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NATURALIST'S GUIDE TO THE AMERICAS 



is about 80 and the average winter 

 temperature is around 30. 



Cutting is not extensive because of 

 the rather poor quality of the timber. 

 Grazing is not an important factor. 

 Fire is the only seriously damaging 

 agent. 



FAUNA OF THE YELLOW PINE AND 



DOUGLAS FIR FORESTS 

 (TRANSITION ZONE) 



In the yellow pine and Douglas fir 

 forests the fauna is so intermingled that 

 it is impossible to separate out those 

 species characteristic of one locality. 

 This region is the home of the black and 

 grizzly bears, mountain coyote (Cams 

 lestes), mountain weasel (Mustela arizo- 

 nensis), pine marten (Martes caurina), 

 Pacific raccoon (Pyocyon psora}, Cali- 

 fornia gray fox (Urocyon cinereoargen- 

 teus group), bushy-tailed wood rat 

 (Neotoma cinerea subspp.). Douglas 

 ground squirrel (Citellus beecheyi group), 

 many chipmunks (Eutamias) , Sierra 

 flying squirrel (Glaucomys sabrinus 

 group), mule deer (Odocoileus hemionus), 

 black-tailed deer (0. columbianus 

 subspp.). Bird life in this region in- 

 cludes the western red-tailed hawk, 

 golden eagle, Pacific horned owl, spotted 

 owl, California woodpecker, nighthawk, 

 Sierra woodpecker, Lewis woodpecker, 

 flicker, blue-fronted jay, western and 

 mountain bluebird, Sierra cross-bill, 

 sierra junco, tree swallow, dipper, 

 mountain chickadee, mountain quail 

 and Sabine ruffed grouse. 



FIR TYPE (CANADIAN) 



Altitudinally, the true fir type is just 

 above the mixed coniferous. It includes 

 the forests of white fir (Abies concolor) 

 and red fir (Abies magnified] , both pure 

 and in mixture. The altitudinal limits 

 vary widely with the latitude, but 

 average from 6000 to 8000 ft. The stands 

 are often dense and few annuals or 

 grasses prevail except in meadows 

 where heavy grazing by sheep and cattle 

 is permitted. The stands, because of 

 their relative inaccessibility, and low 

 value for commercial lumber, are not 



being exploited to any extent and proba- 

 bly will not be for some time to come. 



The precipitation is chiefly in the 

 form of snow, and varies between 30 

 and 50 in. annually. Average minimum 

 temperatures during the winter do not 

 exceed 25, and the mean summer tem- 

 perature is not over 65, the average 

 annual temperature is not above 40. 

 Because of low temperature and depth 

 of snowfall, the snow lasts till late in 

 the summer season. The growing season 

 is from June to October. 



In the fir type are found the mountain 

 weasel, Cascade red fox and high Sierra 

 red fox (Vulpes cascadensis and V. 

 necator), Pacific fisher, bob-cat (Lynx 

 rufus calif or nicus), bushy-tailed wood- 

 rat (Neotoma cinerea subspp.), alpine 

 chipmunk (Eutamias alpinus), golden- 

 mantled ground squirrel (Callospermo- 

 philus chrysodeirus) , yellow-haired por- 

 cupine, chickadee. In this region is 

 also the Sierra sooty grouse, the gos- 

 hawk, Sierra nighthawk, Hammond 

 flycatcher, Lincoln sparrow, and varied 

 thrush. 



SUBALPINE (HUDSONIAN) 



The sub-alpine forests include a 

 variety of species at elevations where 

 the growing season is short and tem- 

 peratures are not excessive even in 

 summer. Included in this forest are 

 the mountain hemlock (Tsuga merten- 

 siana*), white bark pine (Pinus albicau- 

 lis), foxtail pine (Pinus balfouriana) , 

 western white pine (Pinus monticola} 

 and lodgepole pine (Pinus contorta). 

 The forests are not extensive, and are 

 utilized to some extent by grazing. No 

 lumbering of consequence will be carried 

 on in this region because of the relatively 

 poor quality and inaccessibility of the 

 stands. The trees of this zone exist 

 chiefly only on the higher mountain- 

 peaks and ridges. 



Climatic conditions are usually severe; 

 the minimum temperature during the 

 winter is not known, but probably is 

 not below that of the fir type, while the 

 precipitation is probably not over 30 

 or 40 in. annually, practically all coming 



