Changes in Ponderosa Pine Bunchgrass Ranges in Northern Arizona Resulting from Pine Regeneration and Grazing

Abstract

open than they are today. Present forest conditions contrast strikingly with early photographic records and descriptions (4). A deficient undergrowth of seedling and sapling pines was reported in the forest surveys of 1901-1902 and as a consequence the forest floor was more fully occupied by herbaceous species. This may explain in part why early estimates of livestock greatly exceeded present numbers. At the turn of the century, the inadequate regeneration of ponderosa pine caused grave concern among southwestern foresters (7, 8). The acute problem of natural reforestation was greatly relieved when, in 1919, an unusual distribution'.of moisture favored the suc-