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Tue February 18, 2014
Can Science Develop Stronger Trees in Connecticut?
As United Illuminating continues revisions on its ambitious tree-cutting plan, a group of scientists at UConn is studying why trees fail, and how they can be made stronger.
When a tree fails (that's scientific jargon for "falls down") and knocks out your power, you usually have two concerns: when is my power coming back? When are they going to clean this mess up?
But have you ever thought about why that tree fell?
Mark Rudnicki has. He's a scientist at UConn who studies forests. "Trees that do fail," he said, "we need more information about these trees. How did they fail? Where did they fail? What kind of tree was it? Was it surrounded by neighbors? Was it all alone? Did it have root rot? This basic information about tree failure: nobody collects it. Everyone is -- after a storm -- really focused on getting the power back up, getting this mess cleaned up. And the data is literally chewed up in chippers."
That data is important. About 80 to 90 percent of power outages during storms are caused by trees that fail. What if scientists could determine why a tree fails, and how failure could be prevented? What if they could build stronger trees? That's the mission behind Stormwise, a tree and forest management program at UConn.
I met up with Rudnicki near the Fenton track of the UConn forest to check out his work. It was snowy and really cold. As we marched through the snow, we looked up and saw a long power line arching above us.
"This power line here goes down to the Fenton River," Rudnicki said. "It's one of the two rivers that supplies UConn its water." The line powers pump houses by the river, so it's an important power artery. To protect it, Rudnicki's team, which is led by Thomas Worthley, thinned out the edge of the forest, cutting back trees and branches near the power line.
It's not clear cutting. Actually, it's far from it. Rudnicki said his idea has more nuance, he wants to cut back some of the trees in an effort to leave more space for those left behind. "[We want ] to open this up," he said, "to get these trees to intercept more wind, [and] start moving more. It's that movement that sends the messages we need to grow stronger. We need to change our shape. Now the average wind loading has increased. Trees can't adapt to the extremes, but they do adapt to the average. If we increase the average, then when the extreme comes, their threshold of how much extreme they can handle is higher."
Got that? Basically, more wind equals stronger trees, which leads us to the next question. How long would it take to increase the average strength of trees in a roadside forest?
"That's really a very crucial question," Rudnicki said. "We don't know. That's part of what this research is. We're tracking this long-term. After we open this up, we're going to do just that. We're going to monitor these sway dynamics very carefully."
Rudnicki means "very carefully." Looking up about 40 feet, it was not only the Fenton power line arching above us; there was also an array of gizmos sticking to the trunks of several different trees.
Jenna Klinck, a master's student at UConn, said the tree sway gizmos are her project. "It is a box that pretty much measures the motion of the tree -- the change in angle of the tree," she said. The measurements are taken ten times per second, 24 hours a day, seven days a week. "I can then take that information to a computer," she said. "and re-plot it, and actually see how these trees are moving in real time, in the wind. I can see how much is this tree moving when there is wind. How far is it moving? What direction is it moving in? And then how is that changing after this thinning?"
Klinck said she's also observing how wind moves through the forest, comparing it with an adjacent open field. It's a lot of data. "We have a whole year of data before any thinning was done," she said. "So we have a great database to compare it to, how this thinning affected the trees."
More than a dozen trees are rigged, which means Klinck's data accounts for a lot of variability. "We have a wide variety of species," she said. "Different ages of trees. Different sizes. Also different locations along the edge. We can get a whole picture of how are the different species responding to these changes in the forest? How are different trees in different stages of their life responding? Are younger trees responding differently than older, mature trees? We have a really great variety of different trees being studied out here."
Stormwise scientists said the Fenton site will be monitored for years to come. The project plans to set up roadside trimming experiments near power lines around the state, tracking how trees respond to a bit more open space, letting their branches dance on the wind.