Effects of Simulated Ungulate Browsing on Aspen Characteristics and NutritionalQualities

摘要

Natural resource managers in Michigan were concerned about the effects ofungulate browsing on forest stand regeneration. Consequently, we investigated the effects of ungulate browsing on aspen (Populus sp.) stand characteristics and nutritional qualities with simulated browsing experiments in the Pigeon River Country State Forest (Pigeon River Forest) in Michigan from 1985 to 1987. Thirteen clipping treatments were conducted in replicated exclosures on bigtooth (P.grandidentata) and quaking aspen (P. tremuloides) clear-suts. Simulated browsing did not change the nutritional qualtiy of aspen browse with the exception of an increase in ether extract in clipped quaking aspen. Bigtooth aspen tree heights and number of twigs were reduced (P less than 0.05) by clipping intensities of greater than 50 percent. Browsing of this magnitude by white-tailed deer (Odocoileus virginianus) and elk (Cervus elaphus canadensis) is occuring on some bigtooth aspen clearcuts in Pigeon River Forest. These effects were not noted for quaking aspen. Bigtooth and quaking aspen can both tolerate fairly high browsing intensities; however, differences in effects were observed between the 2 species.