WHITE FIR IN THE KLAMATH BASIN 



A S11.VICULTURA1, Study 



By a. F. Kerr 



The region included in this study lies on the east slope of the 

 Cascade Alountains in Southern Oregon. In elevation it ranges 

 from 4,140 — the level of Upper Klamath Lake — to about 7,000 

 feet. The general slope is toward the east, but, locally, every 

 aspect is encountered. A series of high volcanic cones with 

 heavy lateral spurs, and deep narrow canyons furnishes the main 

 topographic features of this region and presents a striking con- 

 trast to the broad, flat basin of Four Mile Creek, which, with its 

 tributaries, separates the region from the main crest of the Cas- 

 cades. 



The precipitation here averages about 20 inches annually, 

 largely in the form of snow. The growing season is short, be- 

 ginning about May ist, or later. Killing frosts occur as late 

 as July and as early as September, even on the better protected 

 sites. The summers are hot and dry so that fire danger is in- 

 creased to a maximum. Thunder storms are more or less fre- 

 quent and the damage by lightning either directly, or through re- 

 sulting fires, is very great. 



The soil is of volcanic origin, and of a medium quality. It 

 varies from fairly deep and loose at the bottom of slopes and 

 in gulches, where it is mixed with decaying vegetable matter, to 

 thin and rocky on upper slopes and exposed points. At higher 

 elevations there are large areas of lava rock, either very thinly 

 covered or entirely bare. The soil is easily pulverized and washes 

 badly where exposed to heavy rains, and, on account of its friable 

 texture, it is especially subject to heaving by frost. 



A ties Concolor. 



Yellow pine, Douglas fir, White fir and Shasta fir are the 

 species of commercial importance in this region, although Lodge- 

 pole pine occurs quite abundantly on limited areas. The under- 



