Nov. i6, I9M Revegetation of Range Lands 127 



SEEDWNG RBPRODUCTION SECURED 



It will be seen that as a result of the deferred system of grazing the 

 density of forage seedlings was from 2 to 10 times as great in 1909 as in 

 1908. Quite as important as the density was the identity of the seedling 

 species. It will be recalled that where yearlong grazing was carried on, 

 seedlings, aside from the annual weeds, consisted of two early-maturing 

 annual plants, sickle sedge and slender hair-grass, together with a more 

 valuable species, western porcupine grass. On the yearlong protected 

 plots practically the only species were the few with small, heavy seeds, 

 and the two porcupine grasses (Stipa minor and S. occidentalis) which 

 are self-planting. Table VII shows that where deferred grazing was car- 

 ried out the ground became stocked with seedling plants of all species 

 which produce seed. The most valuable species, mountain bunch-grass, 

 which failed completely under yearlong grazing and yearlong protection, 

 responded exceptionally well. Its seedlings were found in all situations 

 where there were parent plants to produce the necessary seed crop. 



In the Canadian zone several of the valuable species which failed to 

 reproduce under either of the other systems regenerated more or less 

 abundantly under deferred grazing. 



Although, under deferred grazing, forage seedlings were found wherever 

 there were enough parent plants to produce the necessary seed, the propor- 

 tion of the seedling stand which ultimately became established depended 

 mainly upon the habitat and climatic conditions, as well as upon sufficient 

 protection from grazing during the period of establishment. 



LOSS OF SEEDLING REPRODUCTION BY GRAZING 



To determine the extent to which moderate deferred grazing reduces 

 the stand of valuable forage seedlings and whether the subsequent seed- 

 ling stand resulting from the additional seed crop when thoroughly 

 planted by trampling will offset the number of seedlings lost through 

 grazing, observations were made on selected plots at medium and high 

 elevations. The first observations recorded the character of the vegeta- 

 tion in and around each quadrat for a radius of 10 feet; the density of the 

 herbaceous vegetation within and without the quadrat; the character of 

 the soil and the slope and exposure; and the total number and identity 

 of the seedlings within the quadrat, and their health vigor at the time 

 of observation. With such data it was possible to account for any unusual 

 loss resulting from subsequent grazing. It was recognized, for example, 

 that a seedling, even when deeply rooted, is much more likely to be 

 destroyed by trampling if it is situated on an abrupt hillside, especially 

 in a denuded gravelly soil, than if situated in a level glade between tufts 

 of grass with intertwining roots. Again, a seedling growing under ad- 

 verse moisture conditions does not develop as elaborate and deep a root 

 system as one which has received enough moisture to furnish the neces- 



