Editor’s note: “Facing climate change” is series about the impact of global warming on Vermont’s people and environment.
Robert Turner isn’t panicking. He sees more foreign species invading our forests, more dying and downed trees and a shorter winter logging season. These are all things that could be attributed to climate change. But he’s not panicking.
“It’s hard to talk about these things without feeling like the sky is falling,” Turner said. “I think that there are reasons that we as a society and culture ought to be talking about these things. But we’re not in a panic situation by any means.”
That’s because Turner’s profession, forestry, tends to take a long view. When you won’t live to see the crop you planted this year harvested, perspective is a necessity. Turner, an independent natural resources consultant, says foresters have a lot to learn in a changing climate, but because they’re used to changing forests, they’re uniquely prepared.
“We like to think of our learning as adaptive kinds of learning. We try something, and we learn from it, and we change because of what we witness. And that’s certainly going to continue because the changes are going to come faster.”
Sandy Wilmot, a forester with the Vermont Agency of Natural Resources, has been spending a lot of time lately thinking about forests and climate change, a result of what she calls a “flurry of activity” in state government to prepare for climate change.
Wilmot says there are three main manifestations of a changing climate in Vermont: climbing temperatures (especially in the winter), intensifying winter rain and summer drought, and more frequent big storms.
“Each type of forest in Vermont is going to respond a bit differently to those impacts,” Wilmot said. “The species that are growing here in Vermont but are at the southern end of their range — in other words a lot fewer of those trees can be observed if you go south from here — those are the species that will be most affected.”
The cold hardy species that will be most negatively affected include balsam fir, red spruce and mountain ash.
“We expect in the next 40 years we will see a decrease in the abundance of those in Vermont,” Wilmot said. “We’re not sure how those changes will occur. It’s probably going to be a combination of current trees, full-grown trees dying back, some additional mortality and then the new regeneration of those species would also be affected as temperatures and climate on the forest floor change. So we expect to see changes in the amount of regeneration as well as the amount of these trees in the current forest declining.”
Even trees that are common and widespread in the Northeast, such as sugar maples, are predicted to die off in 100 years in Vermont if society doesn’t curb emissions.
Scientists also say indirect factors will also lead to dieoffs. Hemlock trees, common in Vermont forests, can handle warmer temperatures. What they can’t survive is the hemlock woolly adelgid, an insect that sucks a hemlock’s sap till the tree dies. The hemlock woolly adelgid has been moving north into Vermont as rising temperatures enable the pest to survive the winter and reproduce more frequently.
A number of Vermont’s most common trees are threatened by invasive insects. The emerald ash borer, which destroys ash tree species, is on the way. The Asian longhorned beetle, which kills sugar maples, is also closing in on Vermont from the south. This beetle, combined with a too-warm world, could ring the death knell for the state’s signature tree and the maple industry.
Invasive plant species are becoming more common as well. Common buckthorn, garlic mustard and honeysuckle colonize sunny areas in the forest and crowd out young trees seeking light.
“Invasives are not something that you can pin to climate change,” said Turner, “but you’re certainly seeing invasives in a lot of places that they haven’t been. They’re moving along quite rapidly.”
With more frequent, intense storms, more trees are blown down. These sunny gaps in forests support a diversity of wildlife, which is usually considered a good thing.
But, Turner said, “Certainly if we have larger openings as a result of blowdowns, birds come in, and they’re often bringing in the seeds of invasives.”
That’s why Turner is seeing more invasive plants in the interior of forests, far away from roads.
It’s not just tree species that are changing. It’s also the industry that relies on them. Turner said that in the forestry community, “There is a growing consensus that our winter logging season has been shortened by about three weeks.”
Foresters prefer to move heavy equipment onto frozen ground; in the warm rainy seasons the machines damage the fragile, local environment. But Vermont’s winters are getting shorter and warmer. Three weeks is a quarter of the three-month winter logging season.
Turner is worried about the long-term survival of forests in Vermont and the forestry economy that goes along with it. “I think that our society doesn’t realize how much industry is connected to forestry and as forests change the biggest impact is likely to be economic,” he said.
Turner says as the climate changes, people need to be pragmatic. He believes it is essential to plan for the impacts of invasive species by planting certain species in preparation for future climate conditions. “As managers and communities we have to think about what kinds of mitigation we can do, not just reducing our carbon dioxide emissions,” he said.
Oaks and hickories, for example, will likely replace maples and birches over the next few hundred years.
“Trees take a long time to grow,” Turner said. “If we started planting oaks because we thought oaks will do better than maples, we wouldn’t be able to do anything with those oaks for 40 or 50 or even 70 or 80 years,” Turner said. “As foresters we’re used to thinking like that, it’s not foreign to us to be thinking like that, but in the past we’ve mostly been dealing with the ecology of the trees in the forest. Now we’re dealing with outside factors that we have to consider.”
The uncertainty of future climactic conditions scares Wilmot. “Forests grow really slowly and you’re talking about a crop, if you want to call it that, that takes 80 or 100 years to grow,” she said. “I don’t know how we can anticipate how our future forests will look and I am just hoping that we feel our way in the right direction so that we don’t make mistakes along the way.”
Feeling out a path is exactly what the state is doing, Wilmot said. “Right now, we have really a flurry of activities going on having to do with climate change. At the Agency of Natural Resources there are planning efforts right now to increase the resiliency of a lot of different natural resources, and that would include forestry. I’ve been working on several projects with other foresters to develop some methods that we can use to slowly adapt forests to these changes that we’re expecting.”
These include figuring out how to keep current woodlands healthy by considering the requirements of each species and how they might respond to changes in the climate of the forest floor and interactions with other species.
Wilmot is working on recommendations for how to maintain a healthy forest for foresters at all scales, from the woodlot to the state level.
“It’s not going to solve all the problems. It is taking our current understanding and trying to use the best science possible to feel our way forward,” she said.
Wilmot looks to natural resilience for hope. “We are very fortunate that in the past our forests have regenerated themselves. They’ve adapted to a lot of different problems that have been thrown at them and have recovered in one way or the other. We’ve seen other species fill in those gaps left by species we’ve lost, and these new species provide all the wonderful services that we need of the forests. For example, the elimination of chestnuts in the forest. We rarely think of that anymore because other species have been able to replace them. So that’s my optimism.”
Turner has faith in people. “I think that the fact that we’re beginning to address some of these concerns openly gives me hope, that we’re talking about them not in a reactive way. I think it’s also important for professionals in natural resources to be talking about what we can expect and then engaging in that community conversation so that it’s not scary, and I think that’s happening.”