OCT., 1899.] 



WHITE-BARK PINE BELT. 



41 



and a half across (horizontally), nuist contain thonsands of acres of the 

 dwarf, flattened pines. Along its lower edge, singnlarly enough, trees 

 of the same species suddenly stand upright and grow to large size, 

 forming a rather solid forest, i^erhaps 30 feet in lieight, with an abrupt 

 front facing the dwarf pines above. The suddenness of the transition 

 is unusual and difficult to explain. 



The forest just mentioned is probably the largest continuous area of 

 Pinm albicauUs on Shasta. Situated a little below timberline, it 

 stretches, apparently witbout interruption, from ^orth Gate Buttes 

 to Diller Canyon, a distance of fully 5 miles, thus encircling the north- 

 west quadrant of the mountain, including Shastina. 



Perhaps the most attractive grove of white-bark pines on Shasta is 

 one that fills an open gulch or glade on the east side of Xorth (late 

 Buttes. Here, in the lower part of their belt, the trees are large and 

 uncommonly symmetrical, and the gray pumice soil is covered with 

 silvery lupines. In ascending the gulch the pines gradually decrease 

 in size until at 'The Gate' (alt. 8,500 feet) they are dwarfed and their 

 tops are broadly flattened. 



The normal altitudinal limits of the white-bark i)ines on Shasta are 

 hard to fix. On the south and southwest sides the trees descend in 

 places to 7,500 feet and range thence upward on the hottest ridges to 

 an extreme limit of 9,800 feet. But this extreme altitude is attained at 

 two points only — on the long ridge above 'The [South] Gate' (near lied 

 Butte) and on a ridge about a quarter of a mile west of Mud Creek 

 Canyon. 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 9,500 

 would be a fair average for their upi)er limit on the warmer southerly 

 slopes. 



On the cold northeast slope, just south of Brewer Creek, they descend 

 21753— No. 16 6 



