the allegheny front

Impacts of White-Tailed Deer on the Ecology of Pennsylvania

Ann Murray

Air date: 05/10/2006

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A growing list of scientists says that hungry deer are driving the ecology of Pennsylvania forests. Forest observers say that in many parts of the state, it's been a very bumpy ride. The Allegheny Front's Ann Murray has the story. The first in our series about deer management in Pennsylvania.


[WALKING THROUGH FOREST]

Dr. Susan Stout, a researcher with the US Forest Service, has been studying deer impacts on forestland for the past 15 years. Today, she's looking at a managed oak forest in northwestern Pennsylvania.

STOUT: These are the key characters in our drama.

Stout points to a handful of oak seedlings growing on the forest floor. The six-inch trees are dwarfed by a sea of lime green ferns.

STOUT: Where deer are eating away the raspberry and tree seedlings, you end up with these carpets of fern under which it becomes so dark that tree seedling and raspberries can't survive or grow anymore.

Stout and other scientists say this isn't an isolated scene. They contend that an overabundance of deer has threatened the health of 100s of 1000s of acres of Pennsylvania forestland.

Bob Frye, author of an upcoming book about deer management, says the current deer scenario began with good intentions. By the turn of the 20th century, widespread logging and unregulated hunting had nearly wiped out Pennsylvania's deer populations. Hunters and the new game commission shipped deer from Michigan and Virginia into the state. Frye says sportsmen and wildlife managers became protective of the fragile, new herd.

FRYE: If you protected a doe, one deer in the fall might become three deer in the spring. So wildlife managers and hunters agreed it was key to not shoot does. It became like a sacred animal.

By the 1920s, the population had rebounded with such vigor that there were already warnings about deer impacts on Pennsylvania land. By the 1980s, the herd in the northwestern counties peaked at more than 50 deer per square mile. According to Gary Alt, populations are now low there because food is scarce. Alt blames the Pennsylvania Game Commission for allowing generations of deer to overwhelm their habitats. He served as the commission's chief deer biologist from 1999 to 2004.

ALT: This is not just a hunting problem. It's not just a deer problem. It's a major ecological issue that has enormous consequences.

Most foresters agree with Alt. They say that hungry deer are eating the seedlings that should replace Pennsylvania's aging forests; forests that were planted 100 years ago and are fast approaching the end of their life cycles. A US Forest Service inventory indicates that half of the harvested trees in Pennsylvania aren't regenerating. Separate studies link deer impacts, harvest methods and available light with regeneration problems in areas of the state.

[NATURAL SOUND OF COOK FOREST]

Deer are impacting old growth stands in Pennsylvania, too. Gary Gilmore, a state forester, says centuries old pine in Cook Forest State Park remain vulnerable.

GILMORE: The white pine are reaching the end of their maturity. They're going to start dying here within this century. And as they die without young trees to replace them - the forest will cease to be a forest.

Plant biologists are already seeing a loss of diversity in forests that have been over-browsed by deer. A ten- year study by the US Forest Service in Warren, Pennsylvania found that as deer densities increased, tree species, declined. Deer favorites like red maple, ash and poplar were reduced. Native yews nearly disappeared all together. Research shows that loss of forestland can create a vicious cycle of erosion and run off. So foresters are keeping a close eye on forest regeneration and diversity now.

[TIM CARR DOING TREE INVENTORY]

CARR: Want me to swing this stick while you count or do you want to swing it? OTHER FORESTER: I'll just count the established ones first.

Tim Carr and two- dozen other state foresters are learning to inventory new growth on forested plots. Carr manages state forestland in the Pocono Mountains. He says inventories in his part of the state are driven by deer.

CARR: The deer have effectively halted the regeneration of our oak forests and have reduced most of the native shrubs and wild flowers in the Poconos.

Carr says this wholesale loss of low-lying vegetation is hurting deer and other animals such as grouse, songbirds and snowshoe rabbits. These animals depend on ground and mid-canopy plants for cover and food. The state has put up nearly 900 miles of fence on public forests to keep deer out. And has had success regenerating trees and shrubs inside deer exclosures.

CARR: Inside our fences we find dozens of plants that cannot be found outside the fence. And they haven't been found outside the fence in the last 30 years.

But the fences are expensive to install and maintain and only surround a fraction of Pennsylvania's 2 million acres of state forests. 15 million acres in privately owned forests remain largely unfenced because of the cost and owners' lack of understanding about deer damage.

Some hunters say all of this effort is for naught. They argue that liberal hunting laws have already reduced the herd size and that deer aren't the culprits in the battle to regenerate Pennsylvania's forests. Greg Levengood is chairman of Unified Sportsmen of Pennsylvania, a 40,000 member hunting organization that recently sued the Game Commission.

LEVENGOOD: We feel that there should be pH studies of the soil to determine whether or not desired plant species can even grow in our soils because we have such a tremendous problem in this state with acid rain.

The state Bureau of Forestry says while acid rain is a big problem in forest management, acidic soils slow but don't stop tree growth. The Bureau and a coalition of conservation and sportsmen groups want the game commission to do more to keep deer numbers in balance with their habitats. To that end, they're asking for more flexible hunting regulations and a broader based funding source for the Commission. Tim Schaffer directs Audubon Pennsylvania, a coalition member.

SCHAEFFER: Right now the majority of the Commission's revenue comes from hunter's license dollars. .. as a result, the pressure is there to let the numbers go back up because there's fear that that source of revenue will be eliminated.

Chris Rosenberry, the commission's chief deer biologist, says hunters don't set his agency's agenda.

ROSENBERRY: The Game Commission has a duty and a responsibility to manage all wildlife for all Pennsylvanians.

In 2003, the agency developed new goals to focus on healthy deer and habitat. It broadened doe hunting seasons and created programs to give landowners more ways to control deer populations on their land. Rosenberry says early indications are encouraging.

ROSENBERRY: We've heard anecdotal reports of regeneration. Individuals seeing plants they haven't seen before. All that starts to lead to the idea that deer populations have come down and forests may be recovering.

But many foresters and biologists continue to worry. They point to the Game Commission decision this year to reduce the number of permits hunters use to kill female deer. A step they see as a back slide into the bad old days of big deer numbers. Pretty much everyone agrees that this long running debate about deer and habitat is far from settled.

For The Allegheny Front, I'm Ann Murray.