In the US, state and federal governments regularly fight wildfires that threaten people and property, but Alaska’s Yukon Flats National Wildlife Refuge recently began piloting a novel strategy: putting out fires to prevent climate-warming carbon emissions from being released from trees and soils.
As the first refuge in the US to use fire suppression to protect carbon, the Yukon Flats experiment comes with some unique challenges. Due to limited budgets and firefighting resources, refuge managers face difficult decisions around when and where to prioritize firefighting efforts — all while navigating scientific uncertainties around how different actions will impact carbon storage.
Now, thanks to a $500,000 grant from the Department of Interior’s Joint Fire Science Program, Cary Institute scientists will assist Yukon Flats refuge staff by providing scientific insights vital to decision making. Over the course of the three-year project, Cary scientists will map how carbon is distributed across the refuge’s forests and soils, identify areas at highest risk of burning, and help fill in other data gaps to inform fire suppression strategies.
“For the managers who are making these really bold moves, we wanted to back them up and give them more information about how different choices might pan out over the long term,” explained project co-leader Katherine Hayes, a landscape and ecosystem ecologist at Cary Institute. Other project leads include Cary forest ecologist Winslow Hansen, Cary landscape ecologist Jazlynn Hall, and Brendan Rogers, associate scientist at the Woodwell Climate Research Center.
“We have very few tools in the toolbox for managing carbon in remote landscapes,” said Jimmy Fox, the Yukon Flats refuge manager who led the development of the pilot project. “We’ve had to make assumptions based upon the best available science that's out there, since we don’t have the luxury of decades of data on carbon in Yukon Flats specifically. So this research is essential for us to better understand whether or not this pilot project is going to be an effective climate mitigation strategy.”
Protecting a carbon-rich landscape, human health, and more
Forest fires in Arctic regions don’t just burn trees. They can also threaten underlying permafrost — permanently frozen ground filled with partially decomposed organic matter that has trapped carbon for thousands or even millions of years. Across the Arctic, permafrost stores an estimated 1,700 billion metric tons of carbon. That’s about double the carbon currently held in our atmosphere. When permafrost thaws, it unleashes carbon dioxide and methane, which exacerbate climate change and cause more warming and more permafrost thaw in a dangerous feedback loop.
Fires make it easier for permafrost to thaw, because they scorch away the surface organic layer — live and dead or decomposing moss, mixed with other dead plant material — that normally sits on top of the frozen soil, insulating it from fire or warmer temperatures. Black spruce, a key tree species that has dominated the landscape for millennia, fosters the accumulation of the surface organic layer, keeping permafrost insulated. As boreal fires increase in size, frequency, and severity, black spruce forests don’t have enough time to regenerate and are instead being replaced by faster-growing deciduous trees, whose open canopies may not be so effective at shading and protecting the frozen soil.
And beyond carbon, fire managers and researchers are taking into account the many human health and cultural impacts of more frequent and severe fires in the North.
“Increased smoke is also damaging air quality, limiting travel, and impacting subsistence activities for Alaska Native communities,” said Rogers, who co-leads Woodwell’s Permafrost Pathways project to accelerate equitable strategies to address permafrost thaw. “We need to seriously consider adjusting fire management priorities to account for carbon, as well as human health and other values. Our Joint Fire Science Program project fills a major gap in understanding what carbon is at risk from increasing wildfires, and how different management strategies may impact carbon emissions over time amidst a warming climate."
Prioritizing carbon and its co-benefits
Understanding the potential risks and opportunities in the changing fire environment, Yukon Flats refuge manager Jimmy Fox wanted to see if something could be done about it.
Previously, fires in Yukon Flats were monitored but not suppressed unless they threatened people or property. But by working together with the Alaska Fire Service, Indigenous communities, and other local groups, Fox and others came up with a plan to test another approach: selectively suppressing fire in the most carbon-rich areas of the refuge. They chose 1.6 million acres to include in the pilot project, and agreed to focus on small fires earlier in the season. This strategy aims to suppress fires when they are most manageable, thereby conserving the state’s limited firefighting resources.
Randi Jandt of the Alaska Fire Science Consortium pointed out that firefighting agencies must prioritize life and property first, then firefighter safety. “Natural resource protection, including habitat, forest resources, and carbon come after those," she said, "and in a typical Alaska fire season, resources like smokejumpers, helicopters, and aircraft get tapped out quickly."
However, she added that by targeting small fires early in the season, when resources are still available, the pilot project “may actually save money and resources by preventing those fires from becoming large and perhaps threatening other protected values later in the busy part of the season.”
“We have been talking about this growing concern for years,” said Fox. “Rather than doing nothing, we’re experimenting together. We will learn as we go, and minimize risks to firefighters.”
Using remote sensing, AI, and simulations to support decision making
Many questions remain about the Yukon Flats pilot project. Will suppressing fires to avoid carbon emissions lead to larger fires in the future? As forests transform from evergreen to deciduous trees, how will fire behaviors change? Should forest managers replant burned areas with black spruce, or let them naturally change into deciduous forest? This is where scientists like Hayes, Hall, and Hansen can help.
The team will use remote sensing, artificial intelligence, and detailed simulations of Alaska’s national wildlife refuges to test how different management strategies impact carbon storage and fire risk over the next century. The models — adapted from the Western Fire & Forest Collaborative, of which Hansen is the director — will also compare results across various future climate scenarios.
“Computer simulations allow us to compare outcomes of many different management strategies over larger spatial scales and longer time periods than could be done in the real world. This can equip managers with information on many different approaches,” said Hansen.
Rogers’ team at Woodwell will study the carbon consequences and cost-effectiveness of the Yukon Flats pilot project, looking to whether and how the project could be scaled in the future.
The first step will be to learn from decision makers and on-the-ground professionals like Fox, to better understand what questions and concerns they have, and to co-produce a research agenda.
Ultimately, the researchers hope their maps and insights will help to clarify where and why interior Alaska’s carbon is most at risk of fire, what factors influence postfire carbon recovery, and which strategies can best protect boreal carbon over the coming century.
The lessons they learn will have implications far beyond Alaska, potentially influencing the management of Canada’s boreal forests and helping to inform US national climate mitigation strategy.
