Long, Hard Winter Has Damaged Trees In Pennsylvania

Wednesday March 05, 2003

UNIVERSITY PARK, Pa. -- It Started In Late October, When A Mix Of Snow And Freezing Rain Covered Jack-o-lanterns, And It Has Snowed At Least A Little Most Every Day Since, Capped By A Presidents' Day Weekend Blizzard That Dumped As Much As 3 Feet Of Snow On Most Of The State.

The long, hard winter has taken its toll on trees across the state, according to a Penn State forest specialist. "Trees have been under assault this winter," says Rance Harmon, extension associate in the forest stewardship program. "The weight of snow and ice can cause branches and even the main stems of trees to bend, twist or break. The October storm was especially damaging because the leaves on many trees had not yet fallen, and the remaining leaves provided additional surfaces for snow and freezing rain to cling."

Homeowners and forest landowners can take steps to help trees and woodlands recover from winter storms, according to Harmon. But before assessing damage, it is important to consider safety. "Avoid venturing into a woodlot on windy days after a storm," he says. "Be alert for large, leaning trees and branches. Keep in mind that hanging branches can be especially hazardous."

Due to greater exposure to the weather, trees near roads or other open areas often suffer more damage than trees in the interior of the forest, so the total damage may look worse from a trail or road than it actually is. "A good way to judge whether a tree will survive storm damage is to look at the upper branches," Harmon says. "If less than 50 percent of the crown is damaged, the tree has a good chance of survival. But depending on the extent of the damage, the tree's growth may slow down while it recovers."

If between 50 percent and 75 percent of the crown is damaged, Harmon explains, the tree may survive. However, its wounds may provide entryways later for damaging insects and diseases, especially if large tops or large lower branches break, or if extensive areas of bark tear. If more than 75 percent of the crown is damaged, the tree has a low chance of survival. "Homeowners can consult trained arborists who can evaluate damage, remove dangerous trees and branches, and correctly prune trees to help them survive," he says. "Private forest landowners can consult natural resource professionals to assess damage to their woodland, mitigate dangerous conditions and recommend appropriate management practices."

While storms do damage and kill trees, most trees are resilient and survive even severe winter weather. Storms are one way that forests naturally thin themselves with time, Harmon points out. When storms and other natural and human-caused processes open holes in the forest canopy, more sunlight is able to reach the forest floor. The sunlight leads to the growth of small trees, shrubs, wildflowers and other plants near the ground.

This lush growth provides food within reach of many wildlife species. Different species of trees thrive in these sunny gaps than under the shade of mature trees, so the diversity of trees and wildlife habitat increases as small disturbances occur across the landscape.

"Branches that fall to the ground after storms provide tender twigs, buds and winter fruits that are within reach of small mammals, which in turn serve as prey for predators such as foxes, weasels and birds of prey," Harmon says. "Damaged areas of trees often lead to decay, which in time produces cavities that can serve as homes for wood ducks, bluebirds, woodpeckers, owls, chickadees, squirrels, raccoons, bats, mice and many other animals."

Trees and large woody branches that fall to the ground provide cover, foraging habitat, thermal protection and nesting sites for salamanders and small mammals. Harmon notes that 23 species of amphibians and reptiles take refuge in decaying wood in the northeastern United States, including box turtles, salamanders and snakes.

The Pennsylvania Forest Stewardship Program provides many publications about Pennsylvania's privately owned forestlands. For a list of free publications, call toll-free 800-235-WISE or contact the Forest Stewardship Program, Forest Resources Extension, The Pennsylvania State University, 7 Ferguson Building, University Park, PA 16802; or e-mail RNRext@psu.edu.

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EDITORS: Contact Rance Harmon at 814-863-0401 or e-mail rsh144@psu.edu.

Contact:

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