1936] MAMMALS AND LIFE ZONES OF OREGON 27 



In the Wallowa and Baker Ranges of the Blue Mountains, Cana- 

 dian Zone covers the high middle slopes from approximately 5,000 

 to 7,000 feet on the northeast slopes and 6,000 to 8,000 on the warmer 

 southwest slopes, but varying considerably in different parts of the 

 ranges (fig. 5). The highest peaks in the Baker Range reach to 

 8,920 and 9,097 feet, according to the United States Geological Survey 

 map, while in the Wallowa Range the Forest Service map shows the 

 higher peaks reaching from 9,000 to 9,800 feet. Considerable masses 



s.vy. ^^T>\ N-C. 



So no ra n 

 Sea level 



FIGURE 5. Life zones in the Wallowa Mountains from the northeast to the southwest 

 exposures, the zones considerably elevated by moderately high base level around two 

 sides of the mountains. 



of permanent snow and ice and one small glacier on these peaks 

 indicate their altitude. 



The Steens Mountains, with a 4,000- to 5,000-foot base level all 

 around, show the highest zone levels in the State. The Canadian 

 Zone extends from about 6,000 to 7,500 feet on cold slopes and 7,000 

 to 8,500 feet on warm slopes, but the mountains are so bare of timber 

 and vegetation in general that their zones are not clearly marked 



9,354 feet 



S.W. ^ ^_ .A N.E. 



Sea /eve/ 



FIGURE G. Life zones of the Steens Mountains, showing approximate levels of life 

 zones on northeast and southwest exposures and emphasizing the elevating effect of 

 high base level on the full set of zones. 



(fig. 6). The extreme aridity of the climate prevents any real forest 

 growth, while erosion and overgrazing have destroyed much of the 

 native flora and fauna. 



