10 BULLETIN 680, U. S. DEPARTMENT OF AGRICULTUEE. 



The foliage of alpine larch is a liglit_, bluish green, turning bright 

 lemon-yellow in autumn, after the first sharp frost. The tree is then 

 readily detected by this color on distant high, inaccessible peaks and 

 crests. The juvenile or primary form of leaf grows singly on new 

 shoots. The adult leaves occur in clusters of from 30 to 40 or more. 

 They are somewhat indistinctly 4-angled, and from about 1 inch to 

 1 f inches in length (PI. Ill, a) . A cross section of the leaf shows two 

 resin ducts, one in each of the two smaller angles. 



The cones mature in one season, ripening early in August, and 

 opening soon afterwards to shed their seed. By late autimm most 

 of the cones have fallen from the trees, a few sometimes remaining 

 until early winter. They are from about 1^ to 2 inches long (PL III). 

 The bristle-pointed bracts (PL III, c) that project from among the 

 cone scales are a deep purple, while the cone scales are a deep purple- 

 red. Their margins have a fringe of tangled, very fine white wool, 

 which is also more or less spread over the outer surface of the scales. 

 Mature seeds (PL III, e) are pale reddish brown. The seed-leaves are 

 usually 5 in nmnber. 



The wood of alpine larch is of a clear red-brown or deep orange- 

 brown color, with a thin layer of whitish sapwood. It is narrow- 

 ringed, hard, and tough. It ranks second in weight among our native 

 larch woods, a cubic foot of dry wood weighing about 44 pounds. 

 While the wood is suitable for rough lumber, railway ties, and mine 

 timbers, it is not used for these purposes, probably because of the 

 generally small size of the tree and the fact that it grows only in 

 rough, comparatively inaccessible places. 



OCCURRENCE AND HABITS. 



Larix lyallii inhabits high mountain slopes and plateaus at and 

 near timber line at elevations between about 4,500 and 7,600 feet 

 (Map No. 3). The tree shows a preference for northern aspects and 

 often for "passes," sheltered sides of crests, and high divides. Its 

 environment is one of heavy snowfall, which comes early and remains 

 well into the summer, or, in some parts of its range, throughout the 

 year. It is very moderate in soil requirements, growing in the rockiest 

 soil and even in crevices of rough granite slopes, provided there is 

 abundant moisture. For the most part, alpine larch occurs in small, 

 pure groves, or sometimes in open stands with white-bark pine, 

 mountain hemlock, alpine fir, and Engelmann spruce. It appears to 

 be hardier than these alpine associates, ascending higher than they 

 do in moist basins and showing greater vigor; while its thin fohage, 

 compact, strong trunk, tough branches, and firmly anchored roots 

 enable it to withstand without serious damage the rigors even of high 

 bleak summits. 



