Brazing Investigations <>\\ Our \ational Forests 19 



in jr. On the gra/ed areas, then, not only a better seedling 

 stand is secured but the forage crop is utilized. 



In certain habitats on the experimental allotments the 

 for.tge seedlings occurred so densely in the beginning of the 

 season th.il individual competition was sure to enter in and 

 eliminate the weaker ones. Prom a large number of counts 

 in tin- varied localities it was found that virtually one-half 

 of the original stand was killed by adverse physical conditions 

 and the greatest injury occurred during the fore part of the 

 season. While the upland ranges enjoy more precipitation 

 than those of lower elevation, the friable surface soil, to a 

 depth of 2 or 3 inches, dries out readily, and the lack of water 

 is the primary cause of the loss of seedlings. A few inches 

 beneath the surface layer an abundance of moisture is nearly 

 always present at any time during the season. It is found 

 tint forage seedlings of average moisture requirements suc- 

 cumb when the soil in the vicinity of their roots varies from 

 five to nine per cent. The curves in Plate I show the rela- 

 tion of soil moisture during the growing season in the soil 

 <tratuni in which the forage seedlings grow and in the soil 

 in which the established plants have their roots. 



It will be observed that there is a correlated behavior in 

 the water content in the two soil strata, yet the per cent of 

 water decreases perceptibly more rapidly in the upper layer. 

 The figure also shows that the driest period of both depths of 

 soil in 1909 occurred between July 15 and 25. At this time 

 the seedlings had a meager root system and fully four-fifths 

 of the loss occurred between those dates. By the end of the 

 second season the seedlings are so deeply rooted that drought 

 is not liable to injure them. (See Plate I.) 



In order to secure reproduction from the valuable native 

 range plants to such an extent as to materially increase the 

 forage supply within a reasonable length of time, it is evident 

 that the range must support at least a sparse stand of the 

 species valuable for grazing. The time required for a thorough 

 re-establishment of the forage crop will largely depend upon 

 the density of the forage stand, vigor of the vegetation, the 

 seed habits and vitality of the seed crop, the climatic conditions 

 and the care with which the lands are grazed during the time 

 required for the new growth to become established. On lands 



