- The study modeled how the mix of tree species growing in a tropical forest following a disturbance, such as clearcutting, can affect the forest's ability to sequester carbon. The team found that the presence of trees that fix nitrogen could double the amount of carbon a forest stores in its first 30 years of regrowth. At maturity, forests with nitrogen fixation took up 10% more carbon than forests without.
Sarah Batterman, a Research Fellow at Cary Institute of Ecosystem Studies and coauthor on the paper, explains, "We want to use this work to guide tropical reforestation to optimize carbon uptake and resiliency. This requires understanding what mix of trees is needed to maximize long-term carbon storage while withstanding future climatic conditions. Our findings suggest that nitrogen-fixing trees are a key ingredient in the reforestation recipe."
Nitrogen-fixing plants partner with soil microbes to turn atmospheric nitrogen gas into a form of nitrogen that is available to fuel plant growth. Through these interactions, nitrogen fixers are able to self-fertilize. This adaptation gives them an edge in recently cleared, early succession tropical soils that are nitrogen-poor. Fixers also help fertilize nearby plants when they shed their leaves and return nitrogen to the soil.