Ice Storms and Urban trees


Adapted from “Cities, homeowners need tree education” by Tom Kimmerer, Lexington Herald-Leader, Friday, March 13, 2009

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The last of the branch piles from the ice storm are gone from most neighborhoods, thanks to valiant work by Lexington sanitation workers, local arborists and Missouri loggers.

Why did we lose power and why did so many trees come down? Some people are jumping to the conclusion that we need to bury power lines, but the best solution for our future may lie in good urban forest management.

It is true that part of the blame for the storm damage lies in our antiquated power distribution system. We have allowed our power grid infrastructure to languish. Power outages cost the U.S. economy $80 billion per year.

Replacing our 20th century power grid with smart grids that can intelligently work around problem areas will eventually reduce the impact of storms. But smart grids will not solve our power problems unless we fundamentally change the management of our urban forests.

In the weeks since the storm, I have been examining trees in Lexington and other communities. I have looked at trees that fell down, that broke and brought down power lines, and that withstood the weight of ice and force of wind.

If the weight of ice is greater than the strength of the roots, the entire tree will fall over. If the weight of ice is greater than the strength of wood in a branch, the branch will fracture. If a tree is decayed, especially where branches meet the stem, branches or stems will break, or the tree will fall over. The vast majority of trees I inspected after both the 2003 and 2009 ice storms failed because of decay.

Tree decay is the result of neglect by property owners. Many property owners spend no money on tree care, and the result has been devastating. If every homeowner in Lexington spent a small part of their household budget on tree maintenance, most of the ice storm damage would not have occurred. Which is cheaper: a modest expenditure on tree care or having your power lines or roof destroyed?

In many cases, we simply have chosen the wrong trees. Trees along property lines are often species that are very weak-wooded and prone to breakage. Trees like hackberry and black cherry, allowed to grow into power lines and repeatedly hacked at by poorly trained utility workers, are going to bring down power lines and cause property damage. Large trees have an important place in our landscape, but only if they we choose tough species, keep them away from power lines and maintain them adequately. Property owners need to replace large trees under power lines with small trees and shrubs.

Urban forests provide enormous social and environmental benefits. The cooling effect of trees reduces energy consumption for houses by up to 30 percent. In Lexington, the shady Ashland neighborhood can be 20 degrees cooler than neighborhoods around Fayette Mall. Trees dramatically increase property values. In Portland, Ore., trees add $7,000 to sales price of homes and increase the value of Portland’s housing stock by $45 million per year. Yet tree maintenance only costs Portland $4.3 million per year.

We must not let fear of large trees overwhelm us after two big ice storms. Kentucky communities need tree management policies that favor large, durable trees where appropriate and small trees under power lines. Cities and power companies need to educate homeowners in proper tree care and maintenance.

Cities need ways to give landowners incentives to replace trees along property lines with smaller, well-maintained trees of appropriate species. Since this could completely eliminate the need for utility tree trimming, money could come in part from the utility right-of-way budgets.

Lexington and other cities should create a land management agency with responsibility for all components of urban forest management, including parks and street trees. Cities with integrated urban forest management do a better job because they view the urban forest as a whole, instead of as a patchwork of responsibilities.

The urban forests of most Kentucky communities are in very poor condition. Instead of spending huge sums of money to bury power lines, we should focus on creating a resilient urban forest that will not come crashing down on houses and power lines every time there is a storm.