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Individual Highlight

Long-Term Differences in Forests With Different Deer Densities

Deer browsing exerts top-down selection on plant communities, which over time ricochets back up the trophic web to affect insects and birds. Forestry Sciences Laboratory, Irvine, PASnapshot : Thirty years after a study on the effects of deer on forest ecosystems established new forest stands at deer densities ranging from 10 to 64 deer per square mile, Forest Service scientists found that tree species diversity, canopy foliage density, insect density and bird density, all decreased significantly as the deer density at stand initiation increased. If deer densities were high initially, the effects carried over, even if densities were lower later.

Principal Investigators(s) :
Stoleson, Scott H. Ristau, Todd
Research Station : Northern Research Station (NRS)
Year : 2011
Highlight ID : 315


In a large-scale, 30-year controlled experiment, Forest Service scientists found that 10 years of different densities of white-tailed deer created contrasting forest tree communities with effects that ricocheted up the food chain even 20 to30 years later. Higher deer densities during stand initiation resulted in significantly reduced diversity of tree species, and density of canopy foliage, canopy insects, and birds, even thirty years later. Because recruitment of trees from seedlings to the canopy occurs over a relatively brief, early period (for about 10 years) these results show that even short-term variations in deer density may cause centuries-long disruptions to forest ecosystem structure and function. As numbers of predators decline and herbivores increase worldwide, similar effects may persist long after herbivore density becomes effectively managed.

Forest Service Partners

External Partners

  • Pennsylvania Department of Conservation and Natural Resources, Bureau of Forestry and Pennsylvania Game Commission
  • Seneca Resources
  • Timothy Nuttle and Ellen Yerger, Indiana University of Pennsylvania