When it comes to sucking carbon dioxide out of the atmosphere, trees and forests are well-known champions. But when it comes to sequestering methane, their role is much more complicated. Forest ecosystems sometimes absorb methane, other times they emit it — creating a complex exchange of gases that scientists are only beginning to understand. Boreal forests across Canada, Alaska, Scandinavia, and Russia can sometimes be methane sinks, but they’re also set to become major emitters as climate change accelerates.

That’s the challenge the Boreal Biosequester project is tackling. By deploying newly developed methane detecting chambers at Howland Research Forest in Maine, Woodwell Climate Associate Scientist Dr. Jennifer Watts and Senior Research Scientist Kathleen Savage, along with collaborators from Arizona State University and University of Maine Orono plan to measure methane flows on a granular level to understand which bacteria consume it and how they function across the ecosystem.

Once they’ve mapped these methane-munching microbes—called methanotrophs—across varying tree species, temperatures, and seasonal shifts, the researchers want to publish their findings so governments, land trusts and foresters can enhance the activity and presence of these climate superstars, transforming ecosystems from methane sources into sinks.

Why methane matters

Methane has been overlooked in climate discussions, which largely focus on carbon dioxide, but it’s 87 times more powerful at trapping heat over a 20 year period. Atmospheric levels of methane are now 2.6 times higher than pre-industrial levels—the highest they’ve been in 800,000 years. Crucially, methane emissions from boreal forests are expected to rise or even double as temperatures rise.

Natural environments, such as wetlands and forests, account for a large portion of global methane emissions, which is why finding nature-based solutions to bring down emissions is such an important area of research. Boreal Biosequester’s approach offers the chance to turn natural sources into sinks, while also providing co-benefits such as enhanced biodiversity, wildlife habitats, flood reduction, erosion prevention, and improved air quality.

“If the methanotrophs are there, why not learn to work with them as effectively as possible?” says Watts. “If we were to work with human technology to reduce methane, you’d have to build something energy-intensive. This is a passive way to work with the forest sustainably. If we leave a forest to grow or regenerate, or if we afforest, we can both draw down CO2 and, we hope, consume methane.”

The genesis of the project 

Watts and Savage were initially looking at methane sources and sinks for the US National Science Foundation. At first, they focused on soils, which were at the time considered the primary drivers of whether forests were sources or sinks. Then a groundbreaking paper revealed trees’ crucial role in methane uptake. With microbial ecologist Dr. Hinsby Cadillo-Quiroz from Arizona State University, they decided to study methane fluxes around tree trunks and canopies as well as in the soil, and sought funding from CarbonFix to carry out this study.

“When we looked at the canopy level, we could see net consumption, but soil data were all over the place,” Watts explains. “The data showed something important happening between the soils and treetops.”

The world of methanotrophs on plant surfaces is largely uncharted. The team will isolate and study these bacteria in labs while measuring methane consumption across soils, trunks, and canopies through different seasons and climates.

“We’re really the explorers venturing into this new micro-universe,” says Watts. “We know there are microbes out there, we just need to get to know them.”

Only in the last 15 years could methane gas be measured accurately at this scale. The team is uniquely positioned at Howland Forest, which has rare historical methane flux data from eddy covariance towers (structures measuring the exchange of gases) dating to 2011, plus access to both pristine and harvested forest areas for direct comparison.

The Method

CarbonFix’s grant will be used for the first phase to map methanotroph behavior and measuring fluxes across forest layers across the course of a year. Once they’ve secured additional funding, the team will identify optimal conditions for methane consumption across different tree species and environments. Next, they’ll test hypotheses in greenhouse settings, demonstrating how specific tree species can convert methane-emitting wetlands into methane-consuming ecosystems.

Finally, they’ll share findings through reports and presentations targeting governments, land trusts, foresters, and carbon markets to implement these practices in forest management.

Potential impact 

For now, the team will focus on working out how methanotrophs function, and the conditions in which they thrive. 

“A tiny creature, like a methanotroph, can influence a tree in many ways: it can fix nitrogen, it can clean metabolites. But the true beauty of this partnership is that a single tree could host methanotrophs in many ways and a thousand trees can host methanotrophs in a million ways. We just need to figure out how to channel this partnership to remove many tons of methane molecules. Achieving that would be a major breakthrough to help gain time against climate change,” says Cadillo-Quiroz. 

The findings may extend beyond forests to landfills, agriculture, logging, or fire-damaged areas — countless applications where understanding and influencing methane fluxes through bacteria could prove transformative.

What’s more, if the team’s findings show how methanotrophs can be inoculated into new forests, they could become part of every new reforestation project. 

Reforestation is urgently needed: between 2001-2023, Canada, Alaska, and the Northern US lost over 70 million hectares of forest — three times the UK’s landmass — from fire and harvest. Most of these wet soil areas are net methane emitters. Reforesting and inoculating them with methanotrophs could create carbon and methane sequestration superheroes. The team estimates targeted afforestation could remove over 10 million metric tons of methane — reducing 30-40% of high-latitude methane budgets while simultaneously sequestering CO2.

But for now, there’s lots of work to be done. The team of four are rolling up their sleeves for fieldwork and lab analysis. 

“At minimum, it will be fascinating data filling knowledge gaps about methane uptake,” says Savage. “If we can remove methane short-term, we have leeway to address more challenging CO2 elements requiring extensive work.”

Watts adds: “Our group is always thinking about how what we do now will impact society later. I’m excited to develop methodologies that we can share worldwide, creating community transformation for people across the planet.”

Trees play a crucial role in mitigating the effects of climate change by absorbing climate-warming carbon dioxide from the atmosphere. As temperatures climb and human activities release more and more carbon, managing and protecting trees has become essential to curbing global warming.

In 2021, partners at Woodwell Climate Research Center, Local Governments for Sustainability (ICLEI), and the World Resources Institute (WRI) launched a tool providing communities with fine-scale information about their trees to better manage and protect them. 

The Land Emissions and Removals Navigator (LEARN) tool is an interactive map and data analysis system that contains remote sensing and forest inventory data on tree cover, land use change, disturbances, and carbon stocks. Users – mostly county and municipal planners – can generate a custom estimate of carbon emissions and removals from trees for any area in the contiguous United States. 

“That’s the idea with the LEARN tool – it makes these complicated datasets readily accessible,” Dr. Rich Birdsey, Senior Scientist at Woodwell Climate and collaborator on LEARN, says. 

Easily accessible tree cover data gives community members the opportunity to take action at the local level. For example, a city planner might use LEARN to see if trees are gaining or losing cover in their city. If trees are losing cover, they can work with their municipal departments to increase the urban canopy. 

In the last year, scientists added the ability to identify mature and old-growth (MOG) forests to the tool. MOG forests are the later stages of forest development, where trees are larger and store more carbon than younger forests. They are also more resilient and adaptive in the face of disturbances and play a role in maintaining biodiversity by providing habitat for wildlife. This makes them a high priority for protection. 

In addition, users can now view the protection status of an area. Ranging from low to high, they describe what activities – like logging and mining – are allowed in the area. Users can draw connections between activities and carbon estimates, and hopefully, change local land management practices to better protect their trees. 

LEARN’s protection statuses include: 

“The assessment is more relevant now because the Department of Agriculture has proposed a rule that would relax forest protections, particularly with respect to roadless areas,” Birdsey says. 

In June, U.S. Secretary of Agriculture Brook Rollins announced that the U.S. Department of Agriculture is rescinding the 2001 Roadless Rule. The rule protected 58 million acres of roadless land within the National Forest System from construction and commercial logging. With no protections for roadless areas, logging and commercial uses of land will be allowed.

“Because of the large area currently designated as roadless, and the significant area of mature and old-growth forests within these areas, this is of great concern to the conservation community,” Birdsey says. 

Birdsey hopes that the LEARN tool can mobilize community members and land managers to take action. Whether it be working with local governments to protect MOG forests or connecting neighboring counties to each other, communities can collaborate to tackle climate change on a local level. 

“Since federal policies are opening up more public land to logging, it is becoming more important than ever for local communities to weigh in on forest management plans,”Birdsey says. 

At Fort Stewart-Hunter Army Airfield in Georgia, dozens of people in uniform position themselves along the edge of a pine stand as multiple aircraft approach overhead and a helicopter starts dropping incendiary devices into the forest in front of them. This may sound like a military training exercise but it is not. It is the NASA FireSense campaign, co-led in partnership with the Department of Defense and the U.S. Forest Service, a carefully planned and coordinated set of scientific experiments being used to better understand wildfires.

As wildfires get more frequent, intense, and destructive due to human activity, scientists are coming up with new and creative ways to study them. This is what brought me to this collaborative project at Fort Stewart in March 2025 for a week of prescribed burns and intensive wildfire research.

I’m an ecologist at Woodwell Climate Research Center working to understand how climate change is altering wildfires in boreal forests and the Arctic. I improve ecosystem models— computer software programs that simulate how ecosystems work— to better predict wildfire under a changing climate. This requires a holistic understanding of wildfires: from the way plants grow and produce fuels, to the weather that leads to fires, to how fires spread and grow.  For me, getting out in the field is an important way to confirm that my computer simulations are behaving like real fires.

Wildfires can be a difficult and dangerous environment in which to do research. For this reason, wildfire research is sometimes done during prescribed fires. Prescribed or controlled burns are lit by trained professionals to reduce the buildup of natural fuels and to benefit plants and wildlife, especially in ecosystems that historically had regular wildfires. Fort Stewart has one of the largest prescribed fire programs in the United States, burning around 115 thousand acres every year. Burns are performed both to protect soldiers from wildfires that can easily start during military training exercises, as well as to manage the base’s pine forests for the recovery of several threatened and endangered species including the red-cockaded woodpecker and the smooth coneflower. This makes it a great location to do research. Unlike wildfires, controlled burns allow researchers to know exactly when and where a fire will occur, giving them time to plan safe research projects.

This most recent experimental burn campaign represents a new level of cooperative effort to study wildland fire at all stages. While the Environment and Natural Resources Division Forestry Branch at Fort Stewart conducted the prescribed burns, researchers from NASA and seven DoD Strategic Environmental Research and Development (SERDP) funded research projects deployed weather stations, fire sensors, cameras, and emberometers on the ground. NASA flew three aircraft overhead with advanced sensors aimed at the fire below and a radar truck monitored the smoke plume. Fuels were measured with LIDAR scanners before and after the fires to detect what burned. During the fire, fuel moisture was measured. The ability to study conditions before, during, and after a fire gives a more complete picture of fire behavior compared to a wildfire where researchers are often limited to data gathered after the threat of the fire has passed. 

Working together like this makes for more than just good science, it also builds community. Like all scientists, wildfire researchers tend to be specialized, with some studying fuels, while others study smoke, or the energy produced by the flames. Bringing these people together allows them to share ideas, discuss problems, and learn new experimental techniques. These connections and conversations are what spark new ideas and collaborations that push science forward.  For me this was a valuable opportunity to meet other researchers, discuss ideas, and to learn how to perform experiments safely in a fire, something that could help me improve my wildfire models in the future.

The FireSense campaign at Fort Stewart went off without a hitch. The data collected during the campaign will take many months to analyze, but the hope is that this campaign will act as a model for a new era of cooperative wildfire research. Planning for another campaign next year in Florida is already under way and in the meantime I’ve returned to my lab to refine my code and apply what I’ve learned in preparation for the next fire.

When I started at Woodwell Climate, I had very little personal or professional experience with boreal wildfire. I was a forest ecologist drawn to this space by the urgency of the climate crisis and the understanding that northern ecosystems are some of the most threatened and critical to protect from a global perspective. More severe and frequent wildfires from extreme warming are burning deeper into the soil, releasing ancient carbon and accelerating permafrost thaw. Still largely unaccounted for in global climate models, these carbon emissions from wildfire and wildfire-induced permafrost thaw could eat up as much as 10% of the remaining global carbon budget. More boreal wildfire means greater impacts of climate change, which means more boreal wildfire. But when I joined the boreal fire management team at Woodwell, the global picture was the extent of my perspective.

This past June, under a haze of wildfire smoke with visible fires burning across the landscape, Woodwell Climate’s fire management team made our way back to Fort Yukon, Alaska. Situated in Yukon Flats National Wildlife Refuge at the confluence of the Yukon and Porcupine Rivers, this region is home to Gwich’in Athabascan people who have been living and stewarding fire on these lands for millennia. Our time there was brief, but it was enough to leave us humbled by the reality that the heart of the wildfire story—both the impacts and the solutions—lie in communities like Fort Yukon. 

We listened to community members and elders tell stories about fire, water, plants, and animals, all of which centered around observations of profound change over the past generation. As we shared fire history maps at the Gwichyaa Zhee Giwch’in tribal government office, we were gently reminded that their knowledge of changing wildfire patterns long preceded scientists like us bringing western data to their village. We learned that fire’s impact on critical ecosystems also affects culture, economic stability, subsistence, and traditional ways of life. Increasing smoke exposure threatens the health of community members, particularly elders, and makes the subsistence lifestyle harder and more dangerous. A spin on the phrase “wildland urban interface,” Woodwell’s Senior Arctic Lead Edward Alexander coined the phrase “wildland cultural interface,” which brilliantly captures the reality that these fire-prone landscapes, culture, and community are intertwined in tangible and emotional ways for the Gwich’in people.

“There’s too much fire now” was a common phrase we heard from people in Fort Yukon. Jimmy Fox, the former Yukon Flats National Wildlife Refuge (YFNWR) manager had been hearing this from community members for a long time, along with deep concerns about the loss of “yedoma” permafrost, a type of vulnerable permafrost with high ice and carbon content widespread throughout the Yukon Flats. With the idea originating from a sharing circle with Gwich’in Council International, in 2023 Jimmy enacted a pilot project to enhance the fire suppression policy of 1.6 million acres of yedoma land on the Yukon Flats to explicitly protect carbon and climate, the first of its kind in fire management policy. He was motivated by both the massive amount of carbon at risk of being emitted by wildfire and the increasing threats to this “wildland cultural interface” for communities on the Yukon Flats. 

Ever since I met Jimmy, I have been impressed by his determination to use his agency to enact powerful climate solutions. Jimmy was also inspired by a presentation from my postdoctoral predecessor, Dr. Carly Phillips, who spoke to the fire management community about her research showing that fire suppression could be a cost-efficient way to keep these massive, ancient stores of carbon in the ground. Our current research is now focused on expanding this analysis to explicitly quantify the carbon that would be saved by targeted, early-action fire suppression strategies on yedoma permafrost landscapes. This pilot project continues to show the fire management community that boreal fire suppression, if done with intention and proper input from local communities, can be a climate solution that meets the urgency of this moment.

“Suppression” can be a contentious word in fire management spaces. Over-suppression has led to fuel build up and increased flammability in the lower 48. But these northern boreal forests in Alaska and Canada are different. These forests do not have the same history of over-suppression, and current research suggests that the impacts of climate change are the overwhelming driver of increased fire frequency and severity. That said, fire is still a natural and important process for boreal forests. The goal with using fire suppression as a climate solution is never to eliminate fire from the landscape, but rather bring fires back to historical or pre-climate change levels. And perhaps most importantly, suppression is only one piece of the solution. The ultimate vision is for a diverse set of fire management strategies, with a particular focus on the revitalization of Indigenous fire stewardship and cultural burning, to cultivate a healthier relationship between fire and the landscape.

The boreal wildfire problem is dire from the global to local level. But as I have participated in socializing this work to scientists, managers, and community leaders over the past year, from Fort Yukon, Alaska to Capitol Hill, I see growing enthusiasm for solutions that is not as widely publicized as the crisis itself. I see a vision of Woodwell Climate contributing to a transformation in boreal fire management that has already begun in Indigenous communities, one that integrates Indigenous knowledge and community-centered values with rigorous science, and ends with real reductions in global carbon emissions. Let’s begin.

Last month in Dakar, Senegal, Woodwell Climate Associate Scientist Glenn Bush and Forests & Climate Change Coordinator Joseph Zambo facilitated a high-level workshop with the Democratic Republic of Congo’s Director of Climate Change, Aimé Mbuyi, lead scientist on the country’s Nationally Determined Contributions (NDC) reporting process, Prof. Onesphore Mutshaili, and project consultant Melaine Kermarc. The goal of the workshop was to begin generating a clear set of priorities for the next 5 years for stepping up the ambition of the country’s NDCs, and to discuss strategies for monitoring and reporting on emissions.

Under the Paris Agreement, each country is required to submit to the UN Framework Convention on Climate Change a detailed description of their emissions reduction commitments and then regular reports on progress. Currently, DRC has pledged to reduce emissions by 21% by 2030, focusing on reform in their energy, agriculture, forestry, and other land use sectors. While NDCs are intended to represent a country’s highest possible ambition, DRC is looking to step up further. Officials are at work developing a plan to reach net-zero emissions, which would place the country among the leaders of climate policy in Africa.

In order to do this, DRC needs a reliable framework for measuring and monitoring emissions, so that progress can be accurately reported on. At the workshop, Bush, Mbuyi, Zambo, Kermarc  and Mutshaili discussed ways to strengthen the NDC reporting process. Among the top needs identified was stronger institutional scientific capacity, increased coordination and data sharing, and more funding and awareness of the process at local and provincial levels.

“High quality data is essential to building a high integrity NDC,” says Bush. “Improving the scope and quality of data available to monitor carbon will not only help the country meet the highest tier of reporting standards, but also access performance-based payment mechanisms to help finance the transition to a low emissions economy.” 

Through their conversations about challenges and opportunities, the group identified three areas for intervention that will help the country navigate towards a stronger emissions reduction plan. These recommendations were outlined in a report on the workshop proceedings.

  1. Improved governance and policy management: Establishing a National Climate Change Council to better integrate climate policy into national development plans.
  2. Science-backed carbon accounting and budgeting: Developing credible data standards for measuring emissions and ecosystem services to support transparent and effective reporting on climate performance. 
  3. Cross-sectoral integration: Promoting emissions reductions across all sectors through collaborative partnerships, particularly in the field of climate-smart agriculture and carbon payment mechanisms. 

Mr Aimé Mbuyi, Head of the Climate Change Division (CCD) at the DRC’s Ministry of the Environment and Sustainable Development, declared that “these recommendations reflect an important set of practical steps to move from aspiration to operational reality in order to increase the financing and impact to conserve our forests and stimulate sustainable development in the DRC”.

Woodwell Climate Research Center has been a long time partner of the Ministry of Environment and Sustainable Development. The Center is assisting the ministry in laying the technical foundations to support the NDC improvement process and helping build in-country scientific capacity to make a net-zero emissions plan a reality. This and other partnerships will be essential in transitioning the DRC to a low-carbon economy.

“We appreciated the long-standing trust that has developed over years of formal and informal collaboration on climate policy,” said Mbuyi. “The scientific partnership with Woodwell is invaluable to us at CCD, providing actionable information that has proven essential to advancing the climate mitigation and adaptation agenda.”

I’m a field research scientist. What does this mean? I enjoy being outside, in forests and wetlands, studying the environment up close and personal. One of my favorite places to work and explore over the course of my career has been Howland Research Forest in central Maine. 

Dominated by red spruce, eastern hemlock, and red maple, this mature northern forest feels old. There is a 400 year old yellow birch that was already a mature tree during the American revolution. The ground is soft— spongy with a lot of “holes” where past trees have fallen and roots decomposed. My feet often plunge into these holes, which can sometimes be filled with water.

The Howland Forest Research station was established in 1986 by the University of Maine in partnership with a packaging and paper company, International Paper. My first trip to Howland Forest was in 1998 and at the time the research center was just a collection of trailers housing equipment. I had never seen so much mouse poop in a building. 

Howland was one of the first sites ever dedicated to measuring the net exchange of carbon between a forest and the atmosphere. Its support comes from the Ameriflux Network, a grass roots, science driven network of research stations spread across North and South America that monitors the flow of carbon and water across ecosystems. In these early years, Howland forest also served as a training site for testing out NASA’s remote sensing capabilities. At one time, Howland Research Forest was the most photographed site on earth from space. Soon the well used trailers were replaced with multiple buildings to accommodate the ever expanding research. The mice were evicted. 

Howland forest was selectively harvested over 100 years ago, evidenced by cut stumps, but the forest has remained intact, growing under natural conditions since then. Most trees range between 100-120 years old. In 2007, International Paper was scheduled to harvest these mature trees. Recognising the value of maintaining a continuous long-term record of observations, scientists from Woodwell Climate Research Center, The University of Maine (UMaine Orono), and the U.S. Forest Service (USFS) partnered with the Northeast Wilderness Trust (NEWT) to purchase the forest. The Howland Research forest, now owned by NEWT, was protected in a forever wild state. This science and conservation partnership saved an invaluable mature natural forest and research site. As scientists continued to collect data over the next decades, we would learn just how important this partnership was to our understanding of mature forests.

Long-term measurements of carbon exchange between the forest and the atmosphere are being taken from the top of a tower, as part of the Department of Energy (DOE) supported Ameriflux Network, and paired with measurements on the ground. It’s the measurements on the ground where I come in. Myself and collaborators at UMaine Orono, USFS and a host of other scientists and students over the decades have measured carbon exchange from soils, tracked changes in temperature and moisture, and taken tree inventories. 

Mature forests contain large stores of carbon in their tree stems, foliage, roots, and within the soils, accumulated over decades of growth and decomposition. Allowing mature forests to continue to grow, untouched, is beneficial to maintaining carbon stores along with the natural biodiversity and water cycling, often collectively called “ecosystem services”.  

Over the last 25 years, Howland Research Forest has seen the warmest, driest, and wettest years. Observations show an increasing trend in the net uptake of atmospheric carbon (as carbon dioxide) into this mature forest, meaning that Howland forest is continuing to take up and store more carbon each passing year.

If the forest had been harvested in 2007, observations spanning that shorter time frame would have indicated a decreasing trend in net net carbon uptake, meaning that Howland Forest was taking up less carbon each passing year.  

Although Howland Forest continues to take up carbon, the overall number of live trees has been declining (17% decline since 2001 in live trees, particularly red spruce and northern white cedar) and  the number of dead trees has nearly doubled since 2001. Theoretically, fewer live trees would indicate less carbon uptake, but that is not happening. The mature, large diameter trees continue to grow; although there may be fewer in number, they continue to take up significant amounts of carbon.

Tree species can differ in how they respond to environmental changes as well as how carbon is allocated within the tree and across a mature forest ecosystem. Teasing out these complex, multi-scaled, multispecies responses requires long term studies. However,  given the challenges to acquiring and sustaining funding for long-term studies, it’s unusual to have this type of paired dataset like we have at the Howland Research forest. This would not have been possible without the forward-looking vision of scientists and NEWT, and the consistent support from the Ameriflux Network.   

Thanks to its preserved, forever-wild status, a new generation of scientists has the opportunity to continue this work, building on our understanding of the mechanisms driving climate resilience in this mature northern forest.  

The partnership between science and conservation is a victory for both. Results from the Howland Research Forest demonstrate the need to continue supporting long-term studies to fully understand how natural, mature forests respond to a changing climate. Conservation organizations and land trusts are preserving and restoring critical habitats across the U.S. and the globe. This is an opportunity to build alliances between science and conservation, to inform how natural ecosystems function and the impact of restoration efforts on the ecosystem services that we all benefit from, while preserving natural spaces for future generations. 

The last decade has shattered global temperature records, with all 10 of the planet’s warmest years occurring since 2015. Under the Paris Climate Agreement, countries across the world are working to limit global warming to 1.5 degrees Celsius by decreasing their heat-trapping greenhouse gas emissions. But researchers say more action is needed to protect us from the worst impacts of climate change. 

“We’re beyond the point where emission cuts alone are going to keep us within a safe climate range. We need to remove carbon from the atmosphere,” Dr. Jonathan Sanderman, carbon program director and senior scientist at Woodwell Climate Research Center, says. “And there’s really two ways of doing that: tech-based solutions, like direct air capture or other engineering-based solutions, or we could try to reverse the last several 100 years of degrading nature and pull more carbon back into the biosphere.”

While both solutions are likely needed, Sanderman and others at Woodwell Climate are focused on using the power of natural environments, such as forests, wetlands, agricultural land, and rangelands, to reduce carbon in the atmosphere. These methods, called nature-based climate solutions, help combat climate change in three major ways: decreasing greenhouse gas emissions from deforestation, capturing and storing carbon from the atmosphere, and building ecosystems more resilient to climate hazards such as flooding and wildfires, according to the International Union for Conservation of Nature (IUCN). 

Natural climate solutions could contribute more than 30% of the cost-effective climate solutions needed globally in the next few decades. They could also save countries hardest hit by climate change $393 billion in 2050 and reduce climate hazards by 26%. 

Storing carbon on land

Sanderman researches one of Earth’s largest carbon pools: the soil. Plants release carbon they’ve absorbed from the atmosphere back into the ground when they die, which stores a total of about 2,500 gigatons of carbon globally. 

“Soils hold four times as much as trees do — about three times as much as the atmosphere,” Sanderman says.

Good land management can stabilize the amount of carbon in soil, but soils across the world have degraded substantially due to cultivation and overgrazing around the turn of the century. 

Storing carbon in the ground not only reduces the level of this greenhouse gas in the atmosphere, but carbon is the backbone of soil organic matter, which is a key regulator of soil health and crop yield consistency. It helps reduce erosion, keep soil structure in place and retain water. Carbon is often used as an indication of soil quality, with healthy soils usually containing about 2% organic carbon. Yet, precisely determining how much carbon is stored in soils worldwide — and which land management techniques lead to the most efficient carbon storage — is tricky. 

Rangelands as a nature-based climate solution

Sanderman is working with Dr. Jennifer Watts, the Arctic program director and an associate scientist at Woodwell Climate, to understand how much carbon dioxide U.S. rangelands are helping capture. These lands have big potential for sinking carbon: Rangelands make up about 31% of land area across the U.S. and about 54% across the world. Using both field data and satellite data, Sanderman and Watts are creating models of overall rangeland health in the U.S. Using this information, they can then quantify how much carbon is gained or lost over time under different scenarios.

“We are hoping, with our integrated system, to be able to provide the ability to scan all landscapes to determine their carbon status, and then go back in time and look at the trajectories of change,” Watts explains. “And provide that information directly to the land managers so they can make really informed decisions on where they should invest conservation work. At the same time, it’s great for us, because as an output, we get to quantify how much carbon is being gained versus lost in certain places and what the climate benefits are.”

Capturing Methane

While carbon dioxide is one of the most abundant and long-lasting greenhouse gases, methane is far more efficient at trapping heat in the atmosphere. Per molecule, it’s about 80 times more harmful in the atmosphere than carbon dioxide, though it lasts an average of only a decade in the air, whereas carbon dioxide can persist for centuries. Nevertheless, reducing methane emissions by 45% by 2030 could help us reach our goal of limiting global warming to 1.5°C, per the United Nations. 

Cutting anthropogenic methane emissions should be prioritized, but using nature-based solutions to increase uptake can also help bring down methane concentrations in the atmosphere. Although forests and soils play a smaller role in methane cycling, “When you start thinking about how much they can do over large areas, the numbers really get big,” Watts says. “And then it makes a huge difference.”

In northern forests across the U.S., Woodwell Climate researchers have set up methane monitoring systems, including specialized towers that measure the exchange of greenhouse gases, energy, and water between the ecosystem and the atmosphere. The team also analyzes soil samples from the forest to see exactly where methane-consuming and methane-producing microbes are thriving. 

The team has discovered a unique feature of the Howland Research Forest in Maine: It is an overall methane sink — though exactly why remains unknown. But by understanding more about how and under which conditions these methane-consuming microbes live, forest managers can change their strategies to harness the creatures’ natural power to reduce the effects of climate change. 

To combat the climate crisis, we must do “a lot of things simultaneously,” Watts says, including using good land management practices to capture and store greenhouse gases.

“Working with nature has a lot of advantages, because you’re optimizing the health of ecosystems, at the same time providing ecosystem services, not just for climate but also for local communities,” Watts says. “If we identify how to do this effectively, we’re really unleashing the power of something that’s already there, and then trying to work with it instead of against it.”

Associate Scientist, Dr. Brendan Rogers has walked in many forests, but primary forests, he says, “just feel different.” 

Rogers’ work often takes him to the cool, dark understories of black spruce and pine boreal forests, where he’s learned the subtle markers of a truly old, healthy, stable forest ecosystem.

“Generally cooler, often wetter, the trees are bigger but sparser and more likely to be conifers than shrubs or deciduous broadleaf trees,” says Rogers. “The ground is squishy to walk on, from the build-up of peat-like soils, mosses, and lichens.”

Primary forests are also a critical piece in the climate puzzle. They represent centuries of sequestered carbon, and every year they remain standing these forests continue to pull carbon from the atmosphere and lock it away in their trees and soils. They are also the subject of intense debates in forest management circles because, according to Rogers, despite knowing intuitively when you are standing in a primary forest, quantitatively identifying one is a tricky task. 

That fact hasn’t deterred Rogers and his collaborator Dr. Brendan Mackey at Griffith University, from their work to identify and map metrics indicative of primary forests. In a joint project launched in 2018, Rogers and Mackey created an index of one such metric— forest stability. 

Measuring forest stability

Forest stability is a measure of a forest’s resistance to disturbances, both manmade and natural. A stable forest has a high level of ecosystem integrity—a holistic term referring to the combination of ecosystem structure, function, species composition, and adaptive capacity. Stability reflects the ability of a forest to maintain all of those elements in the face of disturbance.

To quantify stability, Rogers and Mackey isolated two metrics that correlate heavily with integrity in forests— “greenness” and water stress. Greenness, also known as the fraction of photosynthetically active radiation (fPAR), indicates the amount of thriving, photosynthesizing plants. Water stress is an index of anomalies in vegetation moisture, indicating an area is dryer than usual. Both of these metrics can be remotely derived from satellites and, when combined with additional data, form an index of overall stability level. 

This index was first tested by a postdoctoral scientist at Woodwell Climate, Dr. Tatiana Shestakova, who pulled data from NASA’s MODIS satellite sensor to map stability in sample regions in the Kayapo Indigenous Territory in the Brazilian Amazon and southern Taiga region of Siberia. After testing the model, Rogers, Mackey, and Shestakova expanded it to map stability across the entirety of Ontario, Quebec, boreal Siberia, and the Amazon rainforest. 

The studies used a method called a time series analysis, which compares satellite data stretching back to 2002 to determine whether a forest had experienced a large-scale disturbance, reducing vegetation greenness and increasing water stress and thus lowering overall stability. These insights were only possible due to the long, consistent dataset produced by MODIS.

“It can be a little bit dicey to assess stability on shorter time scales,” says Rogers. “Because when you work with remote sensing data, forests can fluctuate year to year and sometimes you can’t completely eliminate things like cloud contamination or other errors from the data, so a longer time series helps smooth the data and lets you see the true patterns.”

Prioritizing protection for primary forests

These maps of stability have a crucial role to play in informing forest management policy.

“We’re trying to analyze and spatially map the ecological condition of forests,” says Mackey. “Because this information is needed to help guide where investments for forest protection and restoration go and how they should be prioritized.”

For a long time, Mackey says, management conversations did not distinguish between types of forests, lumping monoculture tree plantations into the same category as ancient natural forests, despite the vast differences in their carbon storage, biodiversity, ecosystem benefits, and overall resistance against disturbances. 

“We weren’t seeing the forest for the wood,” Mackey jokes.

Quantifying a characteristic like stability makes it easier for managers to see the difference between the two, identify the forests best able to provide myriad ecological benefits, and ideally, prioritize those for protection.

Mackey uses the example of woodland caribou in Canada, which are considered a threatened species. These animals require large areas of intact primary forest to support successful populations. Overlaying forest stability on top of caribou habitat maps can help decisionmakers narrow in on the largest, highest-stability tracts of forest as top priority for conservation.

According to Rogers, a future goal would be to eventually link maps of forest stability with carbon estimates in order to create forest protection plans with climate mitigation in mind. Research in primary forests has shown they continue to sequester carbon year over year, even though tree growth has tapered off. With primary forests in many places under intense political and economic pressures, it will become even more important to demonstrate the many co-benefits of protecting the earth’s stable forests.

“There’s no forest anywhere that isn’t threatened,” says Mackey. “Development, infrastructure, roading, damming, logging, clearing for agriculture. It’s happening everywhere.” 

Stable forests are resilient forests

Tracking stability of forests also allows us to approach a much harder-to-define characteristic of primary forests—resilience.  

Stability and resilience go hand in hand, though they are not the same thing. While resilience speaks to an ecosystem’s adaptive capacity or its ability to recover to its original state after some disturbance, stability is a measure of resistance, which is why it correlates so highly to primary forests that haven’t experienced any recent large-scale disturbance.

“If the stability index is showing recovery, then there’s obviously some resilience happening, but beyond that, primary forests tend to be more resistant to certain disturbances,” says Mackey. “Sometimes resistance is better even than being resilient. You’re not destroyed in the first place.”

Highly stable forests do tend to have better adaptive capacities as well, which is why they are so critical to protect.

“By and large,” says Rogers, “forests are resilient.” The stable ones can handle disruptions, and if you leave them to recover they will do just that, as he and Mackey have seen in the data.

But resilience is not infinite. If you hit too hard too fast—overlapping disturbances on an already unstable forest—you can overwhelm its resilience. Fires, larger and more frequent as a result of climate change, have already begun to override boreal forests’ adaptation. And there are more changes coming as the planet continues heating up. 

For now, at least, Rogers says, “resilience is still largely what we see out there.”