Factors affecting browsing by moose (Alces alces L.) on European aspen (Populus tremula L.) in a managed boreal landscape

There is considerable circumpolar concern regarding the regeneration of several tree species in the temperate and boreal landscape due to heavy browsing. We analyzed the risk of browsing on aspen (Populus tremula L.) at two different scales in a managed boreal forest in northern Sweden with one dominating browser in the system, the moose (Alces alces L.). At the stand level, we found that a high density of aspen ramets in connection to or surrounded by young forest (predominantly Scots pine Pinus sylvestris L.) attracted moose relatively more than aspen stands in mature forest and interior forest, respectively. If a stand was being used, a single aspen ramet faced the best chance of escaping browsing in a stand with a high density of aspen ramets, located far from arable land. This utilization pattern by the herbivores suggests that older forest may function as a temporal refuge for aspen regeneration in the managed boreal landscape, but this situation may change as remaining old forest stands eventually turn into young forest. Although cutting will favour aspen regeneration, our study highlights an apparent paradox, as the emerging aspen ramets will face a high browsing risk from attracted herbivores.