The reintroduction of fire and repeated burning are proposed as restoration tools and as a way to control fuels in dry western forests. These forests are also frequently used for livestock forage. Yet most prescribed fire experiments in forests exclude livestock, confounding application of experimental results. From 2002-2012 we have periodically examined vegetation response to repeated spring and fall burning (5-yr interval since 1997) and cattle grazing exclusion (since 2002) using four upland stands in the southern Blue Mountains, OR. Data were collected prior to seasonal utilization. We analyzed the cover of 18 plant groups using a randomized complete block split-plot repeat measures mixed model with season of reburn as the whole plot and grazing exclusion as the split plot. Fall and spring repeat burning (RB) had no effect on total cover, but grazing exclusion (GE) increased total cover (mean increase 6.6%). GE also increased the cover of 1) nonrhizomatous, non-N-fixing forbs, 2) rhizomatous forbs (only for fall burns), 3) sedges, and 4) non-resprouting shrubs (only when not burned). Total plant richness increased with GE, but only in areas burned in the fall. While neither GE nor RB impacted perennial grass density or cover, GE and fall RB increased maximum grass leaf height and flowing culm height, and fall RB increased flowering culm density. Fall RB did increase the cover ofÂ BromusÂ tectorumÂ andÂ CeanothusÂ velutinus. Fall and spring RB decreased sedge cover, and fall RB also decreased rhizomatous forb cover but only in areas open to grazing. While repeat burning may be reducing fuels, most native perennials are unresponsive and some are negatively impacted by the frequent reburning. Undesirable species like exotic annual greases are slowly increasing, but overall cover still remains low. In contrast, many perennial plant species are increasing (cover and richness) in response to grazing exclusion.
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