In the summertime, urban trees are at their most beautiful. But few things planted in the city can be as destructive. Summer storms can bring out their killer instinct. The dangers are evident just steps from my home, leading me to ask: "Can city folk coexist with the trees they love?"
I live on Barnaby Street in Washington, D.C., in a mini-neighborhood called Barnaby Woods. There's a reason for the name: huge oaks and maples scrape the sky here. They reach across the street in a warm embrace and create a forest-like canopy. Or at least they used to.
In recent years, many of the giants have tumbled from their lofty perches. Old age, storms and disease have exacted a heavy toll on even the strongest. Arborists say that when they survey neighborhoods after storms, it's often the healthiest trees that have fallen. They just happened to be in the wrong place and got slapped with an unimaginable wind load.
Forces Of Nature
Earlier this summer, I stood on my block with Keith Pitchford, a local arborist who hadn't been to my street in three years. He was amazed at how many trees we'd lost.
In 2005, Pitchford helped me and my neighbors save some of those trees from the hands of Pepco, the local power company. Pepco wanted to cut down about a dozen bad actors, trees that kept rubbing up against power lines, causing regular blackouts. Utility company arborists said the trees were diseased and doomed to die. We proved otherwise and saved many of the giants. We won that battle — but we lost the war. Now, the forces of nature are destroying what we had managed to preserve. Pitchford looks up and down the block.
"We're looking at the end of the climax forest age, where the bigger trees are starting to die and fall, and the younger trees are coming up," he says.
There's no denying what Pitchford says. The shade garden I planted in the front yard is getting burnt to a crisp since the demise of a sugar maple and a red oak that used to protect our house. The problem is that the next generation of trees the city is planting won't cast the same shadow as the old ones. Why? To protect the power lines.
Competing With Hot Wires
On a corner in Northeast D.C., Pepco arborist Nathan McElroy supervises a crew of contractors who are pruning some scarlet and willow oaks that reach dangerously close to the power lines. McElroy is trying to keep the main trunk of the tree from growing through the lines. That means the utility has to come back over and over to maintain the same trees. If Pepco falls behind, the result can be deadly.
McElroy pulls a couple of stumps of wood from a little cloth bag. He shows me charred tree branches. It's what happens when trees get too big for their britches and start to compete with those hot wires.
I've seen where this can lead. Twice, a big tree in front of my house caused the power line to snap. A live wire danced on my front lawn for many uncomfortable minutes, spewing sparks like a fire hose. The thing was so hot, it turned soil into glass. That's why Pepco and other power companies are so passionate about trimming trees often, and taking down those that get out of hand.
"We do not look at the tree as something we are trying to harm," says Pepco spokesman Clay Anderson. "Safety is a prime concern."
Proper Tree, Proper Place
Utility people say they can't win. If they trim too aggressively, residents, like me, complain that they are destroying the canopy in an old neighborhood. But if untrimmed trees take out power lines during a storm, those same residents jump on the phone and demand that the utility turn the juice back on right away. Earl Eutsler is a District of Columbia arborist. He says there's only one way to solve the conflict between trees and power lines.
"Planting the proper tree in this space. For example, the amur maple we installed in front of your house," he explains.
"Proper tree, proper place" is the motto for the city's plan to replace tall trees under power lines with species that are more, shall we say, cooperative.
Eutsler takes me for a drive in his natural gas-powered car to show me what this might look like. He points to a series of purple leaf plum trees, planted in the "tree box," or curbside plot along the street, where stately elms used to stand. The new trees are "starting to establish themselves," Eutsler says. "These here that are already 15 feet are going to get another 10 feet tall, and that's really it," he says.
"But they're not really providing shade," I counter, staring at a perfectly respectable stand of trees that will never soar or form a graceful allee, "Not in the sense you can go out and sit with your neighbors under a tree like that."
"No, you're right," says Eutsler. "But it's more manageable, it's less dangerous."
City foresters encourage residents who want tall trees to plant them closer to homes, but away from the power lines. Despite my love for big trees, I'm not too crazy about having them right next to the house.
Many cities are moving in the direction of shorter trees under power lines. Phoenix, for example, recently inventoried 17,000 trees, of which 12,000 were found to be "problem species" threatening the electric grid. They will gradually be replaced, with the right tree in the right space.
Room To Roam
Power lines are not the only threat to the great trees of Washington and other cities.
"Curb and sidewalk replacement is probably the No. 1 enemy of urban trees. It just does more damage to the roots of these big trees than anything I can think of," says Pitchford. "And even when sidewalks and curbs are left alone, they form a barrier that keeps tree roots from expanding the way they want to."
When a neighbor's house was nearly destroyed by a fallen tree recently, I marveled at the enormous root ball. But even more amazing was the shape of that root ball: It was a strict rectangle. The roots had been unable to penetrate the tiny boundaries of the tree box created by the sidewalk and curbs. Arborists say that makes these trees less stable and more likely to topple in a stiff wind.
Some cities are investing in "structural soil" that gives tree roots room to roam. The soil can support the sidewalk, without being compacted down into a barrier that crushes tree roots. It's more expensive and more trouble, since the soil has to be specially prepared.
But Eutsler says cities should consider this when they are rebuilding older sidewalks and planting new trees. Streets around D.C.'s Dupont Circle have been rebuilt using structural soil.
Many residents ask why power lines can't be put underground, to forestall the inevitable conflicts between trees and wires. Pitchford says that's certainly a possibility for new neighborhoods. But he points out that undergrounding requires a lot of digging, and in established neighborhoods, that inevitably tears up tree roots. So it's not a realistic option in older neighborhoods like mine.
Pitchford says it's inevitable: Cities will start replacing big trees near power lines with smaller species. He wishes it weren't so. Me, I can't help myself. Sometimes I go up to the puny amur maple the city planted in place of my old red oak, and I whisper: "Think big."