PLAOT SUCCESSION AND RANGE MANAGEMENT. T 
the life history of the different species, and notably upon the time of 
seed maturity. 
THE PLANT TYPES. 
Following the general classification of the successive plant stages, 
both in the building up and in the deterioration of the range, an 
intensive study of the succession of the vegetation was carried out on 
overgrazed protected areas, on overgrazed unprotected areas, and on 
undergrazed depleted lands, the quadrat method being used. 
The investigations were conducted in the vicinity of the Great 
Basin Experiment Station, located in that part of the Wasatch 
Mountains embraced by the Manti National Forest in central Utah. 
The area studied lies between about 9,000 and 11,000 feet in eleva- 
tion in the spruce-fir type — in the subalpine (Hudsonian) zone — 
which includes the typical summer range. In flora and climate this re- 
n gion is somewhat intermediate between the extremes of the North- 
west and the Southwest. Broadly considered, the species making up 
the predominating vegetation are similar to those conspicuous on the 
summer ranges included within the National Forests in northern 
New Mexico, Utah, western Colorado, and parts of Idaho and Ne- 
vada ; and the conditions in the high mountain ranges generally are 
such that the principles involved will apply elsewhere. 
Careful grouping of the vegetation up and down the scale of de- 
velopment into divisions which can be readily recognized and used in 
applying the principles here set forth reveals four major stages of 
vegetation. These stages embrace all the lands which receive their 
moisture directly from precipitation, but do not include the rela- 
tively small acreage of marsh lands and other similar areas. 1 The 
*•< plant stages from the subclimax down to the most transitory cover 
are as follows : 
The wheat-grass consociation (subclimax stage). 
The porcupine-grass-yellow-brush consociation (mixed grass-and-weed 
stage). 
The foxglove-sweet-sage-yarrow consociation (second or late weed stage). 
The ruderal-early-weed consociation (first or early weed stage). 
In order fully to appreciate the significance of the changes that 
take place in the development of the vegetation either toward or 
away from the subclimax type, as well as the significance of the com- 
ponent consociations in their relation to the management of the 
i range, it is essential to know the ecological peculiarities and economic 
value of each. 
1 Justification for the elimination of wet meadows and similar areas is found in the 
facts that such lands are limited in extent, and the forage which they produce is rather 
inferior, and is seldom grazed destructively. 
