Throughout the late 1800s and into the first part of the 20th century, central Arizona experienced a period of heavy grazing from cattle and sheep ranching. The Sierra Ancha Experimental Forest first began as a series of range exclusion plots established in the early 1920s to study the threat of erosion into the newly established Roosevelt Lake. Early pioneers in southwestern rangeland ecology including M.W. Talbot and C.K. Cooperrider took painstaking efforts to establish and record plant community characteristics within dozens of meter square survey plots scattered throughout the experimental forest. What began as an erosion study quickly morphed into a plant demography study that was continuously monitored from 1920 – 1960.