The Working Forest 
April 16, 2009

Misha de Ridder for The New York Times

Over the winter, David Foster wanted to cut down some trees. His neighbor didn’t want him to. Foster is the director of the Harvard Forest, a 3,500-acre experimental forest in the middle of Massachusetts. When you are the director of an experimental forest, people aren’t sure you should be cutting down trees. “We’re cutting an acre of forest, nonnative conifers,” he told me calmly on a day in February, while grabbing some snowshoes. A forest ecologist will tell you that if you cut down some woods — not all the woods, but some of them — a new forest will quickly replace them. There’s a joke in Massachusetts that if you forget to cut your lawn, you will have a forest. For an ecologist, tree-cutting can be a stimulus plan that actually works.

A diorama at the Harvard Forest museum depicts an old-growth forest on the edge of a pond. “You have to learn from nature,” David Foster says, “but you have to manage.”
This cycle of forest succession is an observation that Foster attributes to Henry David Thoreau; when Foster is walking in the forest, something he does a lot, he will spot some young white pine trees, for example, in a freshly cut field and say, “There’s Henry Thoreau for you!”

The forest is back in New England. It returned, counterintuitively, while the population increased: Massachusetts, the third most densely populated state, is on the Top 10 list of most forested states. The forest is back to what we think of as Thoreauvian levels, even though, as Foster will tell you, the woods had been cut down by the time Thoreau was writing. “When Thoreau wrote ‘Walden,’ ” Foster likes to note, “New England was at the peak of deforestation.”

Meanwhile, the forest no one knew existed is threatened, not just by the ax this time but by parking lots and housing developments. According to Massachusetts Audubon, between 1971 and 1999 the land considered developed increased to 24 from 17 percent of Massachusetts, while “wildlife habitat,” which is defined as forest, wetlands and open water, declined from 70 to 64 percent. The second chance to save the returned forest has concerned Foster for the past few years, and now a plan he helped develop, called Wildlands and Woodlands, or W & W, has been moving through conservation circles like an aggressive invasive species. It suggests preserving 2.5 million acres in Massachusetts, or half the area of the state, from development. As opposed to old-style conservation, which primarily establishes protected public lands, W & W proposes conserving large, aggregated chunks of private land. Radically, it proposes that the land stay in private hands, allowing it to be used for limited purposes, like logging or recreation, as a way to encourage land stewardship rather than strip malls. “This isn’t restricting development,” Foster says. “It’s directing it.”

Foster is an ecologist and an environmental historian — a paleoecologist — concerned with the long-term processes that have shaped the land, like fires, floods, 18th-century forestry practices and Colonial farming. Tall and lanky, Foster is often in fleece and jeans, a camera around his neck. He is always clicking: a photo of a 200-year-old hemlock tree, of evidence of the 1938 hurricane, of a stone wall in the woods that would have, in Thoreau’s time, been in a field, a field that time turned into woods. It can seem as if Foster is trying to freeze-frame the precise state of the New England ecology for future reference. On that February day, as he strapped on his snowshoes and set out the back door, he recalled the time he was chided by a group of colleagues on a train in British Columbia. He photographed all the clear-cuts, forest burns and dead trees while everyone else looked away. They dubbed him Dr. Death. “I said, hey, for me it’s all about dynamics,” he said, crunching onto a forest trail. “It’s all about change.”

The Harvard Forest, too, is about change. Established in 1907, the Harvard Forest resembles a regular forest, but snowshoeing through, you soon begin to notice the little yellow flags planted in a snow patch, the metal measurement bands around the trees, the fence around a stand of saplings to protect them from the moose that have come back to Massachusetts, not in stray pairs but in herds. Experiments are everywhere, visible and not: cables run underground to heat the soil in one patch of woods; in another, fans are being set up to blow hot air. “It’s a forest of many observations,” Foster said, pressing forward.

One particular observation — the one Foster is heading toward — has stunned even those deeply interested in forests. This same New England forest that people did not even know existed has been doing a better job of keeping carbon out of the atmosphere than anyone imagined.

“O.K., here’s Julian,” Foster said as we reached the foot of an industrial staircase seemingly built to nowhere, anchored to a pole that was once a boat’s mast. Julian is Julian Hadley, an ecophysiologist on staff at the Harvard Forest. “Watch the ice on the steps,” Hadley said as we climbed. Up at the wobbly top, the sonic anemometer, in concert with other instruments, measures the flux or exchange between the atmosphere and photosynthesizing trees — the inhale of carbon, called the uptake, and the exhale of oxygen and water.

The past few years of carbon monitoring at the Harvard Forest have shown that the so-called midlatitude forests of the United States (the forests stretching up from the Carolinas into New England and Canada and the Midwest) are reducing the global increase in carbon by more than 10 percent. The Northeast forest doesn’t hold as much carbon as, say, the Amazon. But the Harvard Forest has shown that the rate of carbon-holding is changing in surprising ways. When you balance out the carbon taken in and released, the Northeast forest retains two to four tons of carbon per hectare every year, in part because the Northeast, with relatively young trees, isn’t creating as much carbon in the form of decomposing trees and foliage. “The forest is growing and increasing its uptake of carbon,” Hadley says. In the East, in fact, as forests hold more and more carbon, the rate of new carbon storage uptake is surpassing the Amazon’s. Suddenly, with this new discovery, the forest of the East, back from devastation, is a big and important player in global carbon storage.

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