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Tuesday
Jan292019

Old-Growth Forests: Back to the Future?

There’s no question that old growth forests are fairly uncommon, especially in the eastern parts of North America.

In a handful of generations European settlers turned tens of millions of acres of old trees into beams and boards and a thousand other things and the land that had grown them to corn and potatoes and other food crops.

There was some left, sure. And in some regions — New England in particular — the trees came back as cropland was abandoned. But old growth is still less than 1 percent of the landscape.

Now, a new book makes the point that, not only should we value the old-growth forests we have, and make sure we keep them around, but that we ought to protect tracts that aren’t protected already and put new knowledge of how old-growth ecosystems work to use re-creating old forests because, well, our changing planet can use the help.

Ecology and Recovery of Eastern Old-Growth Forests, published in 2018 by Island Press, was edited by Andrew M. Barton, a professor of ecology at the University of Maine at Farmington, and William S. Keeton, a professor of forest ecology and forestry at the University of Vermont.

Its 15 chapters, each written by one or more scientists — forest ecologists, research foresters, biologists — looks at an aspect of eastern old growth forest through the lens of the latest 21st century science. Topics include climate change, streams, invasive species, biodiversity and carbon sequestration. The book covers the landscape as well, from the bottomland hardwood forests and pine savannas of the deep south to the southern Appalachians, the central hardwoods, the northern forests of New England and the Great Lakes states and the boreal woods of Canada.

“The whole question of eastern old growth is important,” said Barton in an interview in the kitchen of his home in Farmington. “There isn’t that much, but there is more than I think we realize. In the Smokies, for instance, there are a few hundred thousand acres of old growth and if you include other forests that are kind of like old growth but that have some history of human disturbance, there’s a lot.

“But there are also ways that, if we do management right, we can have more old-growth in 50 or 100Andrew Barton years,“ Barton said. “It’s important because if you look at how much biomass is in old-growth forests, half of that is carbon. That forest is keeping carbon out of the atmosphere.”

Once scientists believed that a forest’s carbon-sequestration potential had been pretty much used up by the time it reached the old-growth stage, but that has been disproven, said Barton. “Bill’s (William Keeton) chapter shows that forests continue to keep up net carbon intake over time.” When first propounded several years ago, “that was a blockbuster idea,” Barton said. “The other thing that is so important about these forests is that they are going to provide refugia for animals that are vulnerable to climate change.” But “the challenge now is that there is not an uninterrupted landscape over which they can migrate.”

Forests have always been subject to change. Think about it: Maine was covered with a mile of ice 20,000 years ago. When that melted it took thousands of years for forests to get established. The various species of trees have changed and changed again over time.

They’ve been able to do that, said Barton, because they had space and time to recover. “Now we have taken those away from them.” Humans have cut and recut forests; fragmented the forest landscape; introduced new tree species, pests and diseases; and are now changing the climate in what, for a forest, amounts to overnight.

William KeetonThough the forests profiled in the book are different, they tend to face a similar suite of threats.

In a chapter on invasives and eastern forests, for instance, John S. Gunn and David A. Orwig conclude that climate change will increase the frequency of natural disturbances like storms, and those disturbances can in turn increase the threat of invasion by non-native plants. A warming climate will make it easier for pests to move, provide a longer season to mate, lay eggs and disperse, and increase their winter survival.

“Without question, invasive plants, pests and pathogens represent a significant threat to remaining old-growth forests and create challenges for efforts to restore old forest structure,” they write.

The bottomland hardwood forests of the deep South are vulnerable because of fragmentation, agricultural runoff, human tinkering with the regions’ drainage patterns, climate change and invasive species, note Loretta L. Battaglia and William H. Conner in their chapter on the old-growth floodplain forests.

In the pine savannas of the southern U.S. new science has revealed that these unique ecosystems are true old growth, not some sort of early successional ecosystems kept that way by fire. Yet it is fire that makes them the species-rich ecosystems that they are, and it is fire that is necessary to maintain them, note Robert K. Peet and his two colleagues.

Major challenges to doing so:  the savanna forests are fragmented, those that have been regularly burned are rare, and the difficulty in using fire to maintain forests surrounded by, or surrounding, homes and businesses. But it is possible, they note, to restore these forests, given our better understanding of how they work and “on-going initiatives are leading us in the right direction.”

Anthony W. D’Amato, Patricia Raymond the Shawn Fraver look at the disturbances — windstorms, wildfires and pests and pathogens — that constantly affect the forests of the northeast. They argue that our newly-informed understanding of the disturbance-recovery process in old-growth stands can help us improve management of forests for sustainable yield. Key, they said, is looking at the landscape as less influenced by huge stand disturbances that level take out large tracts and instead more frequent smaller disturbancesEast Coast Forest affecting fewer acres.

Continuing that discussion, Keeton and three colleagues say that using forestry techniques to accelerate the re-creation of old-growth forests from previously harvested ones, is possible. And given the characteristics of old-growth forests — prime wildlife habitat, clean water, carbon sequestration — that thy provide, worth the effort.

Purists might disagree, but “In the Anthropocene, the idea of just letting nature take its course no longer seems to be an adequate strategy if the goal is to maintain biologically diverse and healthy ecosystems that function in a similar way to forests in the past millennium,” they write. But they note that, given all the changes at play on the land, restoration won’t be easy. Worth it, but not easy.

Taken together, Barton says, the book as a whole suggests “that a combination of protecting current old growth, allowing some areas to revert naturally, and managing some tracts to accelerate their development have the potential to greatly increase the amount of old-growth forest in the future.”

If our goal, however, Barton said, is to restore the forests of North America to some pristine state in the past well, good luck with that. Too much has changed.

“If we want to re-create a landscape completely untouched by humans, that’s not going to happen,” Barton said. “But if we want to create a landscape less influenced by humans, with the vital functions, characteristics, and biodiversity of old-growth, we can. That’s the way we have to think about old-growth in the future.”

Barton said another lesson that comes across in the book is that we just can’t bring back old trees, we have to bring back the other elements of the forests, from the fungi to the invertebrates to the insects and microbes. And that’s a lot of ecosystems. There are half a dozen different types of pine savannas alone in the southeast, each with its own mix of trees and understory plants and animals, yet all depending on frequent fires.

Fall in the East Coast“It’s not like we can just untether ourselves from the ecological or biological history of these forests, we cannot,” said Barton. “But we have to accept that, over every inch of the planet, there is no such thing as pristine anymore. For instance, every plant is experiencing higher carbon dioxide levels than they did 20, 50, 100 years ago.”

Ecology and Recovery of Eastern Old-Growth Forests is not an easy read. It’s fact-dense and filled with scientific jargon, written in the style of science journal articles, with fine-print citations at the end of each chapter that sometimes cover four or five pages alone. The audience is not necessarily the layman, though a woodland owner, old-growth fans or forest lovers will find it fascinating. Barton said the book is directed toward ecologists, professional foresters, conservationists, policymakers, and general readers with a zest for forest science. It’s may be too much to hope that senators and congresspeople will read it, but maybe some of their senior aides will pick it up, and maybe, somehow, its lessons will get translated to the landscape. Because when it comes to restoring the old-growth forested landscape science isn’t enough, Barton acknowledges — there has to be a political will to do it.

The benefits of old-growth forests are immense. Ecological services aside, perhaps the greatest is that they are psychologically uplifting. They renew our spirits. Few are the people who can stand in the presence of old trees, in an old forest like Maine’s Big Reed Forest Reserve or the Joyce Kilmer Memorial Forest in the Smokies and not be moved by the sheer agelessness of the place. It helps put the big-brain wizardry of the johnny-come-lately naked apes who dominate the planet in perspective.

Barton said old-growth — any old-growth forest — instills in him a combination of calmness and inspiration. “It has a big impact on me,” he said. “Maybe it’s something about continuity . . . that these trees have been around for a long time.”

In the last chapter of the book, Keeton and Barton write that “in some ways old-growth forests are timeless, on the one hand increasingly displaced from their past, yet having the opportunity to adapt to the future.” In the East, they say, it is a reminder of our shared history and the “complexity, messiness and grandeur” of the forests that once covered the landscape by the millions of acres.

Quoddy Head State ParkThe scientists who contributed to Ecology and Recovery show that, not only is old-growth still relevant, they write, but they may be “vital to our changing world” and that there’s a chance that, thanks to modern science, we can bring back more of that messiness and grandeur and complexity to our landscape, with benefits for humans, other species and the planet.

“With care and attention, future generations will be able to have the experience of walking into an eastern old-growth forest and perhaps they too will catch a glimpse of something timeless, mysterious and compelling.”

 

Joe Rankin writes on forestry, nature and sustainability for websites and magazines. He lives in New Sharon.