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:
- The minimum age at which forests may be considered mature, according to peak carbon capture, ranged from 35 to 75 years among the regions and forest types studied.
- The carbon stored in all trees of the 11 forests totaled 561 million metric tons, of which 73% is in larger trees and 60% is in unprotected larger trees in mature stands.
- For 8 of the 11 forests that had carbon accumulation data, the annual rate was 4.7 million metric tons per year, of which about half is in unprotected larger trees in mature stands.
- Forest stands with the greatest carbon stored and highest annual carbon accumulation were mainly in the Pacific Northwest, and all but one of the national forests (Black Hills in South Dakota due to drought and insect related tree mortality) experienced an increase in above-ground carbon over recent years.
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.”
Peterson Farm soil carbon ‘fieldwork’ for Opalite Media filming
June 2022
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.