US forests are locking in major carbon emissions
Nature plays big role in shaping regional carbon storage, study shows
COLUMBUS, Ohio – U.S. forests have stored more carbon in the past two decades than at any time in the last century, an increase attributable to a mix of natural factors and human activity, finds a new study.
To unravel the cause behind this spike, researchers used nationwide forest data to examine how six environmental factors may have contributed to the increase in carbon sequestered by forests. They found that natural forces such as increasing temperatures, shifting precipitation, and carbon fertilization are among the largest contributors to carbon gains, but human drivers, like letting forests get older and planting trees, are also becoming bigger factors.
Since most decarbonization efforts focus on curbing active emissions, this new analysis aims to help researchers better separate what portion of carbon held by forests is related to human action and which portion isn’t, said Brent Sohngen, co-author of the study and a professor of environmental and resource economics at The Ohio State University.
“Identifying and separating these influences hasn’t really been done before,” said Sohngen. “But with this data, the U.S. can be much more explicit about its carbon accounting, and that ability will provide a lot more information and long-term benefits for people who manage their forests and try to create carbon sinks.”
The study was published recently (Jan. 20, 2026) in the Proceedings of the National Academy of Sciences.
Forests act as vital tools to slow warming of the planet, as the more carbon that trees sequester, the less there is in the atmosphere. Large areas such as the Amazon Rainforest and the Congo Basin are known as “passive” carbon sinks because they absorb more carbon than they release without the need for human intervention.
In temperate regions, forests like Ohio’s Wayne National Forest are more likely to become carbon sources because they require extensive active inputs, such as tree-planting or other forest management activities to remain a strong sink, said Sohngen.
“The forests that we aren’t managing are doing exactly what we want them to do, which is to be ecosystem buffers,” he said. “That’s a good thing, but as we hit global carbon thresholds, the strength and size of that sink is slowing down in all these forests.”
The study looked at six drivers – temperature, precipitation, carbon dioxide, management, age composition and area – and the team was surprised by exactly how much natural factors influenced the total amount of carbon stored by U.S. forests. For instance, changes in temperature and precipitation from 2005 to 2022 led to an increase of 66 million metric tons of carbon sequestration per year.
During the same period, human intervention had both negative and positive effects, as human-caused deforestation reduced stored forest carbon by about 31 million tons per year, while activities like tree-planting and reforestation added about 23 million tons per year. Yet it was forest age — mostly structural changes in the peak growth stages of local trees — that helped lock in the most carbon, by 89 million metric tons per year.
Overall, these results suggest that while climate policies are doing their part to mitigate current climate challenges, scientists should also recognize the extent to which natural processes continue to shape our world.
This work also highlights the vast difference in the amount of carbon forests can absorb naturally versus when they are actively managed. If used in tandem with other environmental analyses, these findings may help other countries better plan how to utilize their national forest inventories to meet future net-zero requirements, said Sohngen.
Going forward, researchers may seek to localize their observations further, as having more detailed state or county carbon forestry data could help inform conservationists and wildlife managers on how to optimize the well-being of their land on a local rather than regional level.
“We have to think about how we start to address the impacts of climate change in parts of the country where there’s a slowdown of forest growth, and figure out how to adapt a region’s forests to the best climate future possible,” said Sohngen.
Co-authors include Eric C. Davis from the United States Department of Agriculture-Economic Research Service, and David J. Lewis from Oregon State University. The research was supported by the U.S. Department of Agriculture, Economic Research Service.
#
Contact: Brent Sohngen, Sohngen.1@osu.edu
Written by: Tatyana Woodall, Woodall.52@osu.edu
Journal
Proceedings of the National Academy of Sciences
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
How much of the forest sink is passive? Case of the United States
Article Publication Date
20-Jan-2026
Choosing the right biochar can lock toxic cadmium in soil, study finds
image:
Selective application of biochars to realize biochar–microbe synergistic immobilization of soil cadmium
view moreCredit: Yanqing Xiong, Rongrong Lin, Yafeng Wang, Kai Liu, Jiawen Guo, Min Wu, Quan Chen, Patryk Oleszczuk & Bo Pan
Cadmium contamination in agricultural soils is a growing global concern, threatening food safety, crop productivity, and human health. New research shows that not all biochars work the same way and that choosing the right type of biochar can make the difference between trapping toxic metals in soil or unintentionally making them more mobile.
In a study published online on January 15, 2026, researchers report that biochar produced at high temperatures can work together with soil microbes to effectively immobilize cadmium, one of the most hazardous heavy metals found in farmland worldwide. The findings offer new guidance for using biochar as a precise and reliable tool for soil remediation.
Biochar is a carbon rich material made by heating organic waste in low oxygen conditions. It has been widely promoted as a sustainable solution for improving soil quality and reducing pollution. However, past studies have produced mixed results, leaving farmers and land managers uncertain about how to use it effectively.
“Our results show that biochar is not a one size fits all solution,” said corresponding author Quan Chen of Kunming University of Science and Technology. “Its performance depends strongly on how it is made and how it interacts with soil microorganisms.”
The research team produced biochar from kitchen waste at three different temperatures: 300, 500, and 700 degrees Celsius. They then tested these biochars in pot experiments using cadmium contaminated agricultural soil and Chinese cabbage as a test crop. Some treatments also included the addition of a common, non pathogenic bacterium, Escherichia coli, to better understand microbial effects.
The results revealed a striking contrast. Low temperature biochar improved soil fertility and microbial activity but had little ability to lock cadmium in place. When combined with microbes, it even increased cadmium bioavailability and plant uptake, raising potential food safety risks.
In contrast, biochar produced at 700 degrees Celsius significantly reduced the most mobile and bioavailable forms of cadmium in soil. When paired with microbes, it showed a strong synergistic effect, further stabilizing cadmium and limiting its movement from roots to edible plant tissues.
“High temperature biochar creates a porous, alkaline microenvironment that favors beneficial microorganisms while restricting cadmium mobility,” Chen explained. “This synergy between biochar and microbes is the key to long term stabilization.”
The study found that high temperature biochar enriched specific microbial groups such as Bacillus, Rhodococcus, and Mucor, which are known to interact with metals through adsorption, biofilm formation, and mineral precipitation. These microbes formed a more tightly connected community that helped keep cadmium bound in less harmful forms.
Importantly, the research highlights that inappropriate biochar selection could backfire. Applying low temperature biochar in cadmium contaminated soils may increase metal uptake by crops, even if plant growth appears healthy.
“This work provides a clear warning,” said Chen. “If biochar is applied without considering its properties and microbial interactions, it may fail to reduce pollution or even worsen the problem.”
By demonstrating how biochar production temperature governs both chemical and biological processes in soil, the study offers a new theoretical basis for the selective and precise use of biochar in heavy metal remediation.
The findings support the development of tailored biochar strategies that maximize environmental benefits while minimizing risks. As countries seek sustainable solutions to soil contamination and food safety challenges, understanding these biochar microbe interactions could help turn organic waste into a powerful tool for cleaner and safer agriculture.
===
Journal reference: Xiong Y, Lin R, Wang Y, Liu K, Guo J, et al. 2026. Selective application of biochars to realize biochar–microbe synergistic immobilization of soil cadmium. Environmental and Biogeochemical Processes 2: e001 doi: 10.48130/ebp-0025-0019
https://www.maxapress.com/article/doi/10.48130/ebp-0025-0019
===
About the Journal:
Environmental and Biogeochemical Processes (e-ISSN 3070-1708) is a multidisciplinary platform for communicating advances in fundamental and applied research on the interactions and processes involving the cycling of elements and compounds between the biological, geological, and chemical components of the environment.
Follow us on Facebook, X, and Bluesky.
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Selective application of biochars to realize biochar–microbe synergistic immobilization of soil cadmium
Article Publication Date
15-Jan-2026
No comments:
Post a Comment