Lexington's urban forest is in serious decline, forester Tom Kimmerer says. Culprits include insects, disease and climate change. But, mostly, we are to blame.
"Our basic philosophy has been plant 'em and kill 'em," he said. "We spend a lot of money planting trees, then we kill them through neglect and abuse."
Kimmerer has a doctorate in forestry and biology. The former University of Kentucky faculty member now does consulting work on woody biomass for renewable energy projects.
After watching Lexington's treescape decline over the past decade, Kimmerer decided to donate a lot of his free time this year to figuring out why. After much study, he produced a succinct report (download at Kimmerer.com) that identifies problems and offers simple and affordable solutions.
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The report notes that 85 percent of the trees planted in Lexington parks and along roads have been heavily damaged by poor planting or maintenance. City government employs good arborists, Kimmerer said, but there is no unified urban forest management plan, system or structure.
After Kimmerer sent a copy of his report to Mayor Jim Gray last month, city officials responded quickly to make changes.
"I think what he did was terrific; it gives you an ah-ha moment," said Jerry Hancock, director of Parks & Recreation. "We're hopeful we can immediately and greatly reduce the amount of damage being done."
But this is not just a government problem. Kimmerer said homeowners, developers and commercial property managers often know little about planting and caring for trees. (Among the exceptions, he said, is Hamburg Pavilion shopping center, which is doing an excellent job.)
Kimmerer said urban and suburban Lexington should have about 50 percent tree canopy cover. But it is now only about 20 percent after a decade that included two major ice storms and several droughts.
Insects and disease have killed pin oaks and are now killing ash trees. Both will soon disappear, just as once-plentiful elms and chestnuts did early in the last century.
Within many of our lifetimes, a rapidly warming climate will cause once-plentiful species — including sugar maple and yellow poplar, the state tree — to disappear from Kentucky.
"We need to be planting a mix of what does well now and what we expect to do well in a warmer, more drought-prone city, " Kimmerer said. He added that a healthy urban tree canopy is not just about beauty; it significantly reduces the effects of hotter summers.
We can control Lexington's biggest tree problems at little cost, Kimmerer said. On a beautiful frosty morning last week, he took me around town to see examples. We went to parks, neighborhoods, shopping centers and road medians. The issues were similar:
■ Trees planted in poor or compacted soil. This was especially true in road medians and shopping centers, but also in subdivisions built after the 1960s. That was when developers started doing a lot of grading with heavy equipment, which buries rich topsoil and compacts the ground.
■ Expensive trees planted, then not watered regularly. Kimmerer also pointed out "mulch volcanoes" around tree trunks. A little mulch is good; too much is deadly.
■ The biggest problem is mower damage to young tree trunks, which splits bark and dramatically shortens tree life. Plastic tree guards don't help much. "I call them mower magnets," Kimmerer said.
Tree damage was especially apparent in parks. Mowing contractors' low-bid work gives them incentive to mow as quickly as possible with big equipment, and damage often goes unnoticed. More contractor supervision and accountability would help, Kimmerer said, but so would changing our mowing philosophy.
As with streams, trees stay healthier without close mowing. Wide, shallow mulch circles can help keep mowing machines away. But so can simply allowing a little tall grass around tree trunks, especially in places where trees are planted close together.
With tight city budgets, Lexington must raise the level of citizen awareness and engagement on tree issues, Kimmerer said. Neighborhood groups and interested individuals could be trained to care for trees in their own yards, as well as to spot and report problems in their neighborhoods and on public land.
"We need an urban forest management plan," said Susan Bush, director of Lexington's Division of Environmental Policy, adding that work on one has begun. "That's at the root of some of the issues we're dealing with."
Bush also liked the idea of more citizen involvement, and she has already begun work on it. One effort will come next year with a citywide survey of street trees.
"I think he has some good ideas," Bush said of Kimmerer. "I'm glad he was willing to help us."