22 CONCEPT AND HISTORY. 



Sampson, 1908, 1909, 1913, 1914. — The series of reports by Sampson on 

 revegetation in the Wallowa National Forest constitute a contribution of the 

 first importance to the science of grazing. They likewise furnish a large 

 amount of experimental data as to grazing indicators in the montane and 

 subalpine zones. The general results (1914:146) are applicable to a wide 

 range of grasslands and are summarized below. They not only take into 

 account the need of thoroughgoing and extensive studies of quadrats, factors, 

 and succession, but they also consider in detail the ecological requirements of 

 the various species. 



" (1) Normally the spring growth of forage plants begins in the Hudsonian 

 zone about June 25. For each 1,000 feet decrease in elevation this period 

 comes approximately 7 days earlier. 



"(2) In the Wallowa Mountains the flower stalks are produced approxi- 

 mately between July 15 and August 10, while the seed matures between 

 August 15 and September 1. 



" (3) Even under the most favorable conditions the viability of the seed on 

 summer ranges is relatively low. 



" (4) Removal of the herbage year after year during the early part of the grow- 

 ing season weakens the plants, delays the resumption of growth, advances the 

 time of maturity, and decreases the seed production and the fertility of the seed. 



"(5) Grazing after seed-maturity in no way interferes with flower-stalk 

 production. As much fertile seed is produced as where the vegetation is pro- 

 tected from grazing during the whole of the year. 



" (6) Germination of the seed and establishment of seedlings depend largely 

 upon the thoroughness with which the seed is planted. In the case of practi- 

 cally all perennial forage species, the soil must be stirred after the seed is 

 dropped if there is to be permanent reproduction. 



" (7) Even after a fertile seed crop has been planted there is a relatively 

 heavy loss of seedlings as a result of soil heaving. After the first season, how- 

 ever, the loss due to climatic conditions is negligible. 



" (8) When 3 years old, perennial plants usually produce flower-stalks and 

 mature fertile seed. 



" (9) Under the practice of year-long or season-long grazing, both the growth 

 of the plants and seed production are seriously interfered with. A range so 

 used, when stocked to its full capacity, finally becomes denuded. 



" (10) Year-long protection of the range favors plant growth and seed pro- 

 duction, but does not insure the planting of the seed. Moreover, it is imprac- 

 ticable because of the entire loss of the forage crop and the fire danger resulting 

 from the accumulation of inflammable material. 



"(11) Deferred grazing insures the planting of the seed crop and the per- 

 manent establishment of seedling plants without sacrificing the season's 

 forage or establishing a fire hazard. 



"(12) Deferred grazing can be applied wherever the vegetation remains 

 palatable after seed maturity and produces a seed crop, provided ample water 

 facilities for stock exist or may be developed. 



" (13) The proportion of the ranges which should be set aside for deferred 

 grazing is determined by the time of the year the seed matures. In the 

 Wallowa Mountains, one-fifth of the summer grazing season remains after the 

 seed has ripened, and hence one-fifth of each range allotment may be grazed 

 after that date. 



" (14) The distribution of water and the extent of overgrazing will chiefly 

 determine the area upon which grazing should first be deferred. 



