Deer Damage After Foliage Falls

Pat Sesto

ALLIANCE REMINDS: DEER FORAGING MOST DAMAGING AFTER FOLIAGE FALLS 

By Patricia Sesto, Wilton Director of Environmental Affairs 

Each winter, after leafy lunches disappear, over-abundant deer herds do their worst damage to tree and plant life. More towns are planning action now with help from the Fairfield County Deer Management Alliance. 

The overpopulation of deer in Fairfield County has raised other concerns about human and environmental health in our region, as well. Many residents are aware of the direct correlation between deer herd size and the incidence of Lyme disease and of deer/vehicular accidents. Impact upon our ecology from excessive deer density, however, is the least recognized problem in the community. 

Dr. Georgina Scholl, Vice Chairman of the Alliance, stated “Residents have forgotten that it is not normal to look through the forest and see the rise and fall of our topography hundreds of feet out. The shrubs and saplings that once comprised the leafy understory used to block your view. Today, such lower areas look more like manicured parklands”. 

With each deer consuming approximately 10 pounds of vegetation each day, the forest cannot regenerate its vegetation fast enough to support 60+ deer per square mile. According to Denise Savageau, Conservation Director of the town of Greenwich, “This rate of consumption, coupled with very high densities, has lead to a loss in biodiversity of both plants and animals. It threatens the stability of our natural areas”. 

Deer have over-browsed the lower layers in our woodlands, leaving a park-like setting of mature trees with little or nothing below them. In a healthy forest there are three layers: a non-woody vegetation or groundcover; the understory comprised of shrubs and saplings; and the canopy, which is comprised of mature trees. Clearly, our forests are no longer healthy given the absence of the understory and groundcover. 
The absence of the understory affects the forest in three ways. First, the understory is partially comprised of young tree shoots. These are the trees which should eventually replace the senior members of the woodland. If we were to sustain a major hurricane, for example, many of the mature trees would be toppled. In balanced woodlands, there are young members poised to seize the opportunity to eventually close the canopy. 

Secondly, the selective nature of deer browsing is reducing the species diversity of the woodlands. For example, deer browse has significantly diminished the population of native species, such as young oaks through the consumption of acorns and seedlings. Likewise, we are at risk of losing many heavily-browsed native species from our natural woodlands. Excessive browsing on native shrubs, especially in winter, has also provided greater opportunities for monocultures of non-native invasive shrubs, such as winged euonymus and Japanese Barberry, to take hold, again reducing our biodiversity. In addition, native wildflowers have all but vanished from our woodlands in areas heavily browsed by deer. In a recent talk at the Mark Twain Library in Redding, wildflower expert Jack Sanders told the audience that he has been unable to find many plants that were once commonplace in various open spaces in the Ridgefield area. This includes lady's slipper orchids, hepatica, and Canada lily. He also observed that other plants seem much less common than they were. 

Lastly, our understory supports several bird species by providing nesting and food resources. When the understory is gone, so are the bird species. It is estimated that 5-7 songbird species are no longer found in our area due to deer browse impacts. All of these factors have contributed to a reduction in the biodiversity of our forests. 

Ken Dartley, Chairman of Wilton’s Deer Management Committee, in a town that is proactively addressing deer over population, summarized that “If the deer were just eating our gardens and landscape plants, I don’t think the town would seek to reduce the herd. The fact that there is a real threat to the health of our natural areas, town-owned or otherwise, has in part motivated a community response.” 

Throughout the region, many landowners have already accepted the fact that the most viable means of controlling proliferation of deer is through hunting in the fall season, and they are engaging trained hunters now.