Wambolt et al. compared vegetative and reproductive growth characters of 10 bitterbrush (Purshia tridentata Pursh) stands on, and near, the Mount Haggin Wildlife Management Area, in southwestern Montana, in relation to browsing levels. At the 8 browsed sites, the browsing level ranged from 23-60% removal of all current annual shoot growth. Bitterbrush plants exhibited both twig-level and plant-level responses to browsing. Total bud density per plant was similar for browsed and unbrowsed sites; however, total bud density did differ at the twig level between browsed and unbrowsed twigs. No significant relationship between browsing levels on browsed plants and bud densities was found. Although browsing levels were statistically the same for the burned and unburned sites, flower bud density was lower on the burned site than on the unburned site. Overall, authors found only minor variations in the characteristics measured among browsed, unburned sites or between the 2 unbrowsed sites. However, this data indicate a fundamental difference in bud allocation patterns between browsed and unbrowsed bitterbrush plants and suggest that plants protected from browsing for many years should not be used as a standard for comparison with plants exposed to normal browsing pressures.
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