92 SILVA OF NORTH AMERICA. conifers. 



Pinus contort a, var. Murray ana, is common on the Alaska hills, where it sometimes attains a 

 height of one hundred feet and a trunk diameter of eighteen inches, 1 and finds its most northerly home 

 in the valley of the Yukon River. It is the prevailing and characteristic tree on the interior plateau of 

 northern British Columbia, crossing the Rocky Mountains to the hills between the Athabasca River 

 and Lesser Slave Lake, and spreading southward along their eastern foothills at elevations of about 

 four thousand feet above the level of the sea to the Cypress Hills in southern Assiniboia ; it is common 

 in the interior of southern British Columbia on sandy benches and river flats and on mountain slopes 

 above a level of three thousand five hundred feet, often covering with dense forests great areas of 

 sandy soil in the basin of the upper Columbia. 2 In the United States the Lodge Pole Pine forms 

 forests on both slopes of the Rocky Mountains of Montana ; it is the prevailing tree on the Yellowstone 

 plateau in northwestern Wyoming, which at elevations from seven thousand to seven thousand five 

 hundred feet it covers with a dense nearly continuous forest; 3 it is also common on the Big Horn 

 and other mountain ranges of Wyoming, extending southward to those of southern Colorado, where 

 it abounds at elevations from ten to eleven thousand feet above the sea, 4 and to eastern Utah ; from 

 the western slope of the Rocky Mountains of Montana it spreads over the Bitter Root Mountains 

 of Idaho and over the ranges of eastern Washington and Oregon, where, usually at elevations 

 from four thousand five hundred to five thousand feet, it forms on high ridges great continuous 

 forests ; it is common on the mountains of northern California and ranges southward along the Sierra 

 Nevada, where it attains its greatest size and beauty and is the principal inhabitant of the alpine 

 forest, growing above the Firs on moraines extending for miles along the sides of rocky valleys at 

 elevations between eight thousand and nine thousand five hundred feet above the sea-level, and on 

 the rich alluvium of sheltered lake bottoms, where, four or five inches in diameter and forty or fifty 

 feet in height, 5 its stems are crowded like blades of grass ; on Gray Back of the San Bernardino Range 

 in southern California it forms the timber line, at heights of about ten thousand feet, with a nearly 

 continuous belt, descending three thousand feet lower with individuals scattered through the forest of 

 Yellow Pine, and in Bear Valley among the San Jacinto Mountains it finds its most southerly home 

 with small scattered groves at elevations of six thousand feet. 6 



The wood of Pinus contorta is light, hard, strong, although brittle and coarse-grained ; it is light 

 brown tinged with red, with thick nearly white sapwood, and contains broad very conspicuous bands of 

 small resinous summer cells, numerous small resin passages, and many obscure medullary rays. The 

 specific gravity of the absolutely dry wood is 0.5815, a cubic foot weighing 36.24 pounds. On the 

 coast of California it is used for fuel. The wood of the variety Murrayana is light, soft, not strong, 

 close, straight-grained, and easily worked but not durable ; it is light yellow or nearly white, with thin 

 lighter colored sapwood, and contains narrow inconspicuous bands of small summer cells, few small 



able to reproduce themselves under unnatural conditions ; and re- ing abundantly on the Stikive immediately east of the coast moun- 



gions formerly clothed with Spruces, Firs, and other Pines appear tains and thence inland ; and on the Dease and upper Liard and 



destined to receive a forest-covering of Pinus contorta, which, al- from the mouth of the Dease down the Liard to Devil's Portage, 



though comparatively worthless as a timber-tree, is of inestimable some miles east of the range which apparently represents the 



value in preserving the integrity of mountain slopes and protecting northern continuation of the Rocky Mountains. Farther east Pinus 



the flow of mountain streams. divaricata is the Pine of the great valley of the Mackenzie, although 



1 M. W. Gorman, Pittonia, iii. 69. it does not extend west of the Rocky Mountains to the head-waters 



2 G. M. Dawson, Can. Nat. ser. 2, ix. 327. — Macoun, Cat. Can. of the Liard. Pinus contorta, var. Murrayana, does not occur on 

 PI. 466. the upper Pelly, in ascending which it was first met with by Dr. 



" On the authority of Mr. W. H. Dall the northern limit of this Dawson in longitude 133° 30'. From this point down the Pelly 



tree has been given at the confluence of the Pelly and Lewis Rivers and up the whole length of the Lewes it is moderately abundant 



(lat. 62° 49' north) ; but as it there shows no sign of having reached (G. M. Dawson, I. c). 



its extreme point, it may probably be found some distance farther 3 Tweedy, Garden and Forest, i. 129 (Forests of the Yellowstone 



northward in the Yukon valley, although not so far as the mouth National Park). 

 of the Porcupine in latitude 63° 33'." (G. M. Dawson, Garden and 4 Brandegee, Bot. Gazette, iii. 32. 



Forest, i. 59.) 5 Muir, The Mountains of California, 200. 



Pinus contorta, var. Murrayana, was found by Mr. Dawson grow- 6 S. B. Parish, Zoe, iv. 351. 



