Tropical forests play an important role in regulating the global climate by absorbing and storing large amounts of carbon dioxide from the atmosphere. Due to the rise in deforestation, the speed at which these forests recover varies. Recent research conducted by the University of Leeds shows that one of the most important factors influencing forest regrowth is the availability of soil nitrogen. 

Nitrogen is essential for plant growth because it is one of the main components of chlorophyll, proteins and even DNA. These elements allow trees to photosynthesize, grow leaves and build woody tissue.

Young trees grow rapidly and have a high demand for nitrogen. When nitrogen is limited in the soil, tree growth slows down and forest recovery decreases.

The study study that even when other conditions are favorable, a lack of nitrogen can act as a bottleneck that restricts regrowth.

To understand how nutrients affect forest recovery over time, scientists established the world’s largest and longest-running experiment on the subject.

They monitored 76 forest plots across Central America, which were each roughly the size of one-third of a football field, for periods of up to 20 years.

These plots had a wide diversity of forests, ranging from different ages to those recovering from logging or agricultural clearing.

Researchers also set variables for treatments on the plots, including nitrogen fertilizer, phosphorus fertilizer, a combination of both or no fertilizer at all.

Over time, they measured tree growth, tree mortality and changes in forest structure, which allowed them to track long-term recovery patterns.

The results between forests with sufficient nitrogen and those without were striking.

Forests that had access to adequate nitrogen recovered about twice as fast during the first decade of regrowth.

Trees in these areas grew more quickly and had more biomass than the ones that did not have enough nitrogen, which recovered more slowly and captured significantly less carbon from the atmosphere.

These findings imply that nitrogen availability strongly influences how effective young tropical forests are. To counter this issue, farmers today use induced artificial nitrogen to expedite regrowth.

Despite the positive effects, researchers strongly discourage widespread use of nitrogen fertilizers in real-world forests. Applying fertilizer at large scales could lead to serious environmental concerns, including the release of nitrous oxide, a greenhouse gas far more potent than carbon dioxide.

Fertilizer runoff could also damage ecosystems and water quality. As a result, fertilization is not considered a sustainable climate solution.

The researchers suggest a safer method like planting nitrogen-fixing tree species from the legume family or prioritizing reforestation in areas where nitrogen levels are already high due to natural conditions.

These findings can help shape future reforestation and climate policies by improving estimates of carbon absorption and smarter forest restoration efforts.

Ultimately, the study reveals that preventing deforestation remains a top priority and understanding soil nutrients is essential for maximizing the climate benefits of forest recovery.