PLAlSTT SUCCESSIOISI' AND BANGE MAjSTAGEMENT. 



The rather strict line of demarcation in the habitat requirements 

 of the two forms may be explained in two waj's — (1) hj the differ- 

 ence in the distribution of the available moisture of the soil and (2) 

 by the depth to which the roots of the two grass forms extend. 



Fig. 2. — Relative height and character of root system of typical wheat grasses of the 

 bunched and of the turfed habit of growth. A, Blue bunch wheat grass {Agroppron 

 spicatum) : Ad, Small wheat grass (Agropyron dasystachyum) ; AT, Slender wheat 

 grass {Agropyron tenerum). 



By far the greater portion of the absorbing surface of small wheat 

 grass is confined to the upper 8 inches of soil, the average maximum 

 depth of individual roots not exceeding about 15 inches (fig. 2). 

 Because of the densely matted sod on areas where small wheat grass 



