Can we make Vermont's forests more like old forests, faster?
Old forests are good for water quality, plant and animal and fungi life. Scientists also think they have a better shot at surviving climate change than younger forests do.
But in Vermont and New England, the climate is changing fast — faster than the national average.
And some scientists want to know: Can we make our young forests more like old forests faster, so they have a better chance of growing old?
The Catamount Community Forest in Williston is a maze of trails. In its former life, it was a dairy farm. The roughly 400 acres of woods here don’t feel very far from that.
Chittenden County Forester Ethan Tapper leads the way to a stand of trees that’s much more open than the scraggly pine forest around it.
“So what we did here was we took a forest that was this pretty even-aged stand of pines — about 90 years old — that regenerated in an old pasture,” Tapper said. “And by ‘even-aged’ I mean that all those pine trees were, like, the same age, basically, one canopy layer. And we left a lot of them as legacy trees.”
In this “teenaged” stand, they cut down smaller trees to create space for the ones they left to continue growing. And they left the cut trees to decompose on the ground.
The larger trees that are leftover will be allowed to grow old. The hope is that all this new space will make it easier for them to do that.
Over time, many forests would experience this sort of disturbance on their own. For example, a big wind storm might take out some of the smaller trees.
But by coming in with tools and machinery, Tapper says they can do in days what might otherwise take decades.
The goal is to make this forest have some of the things you might find in an old forest, like having a diversity of trees of all ages and species and lots of standing dead wood.
Scientists think this diversity will make forests better able to survive invasive pests, extreme weather and hotter temperatures due to human caused climate change.
“These forests are shaped by death, as much as by life. So they're shaped by these disturbances,” Tapper said. “If we use forest management in the right way, we can create these sort of simulation disturbances that can drive the development of those characteristics [on a faster timeline].”
The scientists also want to know what would happen if we just left the forest alone, to keep growing old on its own time. They’re testing that here too.
We walk to a control area nearby, similar to what the last stand used to be: all white pines about a hundred years old. Overhead, the canopy is very dense, so there’s very little growing in the understory.
It’s dark and quiet and beautiful.
But Tapper says in our changing climate, some of the qualities that make this stand of trees so striking also make it incredibly vulnerable to destruction.
“When we see a forest that’s dominated by a single generation of trees of a couple different species, I see that as a forest that’s extremely vulnerable,” he said. “They’re vulnerable to extreme weather events, natural disturbances that can be very destabilizing. They’re also vulnerable to invasive pests and pathogens.”
Climate change is already bringing new pests like emerald ash borer and beech leaf disease to Vermont.
"These forests are shaped by death, as much as by life. So they're shaped by these disturbances ... If we use forest management in the right way, we can create these sort of simulation disturbances that can drive the development of those characteristics [on a faster timeline]."Ethan Tapper, Chittenden County forester
Tony D’Amato is a silviculture professor at the University of Vermont who is leading the research at the Catamount Community Forest, along with similar research at sites around the state.
He says scientists understand pretty well what makes forests resilient to climate change, what helps them store more carbon or create more biodiversity. The hard part is knowing how to manage them to get there — where to intervene and how, and where to walk away.
“The bigger question is: Will we know what combination, you know, is best?” D’Amato said. “And that’s why I think we really need to be testing these things out.”
D’Amato’s research is part of an international effort to study ways to help North America’s forests adapt to climate change.
There are projects like the one at the Catamount Community Forest all over the country.
It’s the sort of research Kevin Griffin, a professor of physiological ecology at Columbia University, says is crucial right now.
“We can’t go back in time, because the climate’s changing,” he said. “So our goal shouldn’t necessarily be to recreate the forest of the past, but to think about what a healthy, thriving forest will look like in the future.”
Even if scientists can figure out a good formula to age forests faster, Griffin says there are some things that only time can repair. For example, this work won’t bring back the soil structure of old forests, or the fungi that once grew here overnight.
“An old growth forest is just a wonderfully magic place. So it’s a great goal,” Griffin said. “But of course, an old growth forest, its characteristics include things like mixed age and standing dead trees and canopy openings. And these are all very difficult things to create in a young forest.”
Some environmental activists in Vermont say we should avoid or minimize intervention on public lands — particularly when intervention means cutting down trees.
Last year, the old forest advocacy group Standing Trees sued Vermont’s Agency of Natural Resources over how it makes these decisions. The suit came after ANR announced plans to harvest timber and — regulators say — make some parts of the forest more climate resilient by cutting down certain trees in the Camels Hump State Forest.
“What’s the best way to be a responsible steward of the land? It’s an open question, I think.”Kevin Griffin, Columbia University
Most foresters and silviculturists in the state say leaving forests alone won’t work everywhere.
Griffin says this question of where to intervene and where leave a forest alone is very important and unanswered right now in the science:
“What’s the best way to be a responsible steward of the land? It’s an open question, I think.”
At the Catamount Community Forest in Williston, the researchers will be measuring all sorts of things beyond tree size — how much fungi there is, how much carbon and moisture is in the soil, as well as how birds and wildflowers are impacted by the work.
Ethan Tapper, the Chittenden County Forester, says if it works, this sort of project is something any town in the state could take on.
“What we’re doing is, you know, not just trying to make this forest more like an old growth forest and trying to … create those conditions actively, but also increasing its resilience by what we call risk spreading — not putting all of our eggs in one basket,” Tapper said.
That’s because one thing everybody agrees about in this conversation is that in 2023 — which is poised to be the hottest year globally on record — to fight climate change, we need to do everything we can to make sure our forests stay forests.
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