LONG-TERM RECOVERY OF WYOMING BIG SAGEBRUSH AFTER 4 TREATMENTS

Long-term recovery of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle 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 r eplicated four times. Sagebrush canopy cover was determined after trea tment for each of 10 years from 1964 to 1993. Temporal differences in sagebrush recovery among treatments were estimated. Burning had the lo ngest-term effect on sagebrush cover, but growth eventually returned t o levels not significantly different (P less than or equal to 0.025) f rom untreated areas. The other three treatments exceeded untreated lev els over the long term. Sagebrush that was sprayed, plowed and rotocut equalled the untreated areas after 18.1, 10.4 and 18.1 years, respect ively. The exclusion of grazing for 30 years had no effect on sagebrus h canopy in the untreated plots. Our findings clarify successional tre nds following disturbances in Wyoming big sagebrush habitat types. Thi s information should enhance management opportunities of this importan t vegetative type for a variety of resources. (C) 1996 Academic Press Limited