Long-term Recovery of Wyoming Big Sagebrush After Four Treatments

Long-term recovery of Wyoming big sagebrush (Artemisia tridentatassp.wyomingensisBeetle and Young) after four treatments was investigated. Treatments at a south-western Montana site were spraying with 2,4-D, plowing and rotocutting, all applied in 1963, and burning applied in 1964. The treatments and an experimental control (no treatment) were replicated four times. Sagebrush canopy cover was determined after treatment for each of 10 years from 1964 to 1993. Temporal differences in sagebrush recovery among treatments were estimated. Burning had the longest-term effect on sagebrush cover, but growth eventually returned to levels not significantly different (P0·025) from untreated areas. The other three treatments exceeded untreated levels over the long term. Sagebrush that was sprayed, plowed and rotocut equalled the untreated areas after 18·1, 10·4 and 18·1 years, respectively. The exclusion of grazing for 30 years had no effect on sagebrush canopy in the untreated plots. Our findings clarify successional trends following disturbances in Wyoming big sagebrush habitat types. This information should enhance management opportunities of this important vegetative type for a variety of resources.