Tropical forests play a major role in slowing climate change because they absorb carbon dioxide (CO₂) from the air and store it in wood, leaves, and soil. A new study published in Nature Communications explains that nitrogen, an essential soil nutrient, can strongly speed up this carbon storage, especially in forests that are regrowing after deforestation. The findings help scientists better understand how tropical forests recover and how they can support climate solutions.
The researchers focused on “secondary” tropical forests. These are forests that grow back naturally after land has been cleared for farming or logging. Such forests are becoming more common across the tropics and have great potential to capture carbon quickly. However, their growth depends on nutrients in the soil. The study shows that in the early years of forest regrowth, nitrogen is often in short supply. When nitrogen is available, trees grow faster and store much more carbon.
By analyzing long-term forest data from tropical regions, the scientists found that young forests with higher nitrogen levels can absorb carbon at nearly twice the speed of forests with low nitrogen. As forests mature, this strong nitrogen limitation fades, and tree growth becomes less dependent on extra nutrients. This means nitrogen is most important during the first decades after forest disturbance, when carbon uptake can be especially rapid.
These results have important implications for climate action. Protecting and restoring tropical forests is already seen as a natural way to reduce the amount of CO₂ in the atmosphere. This study suggests that choosing the right locations for forest regeneration—such as areas with naturally higher nitrogen—or encouraging nitrogen-fixing tree species could greatly increase climate benefits. Nitrogen-fixing trees work with soil microbes to add nitrogen naturally, helping forests grow without heavy human inputs.
However, the researchers also warn against simple solutions like spreading chemical fertilizers over large forest areas. Excess nitrogen can pollute water, harm biodiversity, and release other greenhouse gases. Instead, the study supports careful, nature-based solutions that work with existing ecosystems.
Overall, this research shows that nitrogen plays a key role in how fast tropical forests can recover and store carbon. Understanding this process can help governments, conservation groups, and communities design smarter forest restoration projects that benefit both the climate and nature.
Editor of Daily 27.
Predoctoral researcher at the Department of Sociology in University of Barcelona.