AMERICAN FOREST TREES 705 



too slow growth to tempt the forester. A century is required to pro- 

 duce a fence post, and 200 years for a crosstie. Forest fires do little 

 injury, for the ground is generally so bare that fire dies out of its own 

 accord in a short distance. The tree can never be planted much for 

 ornament. Even if it would grow outside of its dry habitat, it possesses 

 no more beauty than a half-dead apple tree in a neglected orchard. The 

 trunks resemble mesquite in Texas; but the Texas tree is redeemed by 

 the beauty of its foliage in summer, while the foliage of the singleleaf 

 pine is so pale and thin that it attracts no attention. 



CAROLINA HEMLOCK (Tsuga caroliniana) is of far less importance 

 than its northern neighbor which goes south along the Appalachian 

 mountains to meet it. The two species mingle on the mountain tops 

 from southwestern Virginia to northern Georgia. The Carolina hemlock 

 is usually confined to altitudes 2,500 or 3,000 feet above sea level, and 

 prefers rocky banks of streams. It does not usually occur in dense 

 stands of even moderate size, as the northern hemlock does. A few trees 

 in clumps or scattered solitary sepresent its habit of growth. Typical 

 development of the species occurs on the headwaters of the Savannah 

 river in South Carolina. For a long time this hemlock and its northern 

 relative were supposed to be the same. Botanists did not formerly 

 separate them, and the mountaineers do not generally do so now. There 

 are several differences, however, which may be observed upon close 

 examination, and by comparing the two species. The Carolina hem- 

 lock's leaves have more rows of stomata and therefore are a little whiter 

 on the under side. The leaves are also longer, and the cones are larger. 

 The tree does not attain the dimensions of the northern species, its 

 average size being forty or fifty feet in height, and two or less in diameter. 

 It is not abundant, and has never been and never can be much used for 

 commercial purposes. It is an attractive park tree and has been widely 

 planted. 



LIMBER PINE (Pinus flexilis) owes its name to its long, drooping 

 branches. It is often called white pine, Rocky Mountain white pine, 

 western white pine, and limber twig pine. It is not the tree usually 

 called western white pine (Pinus monticola), but is a high mountain 

 species, ranging from the Rocky Mountains of Montana to western 

 Texas; it grows also on the mountains of Arizona, Utah, Nevada, and 

 California. The upper limit of its range in the Sierra Nevadas is 12,000 

 feet. It descends to an altitude of only 4,000 feet in the Rocky Moun- 

 tains, and forms open, scattered stands of round-topped trees of little 

 commercial value, and is usually associated with western yellow pine or 

 Rocky Mountain cedar. At altitudes of 8,500 or 10,000 feet it is more 

 stunted, and associates with Lyall larch and other high mountain 



