extend over one-half or two-thirds the 
length of the trunk. Its height ranges from 90 to 150 feet, and its 
diameter from 24 to 5, or exceptionally, from 6 to 8 feet. In open 
forests, where the conditions of growth are less favorable to its better 
development, western white pine is a short-bodied tree, 50 or 60 feet 
in height, with one or more very long, stout, horizontal branches ex-. 
tending from 10 to 15 feet or more beyond the other slender branches. 
This striking characteristic distinguishes the tree as far as it can 
be seen. 
The bark of trees a foot or more in diameter is distinctly broken 
into small, square blocks. No other tree associated with it has this 
bark characteristic. The bark of mature trees is rarely over 14 inches 
thick. In dense stands the color of the bark is grayish purple, while 
in open, windswept stands it is a distinct cinnamon-brown. The 
fierce winds of such locations constantly tear off the thin outer scales 
of bark and expose the red-brown interior. Young trees have thin, 
smooth, bright gray bark, as do also the branches and upper stems 
of old trees. The scaly winter buds are about one-half an inch long. 
During the first year the young twigs are deep yellowish brown and 
minutely hairy, but during the second year they become smooth. 
The foliage of this pine is bluish green with a whitish tinge. That 
produced each season remains on the twigs until the third or fourth 
year. The leaves are from 2 to about 4 inches long and are borne 
in bundles of 5 (Pl. I, a; Pl. 11). Their margins have minute widely 
separated teeth. The foliage of trees grown in exposed situations is 
1 Western white pine was introduced into England by David Douglas shortly after he 
discovered it in 1831. According to Elwes and Henry (Trees of Great Britain and Ire- 
land, V, 1024, 1910) it was not common in cultivation there until 1851 or 1855. While 
perfectly hardy in England as regards cold, these authors find that it grows best in 
Scotland, particularly in moister situations. The largest trees planted in Hngland are 
from 76 to 81 feet in height and from 20 to 32 inches in diameter. Some of these trees 
were planted as early as 1834 and 1847. Pinus monticola thrives in northeastern United 
States, where it has been planted as far north as western New York (Wyoming County) 
and eastern Massachusetts. 
