Tribal and state ecosystem management regimes influence forest regeneration

Wild ungulates such as white-tailed deer (Odocoileus virginianus) are highly valued wildlife assets that provide subsistence, economic and cultural benefits to hunters and rural communities. Yet, high density populations of these herbivores can contribute significantly to regeneration failures in a wide range of forest types. Pre-European settlement white-tailed deer densities were estimated to have been approximately 2–4 deer km−2, and similar densities have been recommended to balance contemporary forest regeneration and wildlife objectives.We studied northern red oak (Quercus rubra L.) regeneration on neighboring tribal and state forests where socio-cultural differences have led to distinct hunting management practices and subsequent differences in wildlife-plant interactions. Tribes such as the Lac du Flambeau Chippewa have kept deer populations relatively low on reservation lands through active hunting practices. We used an observational study approach to compare in situ ungulate herbivory under low (2–3 deer km−2) and high (>10 deer km−2) population densities. We measured northern red oak regeneration on tribal and state forests in two management unit types: contiguous stands of oak >15 ha in area and small residual “pockets” of oak <3 ha left by foresters as a source of seed and wildlife mast. Herbivory levels were significantly higher on state forests than tribal forests and were closely correlated with the density of larger seedlings, particularly in oak pockets. If herbivory levels are too high, even with adequate light, our results suggest that seedlings may not survive in densities sufficient to maintain northern red oak as a co-dominant species in mixed forests. However, when deer densities are kept at 2–4 deer km−2, our results suggest that northern red oak seedlings can survive beyond browseable heights in sufficient numbers for maintaining oak. Tribal lands can provide contemporary examples of longstanding low to intermediate deer densities and sustainable deer–forest relationships.