Nitrogen is key to faster regrowth in deforested areas, say researchers
Tropical forests can recover twice as quickly after deforestation if they have adequate soil nitrogen, according to new research published today.
A team of scientists led by the University of Leeds established the world’s largest and longest experiment to see how nutrients affect forest regrowth in areas cleared for activities such as logging and agriculture.
They identified 76 forest plots across Central America – each about one third of the size of a football pitch and of varying ages – and studied the growth and death of trees for up to two decades.
The plots were given experimental treatments of either nitrogen fertiliser, phosphorus fertiliser, nitrogen and phosphorus fertiliser together, or no fertiliser at all.
The team found that the levels of nutrients in the soil strongly influenced tropical forest regrowth, with trees recovering twice as fast in the first 10 years when they had access to sufficient nitrogen, compared with when they did not.
The results of the research, which also involved scientists from the University of Glasgow, the Smithsonian Tropical Research Institute, Yale University, Princeton University, Cornell University, the National University of Singapore, and the Cary Institute of Ecosystem Studies, are published today in the journal Nature Communications.
Lead author Wenguang Tang, who carried out the research while studying for his PHD at the University of Leeds, said: “Our study is exciting because it suggests there are ways we can boost the capture and storage of greenhouse gases through reforestation by managing the nutrients available to trees.”
The research team used nitrogen fertiliser for the purposes of the experiment but do not advocate for fertilising forests as that would have negative consequences, including emissions of the powerful greenhouse gas nitrous oxide.
Instead, they advocate that forest managers should plant trees from the legume (bean) family which naturally fertilise the forest with nitrogen, or plant trees in areas that already have sufficient nitrogen because of the effects of air pollution.
Tropical forests are seen as vital global carbon sinks which can mitigate against climate change by removing carbon from the atmosphere and storing it in trees, a process known as carbon sequestration.
The researchers believe that if their findings were extended to include young tropical forests globally, a lack of nitrogen could be preventing the annual sequestration of 0.69 billion tonnes of carbon dioxide, roughly equivalent to two years of carbon dioxide and other greenhouse gas emissions in the U.K.
The research is published just weeks after the close of COP 30 in Brazil where the Tropical Forest Forever Facility (TFFF) fund was announced to support tropical forest countries in protecting and restoring their forests.
Principal investigator Dr Sarah Batterman, an Associate Professor in Leeds’ School of Geography, said: “Our experimental findings have implications for how we understand and manage tropical forests for natural climate solutions.
“Avoiding deforestation of mature tropical forests should always be prioritised, but our findings about nutrient impacts on carbon sequestration is important as policymakers evaluate where and how to restore forests to maximise carbon sequestration.”
Ends
Further information
Tropical forest carbon sequestration is accelerated by nitrogen is published today in Nature Communication. The DOI number is 10.1038/s41467-025-66825-2
Photo captions:
[Photo of person in orange] A team member spreads fertilizer on a plot that was a recently abandoned pasture to test the effects of soil fertility on forest recovery. Credit: Sarah Batterman
[Photo of two people] Team members lay out plots in a recently abandoned pasture where the forest is allowed to naturally regenerate. About fifty percent of tropical forests are in recovery from deforestation or degradation. Credit: Sarah Batterman
[Landscape image] is the secondary forest landscape in Agua Salud, Panama. Forests in the research site experienced long-term disturbances, including clear-cutting and cattle ranching. Credit: Wenguang Tang
For media enquiries, please contact Kersti Mitchell via k.mitchell@leeds.ac.uk
The research was funded by the Heising-Simons Foundation, the Carbon Mitigation Initiative at Princeton University, the Leverhulme Trust, the United Kingdom Natural Environment Research Council Council (NE/M019497/1, NE/N012542/1), the British Council 275556724 with additional support from Stanley Motta, Frank and Kristin Levinson, the Hoch family, the U Trust, Andrew W. Mellon Foundation and Scholarly Studies Program of the Smithsonian Institution, Chinese Scholarship Council-University of Leeds joint scholarship and Priestley Centre for Climate Futures, and Singapore’s Ministry of Education (IG19_SG113).
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Journal
Nature Communications
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Tropical forest carbon sequestration is accelerated by nitrogen
Article Publication Date
13-Jan-2026
Recovering tropical forests grow back nearly twice as fast with nitrogen
Study recommends strategies to help young forests soak up carbon faster
image:
Recovering forest in Panama
Credit: Credit: Wenguang Tang
Young tropical forests play a crucial role in slowing climate change. Growing trees absorb carbon dioxide from the air, using photosynthesis to build it into their roots, trunks, and branches, where they can store carbon for decades or even centuries. But, according to a new study, this CO2 absorption may be slowed down by the lack of a crucial element that trees need to grow: nitrogen.
Published in Nature Communications and coauthored by Cary Institute of Ecosystem Studies ecologist Sarah Batterman, the study estimates that if recovering tropical forests had enough nitrogen in their soils, they might absorb up to an additional 820 million metric tons of carbon dioxide each year for a decade.
“Nitrogen is limiting how quickly young forests can regrow,” said Batterman, senior author on the paper. “When we added nitrogen to the soil, forests grew back almost twice as fast in the first 10 years. Faster growth rates mean faster absorption of carbon dioxide, which can help to give us a few more years to reduce our carbon emissions.”
Rather than fertilizing young forests, the scientists recommend planting nitrogen-fixing trees in regenerating forests and, when possible, prioritizing forest restoration on lands that receive nitrogen pollution from farms and factories.
A giant study
About 50% of tropical forests are recovering from disruptions such as logging, wildfire, and agriculture — all processes that can cause nitrogen to leak out of the soil. Phosphorus is also thought to be a limiting nutrient in tropical forests.
Scientists, led by Wenguang Tang at the University of Glasgow, wanted to test how adding nitrogen and phosphorus fertilizers would affect the growth rates (and therefore carbon absorption rates) of tree trunks and branches in recovering tropical forests. The experiment encompassed 76 hockey-rink-sized plots in Panama, each covering 1600 square meters. The plots ranged in maturity at the start of the experiment, including newly regenerating forests, middle-aged forests that had been regenerating for 10 and 30 years, and mature forests with limited human disturbance for hundreds of years. The plots received additional nitrogen, phosphorus, both, or none. Some of the sites have been monitored since 1997.
“Our work represents the world’s largest and longest nitrogen and phosphorus addition experiment of its kind,” said Tang. “Each of our 76 plots has been censused at least five times, and in each census, data were collected from more than 20,000 trees. Maintaining high-quality, consistent census data over such a long period and across so many individuals was extremely challenging.”
The nitrogen effect
The team found that adding nitrogen caused the forest to regrow a whopping 95% faster in recently abandoned agricultural fields, and 48% faster in forests that had been recovering for 10 years.
“It was pretty amazing to see,” said Batterman. “The plots with added nitrogen looked so much bigger than the ones where we didn’t add nitrogen — the trees were just huge. We were surprised how quickly the forest grew back and how strong the effect of nitrogen was.”
For the forests 30 years and older, adding nitrogen had no effect, likely because nitrogen had built up in the soil over time, thanks to nitrogen-fixing trees. These trees cooperate with bacteria to pull nitrogen gas out of the atmosphere, converting it into a form of nitrogen that plants can use.
A phosphorus puzzle
Contrary to scientific expectations, adding phosphorus to the soil made no difference to forest growth rates at any age — a striking result, said lead author Tang. “This result challenges the long-standing theory that tropical forest carbon sinks are fundamentally constrained by phosphorus availability.”
It is possible that phosphorus addition did result in changes to the trees’ roots or fruits, which were not measured in this study. Another explanation is that trees in these forests have evolved creative ways to overcome phosphorus limitations. The scientists hope to investigate this thread further, to better understand what strategies trees use to maintain high productivity despite low phosphorus in the soil.
“Future work should also examine how consistent these patterns are in other tropical forests, including in Africa and Asia,” said Tang. “However, we expect nitrogen limitation in young tropical forests may be quite common. It’s likely becoming increasingly important, too, as forest disturbances increase and carbon dioxide levels rise in the atmosphere.”
Putting the research into practice
If nitrogen limitation is indeed widespread, the team estimates it may prevent recovering tropical forests from absorbing an additional 470 to 840 million metric tons of carbon dioxide per year. That’s roughly equivalent to taking 142 million gasoline-powered cars off the road each year.
To achieve those gains, the team does not advocate for adding fertilizer to overcome nutrient limitations. Nitrogen fertilizer is expensive and energy intensive to produce; it can also pollute waterways and lead to emissions of nitrous oxide, a powerful greenhouse gas. Instead, the team recommends being more strategic about where to focus on forest regeneration and which tree species should be planted at these sites.
“Ideally, forest stewards could make sure that some of the trees in a regrowing forest are nitrogen-fixers,” said Batterman.
Another strategy recommended by the team is to prioritize reforestation in areas where there is high nitrogen pollution from agriculture, factories, and transportation. This way, the trees can clean up the nitrogen pollution before it clogs waterways or turns into greenhouse gases, and the forests will grow back faster.
“These practices could increase how quickly these recovering forests take in carbon dioxide,” said Batterman. “In the long-term, the forests are not going to sequester extra carbon, but in that first 10 years, they can do the job faster, and 10 years is what we really need right now. We need to make big changes to reduce our fossil fuel emissions, such as shifting to clean energy and swapping out our gas guzzlers for electric vehicles, and unfortunately, that switch is taking longer than we need it to. Reforestation is one tool that can buy us more time to decarbonize and delay the worst effects of climate change.”
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Authors
Wenguang Tang, University of Glasgow, University of Leeds
Jefferson S. Hall, Smithsonian Tropical Research Institute
Oliver L. Phillips, University of Leeds
Roel J. W. Brienen, University of Leeds
S. Joseph Wright, Smithsonian Tropical Research Institute
Michelle Y. Wong, Yale University, Cary Institute of Ecosystem Studies, Smithsonian Tropical Research Institute
Lars O. Hedin, Princeton University
Michiel van Breugel, National University of Singapore, Smithsonian Tropical Research Institute
Joseph B. Yavitt, Cornell University
Phillip M. Hannam, Cary Institute of Ecosystem Studies
Sarah A. Batterman, Cary Institute of Ecosystem Studies, University of Leeds, Smithsonian Tropical Research Institute (*corresponding author)
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This study is a contribution of the Agua Salud Project and the Gigante Fertilization Experiment. Research was funded by the Heising-Simons Foundation, the United Kingdom Natural Environment Research Council, the Andrew W. Mellon Foundation, and Agua Salud core donors, among other sources.
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Cary Institute of Ecosystem Studies is an independent nonprofit environmental research organization. Since 1983, our scientists have studied the complex interactions that shape the natural world and how climate change affects ecosystems. Our research supports effective resource management, evidence-based policy, and environmental literacy. Our staff are global leaders in the ecology of forests, freshwater, soils, disease, and cities.
Cary Institute scientist Dr. Sarah Batterman uses a map to locate a plot in the ten-year-old forest behind her. The research team established 76 of these plots, which were 0.16 hectares in size. Some were fertilized by nitrogen, some by phosphorus, some by nitrogen and phosphorus together, and some with no fertilizer. The team tracked the growth and death of trees within the plots to test the effect of nutrients on forest carbon accumulation.
Credit
Credit: Jefferson Hall
A team member spreads fertilizer on a recently abandoned pasture plot. White tubes mark locations in the plot so researchers can locate trees as they grow back. After four years, the trees in this plot were taller than the researchers, and the forest stored twice as much carbon when they had sufficient nitrogen compared to when they did not.
A root nodule on a legume tree where symbiotic bacteria fix nitrogen from the atmosphere into a form of nitrogen that the trees can use to grow. Legume trees are abundant in tropical forests and can be used in reforestation efforts to naturally enrich the soil with nitrogen that speeds up carbon sequestration and storage.
A tropical forest that is about thirty years old, following deforestation and agricultural use. At thirty years, the forests show no evidence of nutrient limitation on carbon accumulation. Orange paint on tree trunks allows researchers to find and measure the same trees every year to track their growth and carbon storage.
Credit
Credit: Sarah Batterman / Cary Institute of Ecosystem Studies
Journal
Nature Communications
Method of Research
Experimental study
Article Title
Tropical forest carbon sequestration accelerated by nitrogen
Article Publication Date
13-Jan-2026
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