Researchers Use Tree Rings to Reveal Centuries of Indigenous ‘Cultural Fire’ in Northern Michigan

The fieldwork, conducted May 21 within Wilderness State Park, is part of Setting the Straits on Fire, a three-year collaborative research project involving the Little Traverse Bay Bands of Odawa Indians (LTBB), Michigan State University (MSU), and the Michigan Natural Features Inventory (MNFI) through a cooperative agreement with the U.S. Fish and Wildlife Service.

The project aims to reconstruct the region’s fire history and better understand how Indigenous communities used intentional burns, which are often called cultural fire, to maintain travel corridors, encourage food and medicinal plants, reduce fuel buildup, and sustain red pine forests.

“This project is a model of collaboration between tribes, agencies, and universities to understand and empower human roles in sustaining ecosystems in the Great Lakes region,” said Adam Schubel, resident biologist at the University of Michigan Biological Station, which served as home base for the research team during the spring fieldwork. Schubel serves on the Steering Committee of the Obtawaing Biosphere Region (OBR) of northern Michigan, part of a network of designated regions of global cultural and ecological significance recognized by the United Nations.

Josh Cohen, lead ecologist for the MNFI, knelt beside a red pine stump charred on one side. To most hikers, it might look like an old remnant of a dead tree. To the researchers, it was an archive.

Cohen and the team cut a cross-section from the stump, revealing tree rings and resin scars — the hardened traces of past fires. Red pine, or Pinus resinosa, is especially valuable for this work because fire wounds cause the tree to produce resin that resists rot, preserving stories of past fires for centuries.

“Stumps are living relics from a past time,” said Mary Parr, a member of the Sault Ste. Marie Tribe of Chippewa Indians and a fire ecologist with MNFI. “They’re not just stumps. They’re cultural artifacts.”

Spirit Lake has long held cultural and practical importance. The Blueberry Plains were historically maintained for blueberry production by the Odawa. For generations, fire supported plants such as blueberries and medicinal species that thrive after burning.

“The Spirit Lake area has always been important to the Waganakisning community,” said Derek Hartline, conservation biologist for LTBB. “We had these stories from the elders about going there to harvest and burn for blueberries. And now, the stories we’re seeing left in the red pine forests show exactly that.”

Hartline said the 6-7 year cycle they’re seeing helps return the nutrients, clearing out the canopy and opening space for blueberries to grow.

A separate research site known as Nebo Trail has a distinct fire history different from what’s found at Spirit Lake, despite being located less than five miles north of Spirit Lake. It was likely burned as a pathway to keep the critical corridor open and clear.

However, cultural burning was increasingly suppressed after European colonization. Today, decades of fire exclusion have altered forest structure, increased fuel loads, and contributed to ecological stress.

Dr. Kurt Kipfmueller, MSU’s 1855 Professor of Tribal and Indigenous Forestry and Natural Resources, said the tree-ring record can help shift how land managers think about fire.

“Fire ecologist Steve Pyne once said, ‘You can either have fires of choice or fires of chance,’” Kipfmueller said. “For me, I would prefer fires of choice.”

According to the team, frequent, low-intensity fires can reduce the risk of catastrophic wildfires by clearing excess vegetation before it becomes dangerous fuel. They can also shape stronger, more resilient forests.

Parr said fire affects the hardness of red pine wood, while Kipfmueller noted that fire-created spacing creates an ecosystem where trees don’t have to grow as tall, making them less top heavy and more resistant to breakage.

The spacing created by the fires also creates landscapes where fungal diseases and pests have difficulty spreading. When the forest burns, only the stronger trees are able to survive, creating forests that are resilient both physically and biologically.

For the researchers, the work across the region is both scientific and cultural. Dendrochronology offers physical evidence of what Indigenous communities have long known through oral tradition: fire was not simply a destructive force. It was a tool of renewal, care and stewardship.

Cohen said the project also raises a larger question about whose knowledge is recognized.

“Why do we have to open up stumps to open people’s minds?” he said. “We’re doing all of this research to answer a question that could have been answered by asking community members. It has always been right there.”