Deer Culling At Valley Forge National Historical Park Leads To Better Forest Growth

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A significant reduction in white-tailed deer has led to a boom in native species tree seedlings at Valley Forge National Historical Park/NPS

Dogwood. Black Gum. Sassafras. These are just some of the native species seedlings that have been spotted in the forests of Valley Forge National Historical Park, where a significant reduction in the white-tailed deer herds has allowed these trees to recover from overbrowsing.

Preliminary data indicate an increase in the number of seedlings of 850 percent through the first four years of the implementation of the deer management plan, park officials say.

"Park staff and visitors continue to report native trees, shrubs and wildflowers parkwide. It's exciting to see the forest recover," said Kate Jensen, the park's ecologist.

The sightings indicate that the deer management plan is beginning to achieve its objective of allowing the native forest to grow and mature so it can provide habitat for a range of native wildlife species, a park release said. The increasing deer population over the last two decades and the pressure of overbrowsing had eliminated regeneration. No seedlings outside fenced areas had been left uneaten, the release added. The absence of vegetation had led to elimination of habitat, soil erosion, and the spread of exotic invasive species.

In March, the park completed the fourth year of plan implementation. Park staff worked with the United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services on eight nights between November and March to remove 116 deer from the park through sharpshooting. A total of 3,403 pounds of meat was donated to the Central Pennsylvania Food Bank and provided to food pantries, soup kitchens, and other organizations across 21 counties in Pennsylvania.

The estimated deer density in the park will be 49 deer per square mile (260 deer) after fawns are born this spring. Although still above the plan's initial target level of 31-35 deer per square mile, this represents a significant reduction from the estimated 241 deer per square mile (1,277 deer) present in 2009, park officials noted.

The number of deer removed in future years will be based on the results of annual spring deer population monitoring, updated calculations of deer reproductive rates, and forest health monitoring. This summer, park staff again will count trees within long-term monitoring plots to assess progress toward the forest regeneration goal of 8,079 tree seedlings per acre.

The park will continue to use lethal reduction until the initial target deer density is achieved or forest regeneration reaches its target. Once the target deer density or adequate forest regeneration is achieved, and once an acceptable reproductive control agent becomes available, the park will use reproductive control to maintain the target deer density level.