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NATURALIST'S GUIDE TO THE AMERICAS 



northwest corner about three townships 

 lie in a State Game Preserve. Graz- 

 ing is general. Timber cutting is very- 

 localized and the greater part of the 

 Forest is virgin. The major types are: 

 western yellow pine 30%, grass 24%, 

 Douglas fir 17%, larch-fir 12%, sub- 

 alpine 10%. 



Weisert. O. S. L. R. R. Supervisor's 

 headquarters. 



Wyoming National Forest (Wyoming) 



The Wyoming Forest (966,954 acres) 

 lies upon a mountain range of a plateau- 

 like character, becoming more rugged 

 northward. This Forest contains large 

 areas of lodgepole pine which are being 

 widely cut over at the present time. 

 The Swift Creek watershed near Afton 

 is closed to sheep, however, as a protec- 

 tion to the Afton water supply. At the 

 north end of the Forest in high moun- 

 tainous country is a game refuge. Graz- 

 ing is general and timber cutting is not 

 restricted on any areas. The major 

 types in order of abundance are: brush 

 25%, lodgepole pine 21%, Douglas fir 

 15%, aspen 9%, sage 8%, grass 6%. 



Kemmerer, Wyomingf. O. S. L. R. 

 R. Supervisor's headquarters. 



9. NATIONAL FORESTS OF THE 

 SOUTHWESTERN DISTRICT (3) 



By G. a. Pearson 



The National Forests of Arizona and 

 New Mexico cover about 22 million 

 acres and comprise approximately 65% 

 of the forest area in the two States. 

 They are situated in high mountain 

 regions ranging from 2000 to 13,000 ft. 

 in altitude. Although the forest boun- 

 daries occasionally take in desert and 

 brush lands down to 2000 ft. in elevation, 

 the true forests, as distinguished from 

 brush and woodland, rarely occur below 

 7000 ft. The upper altitudinal limit 

 of tree growth is around 11,500 ft. Four 

 distinct forest associations or forest 

 types are recognized. They are, in 

 order of altitudinal occurrence, begin- 

 ning with the lowest, the woodlands, 



the yellow pine type, the Douglas fir 

 type and the Engelmann spruce type. 

 The altitudinal limits vary with soil, 

 climate, aspect and other local condi- 

 tions. Other factors being equal, any 

 given forest type occurs roughly 1000 

 ft. higher on southerly than on north- 

 erly aspects. Since the same forest 

 type varies but little on different Na- 

 tional Forests in the Southwest, the 

 following descriptions will apply in a 

 general way over the entire region. 



WOODLANDS (UPPER SONORAN ZONE) 



Woodland areas are not, strictly 

 speaking, classed as forests because the 

 trees do not attain saw timber size. 

 The woodlands occur mostly between 

 the altitudinal limits of 5000 and 7000 

 ft., though in some localities they extend 

 above or below these extremes. The 

 average annual precipitation seldom 

 exceeds 17 in. and falls as low as 12 in. 

 Mean annual temperatures range from 

 50° to 55°. 



Two distinct types of woodland occur. 

 In the one most commonly encountered, 

 the dominant trees are the junipers 

 (Jtmiperus rnonosperma, J. utahensis, 

 J. pachyphloea and /. scopulorum) , 

 and the piiion, {Pinus edulis). In 

 southern Arizona, notably the Coronado 

 National Forest, is a woodland composed 

 mainly of oaks, (Quercus emoryi and Q. 

 arizonica) . 



Woodland stands are usually open 

 and the space between the trees is 

 generally occupied by short grasses. 

 Cutting for fuel and posts removes 

 most of the mature and overmature 

 trees, but provision is always made for 

 seed trees to restock cut-over areas. 

 Because of the accessibility of the wood- 

 lands to settled communities and the 

 demand for their wood and grazing 

 resources, it is probable that they will 

 be exploited to the limit of their capac- 

 ity. The piiion jay, scaled partridge, 

 Woodhouse's jay, wild turkey, white- 

 tailed deer (Odocoileus), mule deer 

 (Odocoileus hemiomis group), coyote 

 {Canis sp.), rock squirrel (Otospermo- 

 philus), prairie dog (Cynomys), cotton- 



