194 CLIMAX FORMATIONS OF WESTERN NORTH AMERICA. 



appearance of being integral parts of the forest communities in which they 

 occur, while in the form of shrubs and bushes they are equally at home in 

 chaparral. The consequence is that the same species may appear as an impor- 

 tant if not dominant constituent of chaparral, woodland, and forest, and its 

 proper r61e becomes very difficult of determination. As a community, the 

 woodland occupies fairly narrow limits of altitude, and hence becomes massive 

 only on great upland plateaus, such as the Mesa Verde. In general, it occurs 

 on hillsides and mountain slopes in regions of rough topography. As a con- 

 sequence, it not only lacks mass and often continuity as well, but it is also 

 more or less obscured by admixture with dominants from the zones above and 

 below. This is emphasized by the character of the dominants. Where the 

 oaks are abundant, they give the woodland the appearance of belonging to 

 the chaparral, or of constituting an oak savannah, while the pifion and cedar 

 aline it rather with the forests of yellow pine and fir. However, the chief 

 source of confusion lies in the ability of all the dominants, but of the cedar 1 

 especially, to invade rocky areas, largely as a result of the readiness with 

 which their fruits are distributed by rodents and birds. As a consequence, 

 an open chaparral-like type occurs throughout the West from Texas to Cali- 

 fornia and from Mexico to Montana. It agrees with the climax woodland 

 only in the presence of one or two of the dominants, but differs from it in 

 habitat, structure, and development. In some regions, it will pass into the 

 climax, but as a rule it is an anomolous subclimax stage which yields to chap- 

 arral, sagebrush, or forest. 



Typically, the woodland consists of small trees 20 to 40 feet high, belonging 

 to the three genera, Juniperus, Pinus, and Quercus. While these vary widely 

 in leaf character, they agree in being evergreen and xerophytic. They form 

 fairly dense crowns and in favorable situations make a continuous canopy 

 and a fairly uniform shade. The term woodland was apparently first applied 

 by the Forest Service, and is used to include all areas in which pifion and cedar 

 are characteristic. In the present case, woodland is used only for the climax 

 proper, consisting of cedar, pines, or oaks variously mixed in forests of low 

 stature. About such climax areas are often much wider ones in which one of 

 the dominants constitutes a grassland or scrub savannah. 



Range and extent. — The woodland formation is essentially southwestern 

 in extent. It finds its best expression as a climax on the high plateaus of the 

 Colorado Basin, but it occurs from the Davis and Guadalupe Mountains of 

 western Texas through northern Mexico to Lower California. It extends 

 northward along the foothills in New Mexico and Colorado to southwestern 

 Wyoming, and then westward through Utah and Nevada to northern Cali- 

 fornia. Over by far the greater part of this vast area it forms a more or less 

 continuous belt along the mountain ranges, broadening out into extensive 

 forests only where tablelands of median altitude permit. The pifion-cedar 

 association is much the most extensive as well as the most typical, while the 

 oak-cedar community is restricted to southwestern Texas, southern New 

 Mexico and Arizona, and northern Mexico, and the pine-oak to California. 

 The cedar ranges far beyond the climax region, forming characteristic com- 

 munities on rocky slopes and escarpments from Scot t's Bluff and Pine Ridge 



U~n view of the divergence in the botanical use of cedar and juniper for various species of 

 Juniperus, cedar has been preferred as representing the common usage in the West. 



