FOREST CONDITIONS. 361 



and throughout the Interior Basin arid conditions 

 prevail, and hence wherever forest areas occur, 

 the trees stand open and are stunted, and gener- 

 ally of no commercial value. Yet the open pine 

 forest of the Blue Mountains, of the slopes and 

 plateau of eastern Oregon, made up of Bull Pine, 

 furnishes at least a welcome local timber supply ; 

 and the northern part of Washington, where 

 moisture conditions improve, shows the effect in 

 permitting an extension of the Rocky Mountain 

 forest type of northern Idaho, with Bull Pine and 

 Silver Pine of commercial value accompanying the 

 comparatively valueless Lodge-pole Pine. 



The Pacific coast forest presents four types. 

 The northern type, covering the west slope of the 

 Cascade and the Coast ranges through Washington 

 and Oregon, derives its value mainly from the 

 Douglas or Red Fir, and is characterized both by 

 density of stand and individual development and 

 by dense undergrowth in response to the great 

 humidity of the climate. Associated with the fir is 

 found a hemlock of not much inferior develop- 

 ment, but at present left unused, and the Giant 

 Cedar. In the higher elevations some excellent true 

 firs, Silver Pine, Engelman, and other spruces add 

 variety, and along the seashore the Sitka Spruce 

 and Port Orford Cedar of limited distribution, while 

 Yellow or Bull Pine occupies the sandy flats and 

 drier slopes. In its extension over the Coast Range 

 of California the type changes somewhat, although 



