Woodwell Senior Scientist Dr. Rich Birdsey has contributed his decades-long expertise in forestry and climate issues to two new U.S.-based forest policy initiatives. Working on both the state and federal level, Dr. Birdsey is helping to expand the influence of science in policy planning.

Federal forest policy

On July 20, Woodwell Climate submitted a response to the U.S. Forest Service’s request for public input into how they can adapt current policies and develop new ones to support the conservation of the country’s forests and increase their resilience in the face of climate change. The push for new rulemaking within the agency is a direct response to President Biden’s recent executive order: Strengthening the Nation’s Forests, Communities, and Local Economies.

Protecting forests is a crucial emissions mitigation strategy both within the US and globally. Forests, particularly mature and old-growth stands, contain centuries-worth of stored carbon and continue to sequester more each year. Loss of these precious forests releases stored carbon and reduces future carbon sequestration.

In the public comment, Dr. Birdsey, who led the drafting effort, emphasizes the importance of protecting mature and old-growth forests, stating, “When climate benefits are explicitly considered, the research points strongly to letting these forests grow—protecting and expanding the massive portion of sequestered carbon they represent. One of the largest threats facing mature and old-growth forests in the US is logging, which is a threat that humans can reduce instantly, simply by changing policy.”

Forest protection on the state level

Dr. Birdsey has also been named a scientific expert on a committee charged with helping draft Massachusetts’ forest policies. A new state initiative, called “Forests as Climate Solutions” looks to expand existing forest conservation activities and develop new forest management guidelines that can help Massachusetts meet its climate goal of achieving net-zero greenhouse gas emissions by 2050. The science committee will be responsible for providing input into the state’s proposals and assessing their effectiveness as climate solutions.

“Forests have to be at the forefront of our climate strategy,” said Massachusetts Climate Chief Melissa Hoffer. “Trees can sequester carbon for centuries—we have a responsibility to use the best science to ensure that their potential for carbon sequestration and storage is reflected in our approach.

Dr. Birdsey’s hope is that the policies developed by the new initiative will help Massachusetts take full advantage of its naturally carbon-rich forests.
“Massachusetts forests have some of the highest carbon stocks in the Eastern U.S., and I hope that policies enacted through this initiative will strengthen protection of older forests and large trees and foster management of younger forests to attain old-growth characteristics, while maintaining the current level of timber supplies,” says Dr. Birdsey.

Both policy initiatives present an important opportunity to set forest management on the right track towards achieving emissions reductions in years to come.

“Massachusetts’ forests have the potential to accumulate and store enough additional carbon to compensate for as much as 10% of the State’s current emissions from burning fossil fuels,” says Dr. Birdsey. “With climate-smart forests, Massachusetts can be a national climate leader.”

On April 20, 2023, the U.S. Department of the Interior (DOI) and Department of Agriculture (USDA) released a first-of-its-kind inventory of the country’s mature and old-growth forests. The assessment responded directly to a 2022 executive order aimed at fostering healthy forests.

The inventory highlights the importance of forest health in building resilience to future climate-related disturbances like drought or fire, but it omits mention of the service that all forests, but particularly mature and old growth forests, provide in directly mitigating the country’s carbon emissions—a service that Woodwell Climate’s scientists have worked to measure and monitor for over three decades.

The inventory is a critical starting point, from which agencies like the U.S. Forest Service and the Bureau of Land Management will begin to make decisions about how public forests are managed going forward. Not acknowledging the critical carbon storage contribution of mature and old-growth forests runs the risk of de-prioritizing protection for the country’s oldest, most carbon-rich, and hardest to replace ecosystems.

Why protect mature and old-growth forests?

In short: carbon. While all forests sequester carbon as they grow, older and larger trees represent an existing store of carbon in their biomass and soil. Research by Woodwell Climate scientists on carbon stocks in a sample of federally managed U.S. forests found that while larger trees in mature stands constitute a small fraction of all trees, they store between 41 and 84 percent of the total carbon stock of all trees.

An analysis of mature and old growth forests across the country found that approximately 76 percent (20.8 million hectares) of these forests are unprotected from logging. This represents an amount of carbon roughly equivalent to 1 quarter of the US’s annual fossil fuel emissions.

Although younger forests grow faster proportionally, they are not adding as much carbon in a single year as older forests with large trees. Additionally, mature forests continue to pack away carbon year over year in their soils, which is largely protected from effects of disturbance. Cutting down a mature forest creates a “carbon debt” that can take decades—centuries in some cases—to recoup, and in the meantime those mature trees are no longer sequestering carbon each year.

“Forests are like naturally occurring factories, delivering to the planet the unique service of carbon sequestration. Trees of all sizes, but particularly large old trees, are the equivalent of warehouses where the goods produced—tons of carbon—are stored over time,” says Woodwell Climate Carbon Program Director, Dr. Wayne Walker. “Like any warehouse where valuable goods are stored, these natural carbon reserves deserve all the protection we can provide. Their loss could effectively bankrupt our efforts to avoid the worst impacts of climate change.”

Defining mature and old-growth forest

Protecting mature forests requires them to be identified and mapped, which was part of the impetus behind the government’s forest inventory. But what actually is a mature forest?

Definitions of “mature” and “old-growth” differ, with no one universally accepted definition. Refining scientific understanding of what constitutes a mature forest has implications for either expanding or reducing the area of forest considered for protection.

In one study of U.S. forest carbon stocks, Woodwell Climate researchers and collaborators outlined a measure of forest maturity based on both the age that the tree canopy in a forest becomes 100 percent closed, called “Culmination of Net Primary Productivity,” and tree diameter size. Across 11 U.S. forests analyzed, the age at which a forest is considered mature ranged from 35 years in Appalachian forests to 75 in Arizona. “Old-growth” represents a smaller subset of mature forests having older and larger trees.

The new inventory from the DOI and USDA uses a slightly narrower definition of maturity, wherein the lower bound occurs when regeneration has begun underneath the canopy. This results in a slightly smaller estimation of the amount of mature and old-growth forests in the US—yet still approximately 63 percent of the total area of federally managed forests.

Other definitions can be based on models that take into account measurements of forest structure like canopy height, canopy cover, and biomass. Another study, co-authored by Woodwell Climate Assistant Scientist, Dr. Brendan Rogers, used these features to determine that federal lands contain the largest concentration of the country’s mature and old growth forests.

Differences in those definitions are important, because forest policy debates surrounding the responsible management of these forests depend on adequately identifying them, particularly mature forests, which are much more loosely defined than old-growth.

“I think the discussion is almost more about what to do with mature forests, as opposed to old-growth,” says Woodwell Climate senior scientist, Dr. Richard Birdsey, who worked in the U.S. Forest Service for four decades. “Mature forests are at a younger stage of growth—trees would be smaller, although they could still be substantial in size and very profitable to harvest. So the question here is whether to let those forests grow into old-growth characteristics, or to start harvesting them for wood products.”

What do we do with our mature forests?

When climate benefits are explicitly considered, the research points strongly to letting these forests grow—protecting and expanding the massive portion of sequestered carbon they represent.

According to Dr. Birdsey, the largest threat facing mature and old-growth forests in the U.S. is logging, which is a threat that humans can reduce instantly, simply by changing policy. A change that would make those forests more resilient to other threats in the long run.

“Others might argue that climate change or wildfire are more significant threats,” says Dr. Birdsey. “Older forests with larger trees are more resistant to those threats—but not more resistant to chainsaws. That’s a human decision.”

A recent paper in Nature Climate Change has laid out a “protect, manage, restore” framework for making decisions about what natural climate solutions to pursue, and the highest priority is always to protect carbon where it is already stored. U.S. policies have made some recent progress in this direction through the enforcement of the roadless rule on Alaska’s Tongass National Forest, prohibiting road-building and industrial logging on the 9 million acre temperate rainforest. But there is still further to go to capitalize on the carbon storage potential of the U.S.’s mature forests.

Federally managed forests contain more high-carbon trees than other lands, so the opportunity for increased carbon storage within them is greatest. Woodwell Climate Distinguished Visiting Scientist, Dr. William Moomaw, helped coin the term “proforestation” to refer to the strategy of letting forests continue to grow as a carbon solution. In order to achieve that, he says, mature forests have to be protected.

“The next steps should be to provide legal protection of as much of these high-carbon forests as possible,” says Dr. Moomaw. “These are public lands that should serve the public good, and reducing climate change is a public good that we should pursue as the highest priority.”

Switching light bulbs, recycling and composting, biking to school—to high school seniors Alice Fan, Amelia Kane, and Simone Colburn, these sorts of sustainability solutions being taught in their classes just didn’t feel like enough. 

“We were seeing a gap in climate education,” says Fan. “We would learn about the greenhouse gas effect, and about the polar bears, but the curriculum wouldn’t really touch on the human aspects of climate change, like environmental justice, redlining, and all the systemic issues that bring a different lens to climate change.”

Fan, Colburn, Kane, and some of their fellow students had come to understand the true scope of the issue through their individual interests and participation in activist and environmental groups outside of school. But the more involved they became, the wider the gap grew between them and their classmates. So they decided to take on the role of educators themselves, founding the Spring Forward Climate Education organization.

Spring Forward’s mission is to bring those larger conversations about climate justice into elementary and middle school classrooms, after-school programs, and summer camps. The organization’s high school members have developed lesson plans and activities that they lead for their younger peers. Mina Subramanian, Spring Forward’s Partnerships Coordinator, says climate education taught by students can be more impactful than receiving information from adults.

“I joined a climate organization before Spring Forward, but it was mostly adults. I felt like in that space, I didn’t have the voice that I wanted to,” Subramanian says. “But at Spring Forward, being youth led, it is such a different environment. We’re all on the same playing field and we all empower each other.”

Spring Forward has also begun branching out from classroom education, to develop additional materials that inform on broader climate topics. Collaborating with Woodwell, the team has created a policy brief around the issue of balancing solar panel installation with other land use considerations.

Solar panels require large clear tracts of land with good sun exposure. Some existing municipal development plans indicate their installation on land currently covered with forests or other vegetation. Forests are some of the best natural carbon sinks and sacrificing them in a rush to install renewable infrastructure is counterproductive. The Spring Forward team wanted to make the policy more accessible to the general public. 

“We need both solar and forests working together—not in competition—if we are going to be successful in addressing the climate crisis,” says Woodwell Carbon Program Director, Wayne Walker, who worked with the Spring Forward team on the brief. “Educating on these complex topics is so important, and the collaboration with Spring Forward offered me the unique opportunity not only to share some of my knowledge with the students, but also to play a small part in helping the students educate others.”

As the group continues to grow and evolve with new members and partnerships, they hope to temper the sting of a sometimes scary topic by showing both kids and adults that they have a voice they can use to make a difference. Talking about the problem helps everyone develop a path forward. 

“In our lessons we try to give information even if it’s scary, but then say ‘okay, well what can you do about it?’” says Colburn. “And one of our big beliefs is that if kids are getting weighed down by information, knowing that they can have power and that they can be influential is really helpful.”

A new study published in the peer-reviewed journal Forests and Global Change presents the nation’s first assessment of carbon stored in larger trees and mature forests on 11 national forests from the West Coast states to the Appalachian Mountains. This study is a companion to prior work to define, inventory and assess the nation’s older forests published in a special feature on “natural forests for a safe climate” in the same journal. Both studies are in response to President Biden’s Executive Order to inventory mature and old-growth forests for conservation purposes and the global concern about the unprecedented decline of older trees.

Scientists have long demonstrated the importance of larger trees and older forests, but when a tree is considered large or a forest mature has not been clearly defined and is relative to many factors. This study develops an approach to resolve this issue by connecting forest stand age and tree size using information in existing databases.  This paper also defines maturity by reference to age of peak carbon capture for forest types in different ecosystems. But the approach is readily applicable across forest types and can be used with other definitions of stand maturity.

Key findings include:

Researchers used thousands of forest plots obtained from the U.S. Forest Service “Forest Inventory and Analysis” (FIA) dataset to determine the amount of carbon absorbed from the atmosphere that accumulates and is stored in individual trees as they mature. As trees age, they absorb and store more carbon than smaller trees, making them uniquely important as nature-based climate solutions. Additionally, as the entire forest matures, it collectively accumulates massive amounts of carbon over centuries in vegetation and soils.  The study identified the forest age at which carbon accumulation is greatest, and used that as the threshold for defining a “mature” forest.  Scientists also determined the median diameter of trees at this threshold age and how much of the forest carbon of the larger trees in mature forests is unprotected from logging. The amount of carbon in unprotected larger trees in mature stands of the 11 forests studied, representing only 6% of federal forest land, is equivalent to one-quarter of annual emissions of carbon dioxide from fossil fuels in the U.S.  This is consistent with prior work.

According to lead researcher, Dr. Richard Birdsey of Woodwell Climate Research Center, “our study determined when an individual tree in a forest can be considered mature and when the forest itself is at an optimal rate of carbon capture and storage for conservation purposes. It is directly responsive to the president’s executive order.”

The Biden administration has set bold emissions reduction targets of 50-52% of 2005 levels and recently announced a “roadmap for nature-based solutions” as part of this effort. However, the roadmap neglects to connect the importance of protecting older forests to the climate targets. Federal agencies are proceeding with an inventory of mature and old-growth forests in response to the executive order, but policies regarding their management have not yet been established.  By protecting older forests and trees on federal lands from avoidable logging, the Biden administration can help close the gap on its emissions reduction goals.  The methodology in this paper provides a readily implementable path for critical policy solutions.

According to Dr. Dominick DellaSala, Chief Scientist at Wild Heritage, “there seems to be a big disconnect between what the White House is wanting and how federal agencies are responding to the president’s forest and climate directives. While the Forest Service recently withdrew a controversial timber sale in older forests on the Willamette National Forest in Oregon (“Flat Country Project”) because it was inconsistent with the president’s directives, dozens of timber sales in older forests remain on the chopping block.”

Dr. Carolyn Ramírez, Staff Scientist with the Forests Project at the Natural Resources Defense Council, pointed to the findings as supporting the push by over 100 conservation groups – the Climate Forests Campaign – for a national rulemaking to protect mature forests and big trees from logging for their superior climate and biodiversity benefits: “This work reinforces how essential mature forests on federal lands are to securing our climate future.  It’s now up to the agencies to protect these carbon storing champions from the chainsaw with formal safeguards.  Our approach shows that logging protections grounded in a straightforward, age-based cutoff—such as 80 years, as many are calling for—would protect significant amounts of carbon, accommodate forest growth differences, and be readily usable in the field.”

Haydee Hernandez-Yanez and Coleen smith measure carbon flux

Peterson Farm soil carbon ‘fieldwork’ for Opalite Media filming
June 2022

Nature-based climate solutions like reforestation, climate-smart agriculture, and wetland restoration harness natural processes to reduce greenhouse gas concentrations in the atmosphere and slow climate change. These approaches have substantial and growing support from bipartisan lawmakers, the private sector, and conservation-minded NGOs, but scientific tools to guide implementation and to accurately monitor outcomes are not adequately developed.

To confront that uncertainty and put nature-based climate solutions on a sound scientific footing, several dozen scientists and policy experts gathered in Washington D.C. in June of this year for a workshop sponsored by Indiana University, the U.S. Department of Energy, and the U.S. Carbon Cycle Science Program. The resulting white paper report reviews the current state of knowledge in this field, and describes the necessary research and technology investments to support effective mitigation policy.

According to the report’s lead author, Dr. Kim Novick from the Paul H. O’Neill School of Public and Environmental Affairs at Indiana University, “Nature-based climate solutions can play an important role in slowing the pace of climate change, but only if they are pursued alongside economy-wide decarbonization and guided by the best-available science.”

The white paper authors identify critical gaps in the science needed to support large-scale implementation of nature-based climate solutions and lay out a research agenda to fill these gaps. They also outline a set of principles that should guide future assessments of the effectiveness and viability of nature-based climate solutions. The result is a road map for producing information that will foster successful programs and policies—while avoiding energy wasted on those that do not.

Woodwell Senior Scientist, Dr. Jonathan Sanderman attended the gathering in June and contributed to the development of the paper.

“We’re at a unique moment in U.S. climate policy where the hard work of the research science community can be directly and immediately leveraged to help the U.S. fight climate change and become a world leader in implementing nature-based climate solutions.”

The report calls for a ~$1 billion (USD) coordinated investment in a national nature-based climate solution “Information Network” organized around coordinated ground-based experiments and monitoring that can inform rigorously benchmarked maps, model predictions, and protocol evaluations.

According to Dr. Benjamin Runkle, another report co-author and associate professor in the College of Engineering at the University of Arkansas: “Although the investment necessary to generate this information is not small, it is a fraction of the amount already allocated to implementation of nature-based solutions. Investing in sound science to predict, monitor, and verify the benefits of these strategies is fundamental to ensuring their success.”

In addition to their potential to stave off climate change, nature-based solutions also have a range of other benefits, including improving air and water quality,  promoting biodiversity, and providing economic opportunities. Many can also help communities adapt to a changing climate and improve resilience of agricultural and food systems.

“There is broad-scale agreement that many nature-based climate solutions benefit people and the environment through co-benefits,” said Dr. Emily Oldfield, a report co-author and agricultural soil carbon scientist with the Environmental Defense Fund. “We should push to incentivize those practices using a wide range of policy tools, while acknowledging there is no one-size-fits-all approach to ecosystem-based climate solutions.”

This year in climate, 2021

A look back at a turning point year for climate change

As another year passes with mounting emissions, we take stock of the big moments for climate change in 2021, from extreme weather events to steps forward on policy. Here’s is a look back at a potentially pivotal year for climate change:

Climate change is now front and center due to deadly weather

This year, the clear repercussions of climate change were impossible to ignore. Climate change worsens extreme weather, making Earth’s formerly reliable systems much more unpredictable. Widespread extreme weather events in 2021 had deadly consequences for the people caught in their paths.

In February, Texas experienced a cold snap that killed 210 people across the state and left millions without power for several days. The freeze was exacerbated by the stretching of the stratospheric polar vortex—a pool of cold air high over the poles that is usually hemmed in by strong westerly winds. When the polar vortex is disrupted from its typically circular shape, it can cause the jetstream to waver and plunge farther south, which can bring unusually cold temperatures farther south. Research has connected rapid warming and sea-ice loss in the Arctic north of western Russia with more frequent warping of the polar vortex, which could mean more of these extreme events in the northern hemisphere.

In the summer, temperatures swung in the extreme opposite direction as a heat wave settled over the Pacific Northwest, breaking records. Temperatures neared 120 degrees Fahrenheit, melting power cables, buckling brick roads, and causing sudden deaths to spike across the region. This phenomenon was also caused by a wavering jetstream that allowed an intense and persistent high-pressure system to trap the heat over the Northwest.

Hotter than average weather also led to record fires this year. In Siberia, the return of the fire season to the boreal forests brought with it blazes larger than concurrent fires in Greece, Turkey, Italy, the U.S. and Canada combined. Drought in Brazil, paired with rising deforestation rates, led to increased fires in the Amazon.

And finally, just this month the Midwestern U.S. was hit by a devastating string of tornadoes, more severe than usual for this time of year, marking the deadliest December tornado outbreak in history. Tornados are tricky to study, so an understanding of how their prevalence will fluctuate with climate change is not yet clear, but the conditions fostered by a warmer atmosphere are amenable for tornado formation.

Increased awareness has led to increased momentum

The undeniable severity of the climate impacts of 2021 has enforced the urgency of cutting emissions. This year, climate action began building the momentum it should have had two decades ago, with more than half of Americans concerned or alarmed about the issue, and governments and private sector organizations across the globe stepping up their commitments to tackling it.

In November, Glasgow, Scotland hosted the 26th annual COP—hailed by some as our “last, best, hope” for successful international cooperation on Climate Change. Although the larger negotiations were not as ambitious as necessary to confidently limit warming to 1.5 degrees Celsius, several steps still pushed the world forward. The conference opened with a pledge from 141 nations to end deforestation by 2030, accompanied by $19 million from governments and private sector groups—a large portion of which was dedicated to supporting Indigenous groups.

Earlier in the year, the U.S. Securities and Exchange Commission (SEC) made a request for public comments on a potential requirement for companies to disclose climate risk to their investors. With the impacts of climate change becoming more immediate, the demand for greater certainty around personal risk has grown. The SEC’s inclusion of climate risk in its regulations indicates a broader acknowledgement of the need to prepare for the changes to come. The new presidential administration in the U.S. also signaled its intent to address climate in its first 100 days, staffing up with science and policy advisers and calling an Earth Day summit with leaders from 40 nations.

What to watch for in 2022

So what can we expect as we enter another year?

As long as emissions continue at their current pace, so too will warming and its consequences. Storms, fires, and extreme temperature swings will become a more frequent fixture next year and into the future.

On the international stage, next year’s COP will be one to watch. Nations are expected to return with even more ambitious targets than agreed upon this year. The timelines for formal climate action will accelerate. In the U.S. we can expect to see a ruling from the SEC in early next year.

To match demand for more information on climate risk, Woodwell will be spearheading a collaborative climate risk coalition. The goal of the coalition is to produce an annual climate risk assessment for policymakers to aid future decision-making. Woodwell is also continuing its work conducting risk analyses for climate-related heat, flooding, and fire at the municipality level in several new cities. In 2022, Woodwell will be leading the push for more, transparent climate risk analyses.

2022 will also be a year of expanded research into the impacts of climate change, particularly the rapidly warming Arctic. Woodwell projects will expand our understanding of emissions from thawing permafrost and the behavior of Arctic fires, as well as impacts on extreme weather events. Researchers will also be working closely alongside Indigenous communities to both understand how climate change is impacting vulnerable communities, and support them to take part in climate solutions.