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Speaking For Trees

After Isabel and before winter, arborists urge homeowners to act to protect trees.

Recent warm weather that pushed temperatures into the 80s left few residents thinking about winter storms. But Robert Corletta, Arlington County’s urban forester, is telling residents to prepare now to keep trees safe from inevitable snow and ice.

Corletta, along with cooperative extension agent Tom Tyler and arboreal consultant Lew Bloch, met with residents at the National Rural Electric Cooperative Wednesday, Oct. 22 to let residents know what they can do to protect trees from damage due to natural stresses.

“Although tree work is very expensive, tree removal is very expensive as well,” said Corletta.

Residents and county officials learned that lesson after Hurricane Isabel crushed the Commonwealth. In less than four days following the storm, workers from the Department of Public Works cleared over 400 trees or large limbs blocking streets and sidewalks. “Perhaps we failed in not properly planting and maintaining trees,” said Corletta.

Storm damage costs will fall heavily on private citizens as well. Countywide, 44 cars were flattened by falling trees, 46 homes sustained major damage, 147 more homes took minor damage. Estimated damage to private property in the county exceeds $20 million.

The ordeal prompted the forum, which gave residents tips on how to protect their trees from future damage, and how to care for trees that sustained moderate to mild damage during Isabel.

TASKS MOST IMPORTANT to tree care are among the easiest. “One of the best things you can do is to become a better observer,” said Tyler. Homeowners should keep an eye on trees and look for visible signs of decay. That includes knots or cankers caused by injury to the outside of the tree; mushrooms at the base; cracks; girdling roots that wrap around the tree trunk; and broken or torn branches that may not leaf next spring.

Even tree maintenance can cause problems. “Tree wounds never heal,” said Bloch. “Every time you trim a tree you are injuring it.” If the tree is healthy enough, it will grow a protective tissue to surround and isolate that decay so it doesn’t spread.

Tree trimming is still important. But it must be done the right way. The panel at the NRECA encouraged residents to hire only certified arborists for tree maintenance. They offered other tree-trimming guidelines: It’s never a good idea to trim more than one-third of a tree’s branches at once; and in a tree’s early life, it’s important to look for structural problems that can make it weak later on, such as splits that lead to co-dominant trunks.

It’s also important to know where to trim. “Topping” causes serious damage, while trimming too many low branches can make it more likely that a tree will become top-heavy and topple over during high winds.

Even healthy trees aren’t immune to problems. “The trees that uprooted [during Isabel] were, generally speaking, the healthier trees,” said Bloch. Large, leafy branches caught the wind like a sail would, he said.

IT’S ESPECIALLY IMPORTANT to provide good maintenance to the visible part of the tree, considering the difficulties Arlington’s trees face below the surface.

Although it was once suspected that trees’ root systems extended only as far from the truck as the branches do (creating essentially a mirror image of the tree above and below ground), experts now say a tree’s root system easily can extend twice that far. But in urban areas such as Arlington, few lots provide that much space for roots to expand.

Soil underneath roads and sometimes under houses is so densely packed that roots can’t penetrate. The restricted growth patterns leave many Arlington trees poorly anchored, so under weight from snow and ice, or during high winds, those trees are more likely to topple.