The mountain brush type in Utah was studied in 1932, 1942, and 1969 to determine the vegetation changes and trends after grazing and protection from grazing for 37 years. Analyses for cover, frequency and composition percentages, production and plant counts were made on fifty 100 square-foot plots in a ten-acre exclosure and on a five-acre grazed area adjacent to the exclosure. Production, cover and composition percentages for good and fair forage species of grasses and browse have decreasesed on the grazed plots whereas they generally increased in the ungrazed plots. Forbs of intermediate forage value have increased in production, cover and composition percentages in both the grazed and ungrazed plots. The effect of intensive livestock grazing on the mountainbrush type in Utah has been to reduce the proportion of herbaceous vegetation and the better forage shrubs and the increase the propotion of poorer forage species.