VEGETATIVE RESPONSE TO BURNING ON WYOMING MOUNTAIN-SHRUB BIG GAME RANGES

Information on vegetative productivity and nutritive responses to burn ing in mesic, high elevation big sagebrush (Artemisia tridentata Nutt. ) communities is limited. We investigated the effects of 2 wildfires a nd 3 prescribed fires on current year's production of herbs and select ed shrubs for 3 years post-burn, and forage quality for 2 years post-b urn in high elevation big sagebrush habitats in southcentral Wyoming. Production of perennial herbs on burned sites averaged twice that on c ontrols, while production of annual herbs varied little 2-3 years post -burn. Burn-induced mortality of Saskatoon serviceberry (Amelanchier a lnifolia (Nutt.) Nutt. ex Roem.) was less-than-or-equal-to 15%, but a 6-fold increase in twig production more than compensated for plant los ses. Mortality of true mountain mahogany (Cercocarpus montanus Raf.) a nd antelope bitterbrush (Purshia tridentata (Pursh) DC) averaged 25% a nd 55%, respectively, but these losses generally were compensated by i ncreases in browse production. Crude protein content of herbs from lat e spring through early fall was significantly higher on burns for 2 ye ars post-burn. These results suggest well-managed prescribed burning p rograms have potential to improve May through September diets of large herbivores in southcentral Wyoming mountain-shrub communities.