Digging up over ten millennia of mud from the region’s lakes and Great Ponds, a team of scientists have found that native people in coastal New England rarely used forest fires for agriculture, reversing decades-old ecological theories about land management and potentially reframing the context of modern conservation practices.
The findings, published in a recent study in the science journal Nature Sustainability, have broad implications for the Vineyard, where organizations have long used prescribed burns and other land clearing techniques to maintain what they believed were historically open-growth landscapes. But data from the study suggests that European settlers — not Wampanoags — were the ones to clear land for horticulture with fire, meaning that it was only with their arrival some 400 or so years ago that the region’s blanket of old-growth forest started to give way to some of the Island’s now globally rare sandplains, healthlands and pitch-pine scrublands.
For the previous 10,000 years, climate, not humans, primarily altered the landscape.
According to David Foster, an ecologist and author of the study who lives part time in West Tisbury and serves as executive director of Harvard Forest, the secrets sealed in mud for millennia have takeaways for both the study of history and conservation.
“One thrust is, wow, this changes the way we think about history and people in the landscape,” Mr. Foster said, speaking to the Gazette by phone this week. “But it should also change the way we think about conserving the landscape.”
The two of course are related. For much of the past quarter century, land management and conservation practices on the Vineyard focused on the belief that the region’s abundant native population used forest fires and land clearing for horticultural purposes, leading to diverse habitats, like the Katama sandplains, and native species, like the cottontail rabbit. The theory gained widespread traction in the 1960s, and has been used by organizations like The Nature Conservancy to support burns for preserving the Island’s rare open-growth landscapes.
But in more recent years, the archaeological record started to tell a different story, contradicting the notion that native people drastically altered their landscapes for farming. Although studies found native people did farm corn, beans and squash when necessary, the rarity of those crops in archaeological surveys suggested that regions like the Vineyard were in fact so rife with natural resources that broad-scale land clearing was unnecessary. Native people instead adapted to their bounteous landscape — a heavily-forested landscape sculpted not by humans, but by climate.
In order to test the theory, Mr. Foster and his team of scientists from Harvard, Emerson and Binghamton universities decided to get their hands dirty, collecting 10 to 30-foot cylindrical mud samples from over 50 sites around New England. The mud, like rings in trees, could be used as a geological timeline, with every inch-wide layer representing a different sliver of the past 10,000 years. The scientists then analyzed the layers for pollen and charcoal samples, scouring each to determine the extent of forest fires and the species present. They then dated them with radiocarbon.
Testing locations included Black Pond in Aquinnah, Seth’s Pond in West Tisbury, the Lagoon Pond in Vineyard Haven and other coastal areas with known native populations. Mr. Foster said the Vineyard was integral to the study.
“The mud has been accumulating ever since the glaciers left,” he said. “By the amount of charcoal you can determine how frequently there are fires, and by the nature of pollen you can determine the type of vegetation.”
Combining archaeological data from the mud samples with two dozen intensive studies of vegetation, climate and fire history dating back to the Ice Age, the scientists found almost no correlation between eras of dense human population and increased fire presence, suggesting that the human — or anthropogenic — impacts on the landscape before European contact were limited. Pollen samples suggested that the now-rare old growth forests were commonplace for nearly 10,000 years, and left largely unaltered by the Wampanoags.
“The ecological story that there’s no evidence for people in the landscape is very consistent with the archaeological story,” Mr. Foster said. “They weren’t farmers, they were fishermen. They were living off of seafood, shellfish, deer and off of native plants.”
Mr. Foster said the notion that agriculture wasn’t a major aspect of native life shouldn’t simplify our understanding of indigenous communities, but should actually add complexity to an understanding that was primarily shaped through the written accounts of white colonists in the 17th century.
“This changes the way we view native people operating in the landscape, but it doesn’t in any way diminish their ability to cope with really challenging environments, and to live a very flourishing life without much agriculture,” Mr. Foster said.
Although the study confirms beliefs long held in the archaeological community, Mr. Foster suspected that it would turn some heads among scientists and conservators in other fields.
“It is groundbreaking in that there will be ecologists who will be extremely surprised to read this. And I think there will be conservationists who will be extremely surprised and probably concerned to read this, because some of it goes against what people have been doing,” Mr. Foster said. “But the archaeologists think it makes perfect sense.”
He said because the findings transform thinking about how landscapes have been shaped in the past, it should also transform how they are managed in the future, especially on places like Martha’s Vineyard. While the Island used to be dominated by old-growth forests, it is now home to a wide range of globally rare ecosystems that also need protection, meaning conservation practices should be analogous with the varied techniques that sculpted the land centuries prior.
“We should be conserving as much of the landscape as possible, and then managing it in diverse ways,” Mr. Foster said.
For areas of old-growth forest, such as at Seven Gates Farm, a historic landscape that spans West Tisbury and Chilmark on the north shore, it is best to leave the land unaltered, just as the Wampanoags did for millennia, the study suggests. For shrubland, heathland and sandplains, it is best to use the grazing and farming techniques of the colonial era. Mr. Foster felt the use of fires to preserve open growth pitch pine, like the state forest, were ill-advised because they are expensive and historically inaccurate.
Even in the short period since it was published last week, Mr. Foster has received controversial feedback on the study.
“I think it will be received in mixed ways,” he said. “I’ve got some people who were ecstatic, and some people who were really upset.”
But he said the importance of the study is how it integrates archaeology, climate science, and ecology — three fields that he said were paramount to understanding the natural world, and how to preserve it, moving forward.
“I think we need to be very humble, when we think of what we are capable of doing,” Mr. Foster said. “Climate change is incredibly challenging. The best solution is to maintain as much nature as we possibly can.”
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