EFFECTS OF COMPETITION ON THE POSTFIRE RECOVERY OF 2 BUNCHGRASS SPECIES

The effect of competition on the postfire recovery of Festuca idahoens is Elmer and Agropyron spicatum (Pursh) Scrib & Smith, was examined un der natural conditions, Thirty plants of each species were exposed to fire applied with a portable instrument system that allowed precise co ntrol of fire temperature and duration, so that all plants received st atistically similar fire severity levels inside the meristematic crown region, Treated plants were subjected to different levels of competit ion by periodically removing all or part of the aerial biomass around a monitored bunchgrass plant, Soil water potential, soil temperatures, and plant productivity mere determined at monthly intervals during th e growing season for the different competition treatments, No signific ant mortality due to fire was observed for plants of either species, A lthough Festuca did show meristematic tissue damage after fire, regrow th that occurred within 15 days after fire was more rapid than for Agr opyron, Only Agropyron plants without competition reached prefire prod uctivity levels, Soil water potential was significantly more negative in plots with competition, Temperatures in the upper 10-cm of the soil profile were significantly higher in plots without competition, Compe tition reduced root production and also restricted aboveground product ivity by approximately 70% for Agropyron and 115% for Festuca, The cap acity of these species to survive fire appears to be related more to t he micro-environmental conditions created following fire and to their capacity to compete for available soil water, than to the direct effec ts of fire on plant tissues.