PLANT SUCCESSIOIsr AND RANGE MANAGEMENT. 7 



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- 

 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.^ 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 

 range, it is essential to know the ecological peculiarities and economic 

 value of each. 



^ 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. 



