Forest regrowth efforts find nitrogen speeds tropical recovery

A University of Leeds-led study tracked 76 regrowing tropical-forest sites for up to 20 years and found nitrogen additions roughly doubled recovery rates during the first decade, while phosphorus alone did not produce the same response.

Researchers at the University of Leeds led a long-term experiment examining how soil nutrients affect tropical forest recovery. The project ran in Central America and tracked 76 regrowing plots for up to 20 years. Plots received nitrogen, phosphorus, both, or no additions to isolate nutrient effects. The paper was published January 13 in Nature Communications. Key findings: - The study tracked 76 regrowing tropical-forest sites in Central America for up to 20 years. - Experimental plots received nitrogen, phosphorus, both, or no nutrient additions to isolate effects. - Forests with adequate nitrogen rebounded about twice as fast during the first decade. - Phosphorus additions alone did not produce the same recovery response. - Authors cautioned against broad fertilizer use and discussed nature-based alternatives such as planting nitrogen-fixing legumes or restoring areas with existing nitrogen deposits. - The research team included collaborators from the University of Glasgow, Smithsonian Tropical Research Institute, Yale, Princeton, Cornell, National University of Singapore and the Cary Institute. Summary: The study indicates that targeted nitrogen availability can speed early recovery in regrowing tropical forests and highlights restoration approaches that work with soil biology to increase carbon sequestration. Researchers warned that broad fertilizer application could have undesirable effects and described nature-based alternatives. Further study and monitoring were presented as important for understanding how these findings apply in different sites and over longer time frames.