New York (November 17, 2012) – As cleanup slogs on after Sandy felled about 10,000 trees in New York City, and New Jersey reported more than 113,000 destroyed or damaged trees, cities are already rethinking the role of tree maintenance and how to replant smarter for the future. Here’s a roundup of efforts in Wilmington, Delaware, New York City, and Philadelphia to better position trees and green spaces to get the most benefits while reducing potential dangers and energy interruptions in the very likely event of continued extreme weather.
Trees remain critical to a sustainable urban landscape. As cities look at how to better prepare for severe weather, Su Barton, ornamental horticultural specialist for the University of Delaware is suggesting planting more trees in the right places to mitigate the impact of storms. Research continues to show the important role urban forests play in controlling runoff and flooding, and decreasing water pollution. More: Trees help counter flooding from storm water
In New York and New Jersey as homeowners and public officials deal with cleanup, some tree care experts say the shocking force of the storm weeks ago might mean they should reassess where and how to replant.
“When trees go down that have lived a long life and been so beneficial, it’s terrible when they cause injury to people and property,” said Nina Bassuk, program leader at the Urban Horticulture Institute at Cornell University. “We have to replant better and do it smarter.” For example, a soil substitute can help trees extend their roots beneath pavement so maybe they can keep their balance in high winds.
“Some trees may have been planted where they shouldn’t have been and you have other infrastructure conflicts. You don’t stop planting trees,” said Bram Gunther, chief of forestry, horticulture and natural resources for the New York City Department of Parks & Recreation. The goal behind New York City’s campaign to plant one million trees is to help with environmental issues such as greenhouse gases, air pollution, and the urban heat island effect. More: Sandy uprooted trees by the thousands in NY, NJ
What can prevent trees from becoming dangerous is picking the proper tree and soil in the proper place with the right maintenance. If all these are in place, trees can more happily co-exist with utility wires. More: A tree doesn’t have to be dangerous
And finally, Scientific American gets down to the roots of why some trees come down when faced with storms—super and otherwise. While most trees remain upright, three experts explain the science behind falling trees, including “windthrow,” disease, tree species, drainage, and tree cover among other things.
A primary reason trees fall is “windthrow,” which uproots a trees. The trunk acts as a lever and so the force applied to the roots and trunk increases with height, so taller trees are more susceptible. And in many urban areas, trees that have been developed around have roots cut, crushed and torn in the process and making them also more prone to windthrow.
Trees and tree roots may also have decay, or past injuries which make the tree more vulnerable to high winds. And trees that uproot in the face of wind may also be growing in shallow or rocky soil, or they are not protected by other trees. More: Why Do Trees Topple in a Storm?