In Ice-Damaged Towns, A Difficult Choice On Trees

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A vicious ice storm that made Christmas week a nightmare from the Midwest to Maine shattered hundreds of trees at Michigan State University, where inch-thick layers of ice snapped thick limbs and trunks of stately towers that had stood for generations.
It was a distressing sight for a campus billed as an urban forest where scientists since the 1800s have kept records of every tree, where native oaks and maples coexist with exotic Siberian elms and Japanese pagodas. But amid the destruction, Frank Telewski saw opportunity and jumped into action with his tools of choice – not chain saw or ax, but tape measure and computer.
The biology professor and curator of Michigan State’s arboretum is teaming with experts in several states to study which kinds of trees best withstand ice and other severe weather, and ways of making them even less vulnerable.
The project could present communities with difficult questions of whether to give up on trees that have long been fixtures of their landscape, such as dazzling but weak ornamentals that beautify downtowns and boulevards, in favor of less spectacular stalwarts that can bear up under strain like a well-conditioned athlete.
“If we can do something to reduce the potential damage, it’s going to be a great service to the country – make us better prepared to survive these storms,” Telewski said while measuring a jagged-edged limb ripped from a white pine during December’s icy barrage.
Heavy snow brings its challenges every winter, but ice storms are especially ruinous. They snap power lines, leaving multitudes in the dark. Ice layers can boost weight on limbs by up to 100 times, shredding them or uprooting entire trees, a risk to life and property as they topple onto buildings and vehicles. Researchers say losses regularly exceed $225 million annually.
The just-concluded winter, in which ice storms wreaked havoc across much of the eastern U.S., may spur more city parks departments, subdivision developers and even individual homeowners to reduce future losses by planting different trees.
“Strike teams” of U.S. Forest Service and state experts have been pushing the idea with officials in storm-damaged communities.
“It really doesn’t sink in until a community has a storm and tries to recover,” said John Parry, a Forest Service urban forester.
A 2007 ice storm so devastated Norman, Okla., that enough debris was collected – at a cost of $6 million – to halfway fill the stadium where the University of Oklahoma Sooners play football, Mayor Cindy Rosenthal said. Trees are not taken for granted in that state, where much of the landscape is naturally prairie. Its loss of prized hackberries, pin oaks and other varieties, some more than 40 years old, was a blow.
“The storm was traumatic,” Rosenthal said. “Through the night, you would hear the trees cracking and breaking. You knew what was happening but had no idea how bad the damage would be until the next morning.” The state has given away nearly 7,000 trees for replanting, but it’s uncertain how long it will take to fill in the gaps.
The city is now making tough choices about trees. Absent may be ornamental varieties such as the Bradford pear, which many cities plant along downtown streets for their attractive springtime blooms, although they’re notoriously fragile. Another tree with a bad reputation is the silver maple, which is brittle but popular with housing developers because it grows rapidly.
Favored are lacebark elms because they are a native species considered resistant to drought as well as ice. Others recommended include the bald cypress and various oaks.
Some municipal officials question whether ice resistance should be such a priority.
In Springfield, Mass., city forester Ed Casey says factors like resistance to disease and pests are uppermost in his mind.
With ice storms, “You can have perfectly healthy trees that are structurally sound, have good strength capacity, and they can still be damaged,” Casey said.
Telewski, the Michigan State professor, insists that species selection can make a difference. His team’s research also suggests that pruning trees can provide the same benefits as exercise for humans, he said.
“Done properly, pruning can be almost like physical therapy, because now the branches may be able to move more in the wind and actually strengthen themselves,” Telewski said. “They build up more woody tissue.”
Making storms less costly isn’t the only payoff from cultivating hardier urban forests, said Pete Smith, program manager for the Arbor Day Foundation. Trees provide an array of benefits – from absorbing pollutants to providing shade that cuts energy costs – and the bigger the better.
“We want to plant trees that live a really long time,” he said.

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