186 PAUL C. STAND LEY 



TRANSITION ZONE 



Extensive lumbering operations have been carried on about 

 Tierra Amarilla and well up toward the Brazos Canyon, where- 

 ever surface conditions are favorable. It is chiefly the timber 

 of the Transition Zone that has been cut, for that of the Canadian 

 Zone is usually on slopes or in canyons which are difficultly 

 accessible. On the lower hills and in the valleys about Chama 

 the general aspect of the vegetation has been much changed by 

 man, and most of the large trees have been cut off. Apparently 

 lumbering has been carried on in a rational fashion, and there 

 are none of the burns or of the tracts covered with dead branches 

 that spell desolation where the country has been "skinned," 

 as it has in so many places in both the west and the east. The 

 yellow pine is being gradually reestablished by nature and 

 young trees are seen everywhere, while the white fir reproduces 

 rapidly where conditions are at all favorable. 



The vegetation of the Transition Zone in this region may be 

 divided into two areas, typical Transition and Transition in 

 which there is a large Upper Sonoran element. The first in- 

 cludes the mountain sides and the banks of the streams at their 

 bases : and the second embraces the valley proper of the Chama 

 River and the slopes of the low hills. The line between the two 

 is rather sharply marked; for while both are, or have been, 

 covered with yellow pine, the herbaceous vegetation is com- 

 posed largely of different species, although many herbs and 

 shrubs are common to both, just as many are common to the 

 Transition and Upper Sonoran zones. 



In the life zone map of New Mexico published recently 2 there 

 is shown a broad belt of the Upper Sonoran extending along 

 the Chama River from Tierra Amarilla to Chama. This is 

 certainly incorrect, if one is to judge of the zones by the limits 

 laid down by the author of the text which accompanies the map. 

 The Transition, in northern New Mexico, is the zone of yellow 

 pine, and all of the area under discussion is or was once covered 

 by that tree, except along the banks of the streams. There is 



2 Bailey, Vernon, Life zones and crop zones of New Mexico. N. Amer. Fauna 

 No. 35. 1913. 



