. Results of a biological survey of mount Shasta, California. ly 5 miles, thus encircling the north-west quadrant of the mountain, including Shastina. Perhaps the most attractive grove of white-bark pines on Shasta isone that fills an open gulch or glade on the east side of Xorth (lateButtes. Here, in the lower part of their belt, the trees are large anduncommonly symmetrical, and the gray pumice soil is covered withsilvery lupines. In ascending the gulch the pines gradually decreasein size until at The Gate (alt. 8,500 feet) they are dwarfed and theirtops are broadly flattened. The normal alt
. Results of a biological survey of mount Shasta, California. ly 5 miles, thus encircling the north-west quadrant of the mountain, including Shastina. Perhaps the most attractive grove of white-bark pines on Shasta isone that fills an open gulch or glade on the east side of Xorth (lateButtes. Here, in the lower part of their belt, the trees are large anduncommonly symmetrical, and the gray pumice soil is covered withsilvery lupines. In ascending the gulch the pines gradually decreasein size until at The Gate (alt. 8,500 feet) they are dwarfed and theirtops are broadly flattened. The normal altitudinal limits of the white-bark i)ines on Shasta arehard to fix. On the south and southwest sides the trees descend inplaces to 7,500 feet and range thence upward on the hottest ridges toan extreme limit of 9,800 feet. But this extreme altitude is attained attwo points only—on the long ridge above The [South] Gate (near liedButte) and on a ridge about a quarter of a mile west of Mud CreekCanyon. On the west rim of the canyon the pines stop at 9,500 feet. Fig. 23.—A laini- prdstrate tree of whitrhark pine, a liltli- below timberline. and on the ridge on the east side at 8,600. Probably 9,300 to 9,500would be a fair average for their upi)er limit on the warmer southerlyslopes. On the cold northeast slope, just south of Brewer Creek, they descend21753—No. 16 6 42 NORTH AMERICAN FAUNA. [N-n. 16. on a biirrou ])umice slo])e to 7,000 lect, where, sparingly mixed withalpiue hemlocks, they meet tlie iii)]>er limit of Sliasta liis and silverpines. ]Jlack Alpine nE:\(K {rsinia mrrtensland^).—lUit the wliite-bark pine, although the dominant and most widely distributed tree ofthe up])er timber belt, is not the only tree, for in i)laees it is mixedwith or re])laced by the black alpine hemlock. Shasta is a Yevy drymountain, and yet the white-bark pine thrives on its driest slopes andgrows among the bare, naked blocks of lava where tree life seemsirai)ossible. The hemlock re(
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Keywords: ., binomial=pinusalbicaulis, common=whitebarkpin, taxonomy
