Bui. 1105, U. S. DeDt. of Agriculture 



Plate 



77 



F 43860A 



Fig. I .—Clay Flat in a Virgin Stand of Western Yellow Pine. The 

 Soil is a Stiff Clay, Compacted by the Tramping of Cattle and 

 Sheep. 



Overgrazing has destroyed the original vegetation, which has given way to "six-weeks grass" 

 and noxious weeds. Seedlings are about six times as numerous in the weed clumps as in 

 the open spaces. 



F 49I76A 



Fig. 2. 



-Near View of a Clump of Senecio spartioides, Showing Litter 

 at Base, and Two Pine Seedlings. 



These weeds not only favor germination, but because of their unsavory character protect young 

 seedlings against damage by grazing animals. 



