White spruce demography and herbivory by snowshoe hares measured along elevational gradients in Denali National Park I - Site Data

Treelines in Alaska are advancing in elevation and latitude because of climate warming, which is expanding the habitat available for boreal wildlife species, including snowshoe hares (Lepus americanus). Snowshoe hares are already present in tall shrub communities beyond treeline and are the main browser of white spruce (Picea glauca), the dominant tree species at treeline in Alaska. We investigated the processes involved in a 'snowshoe hare filter' to white spruce establishment near treeline in Denali National Park. Because multiple factors interact to influence browsing of spruce, including the hare cycle, snow depth and the characteristics of surrounding vegetation, we collected an array of site variables relevant to spruce-hare interactions in Denali National Park, Alaska. Site variables collected included elevation, landscape position, vegetative cover, and the density of white spruce seedlings, saplings and trees.