Tropical forests can recover quickly on reclaimed agricultural lands

Although tropical forests worldwide have disappeared rapidly due to deforestation, they have the potential to regrow rather rapidly on abandoned lands, according to a new study, which finds that tropical forests and their soils are highly resilient to low-intensity land uses. The findings indicate that these secondary forests may play an increasingly important role in climate change mitigation and biodiversity and ecosystem restoration. Tropical forests in many parts of the world have been cleared to make way for other land-uses, including agriculture and livestock grazing. The gradual abandonment of these lands has led to a rapid increase in forest regrowth in these regions. However, a holistic understanding of how these forests recover and how long it takes for key forest functions to rebound has remained elusive. To better understand tropical forest regrowth in abandoned lands, Lourens Pooter and colleagues analyzed patterns of forest recovery in 77 secondary forest sites in the Americas and West Africa. Poorter et al. evaluated 12 forest attributes related to soil, plant functioning, ecosystem structure and biodiversity. They found that, while different attributes recover at different rates, tropical forests can recover quickly – attaining 78% of their old-growth values for these attributes in 20 years. According to the findings, near-total recovery of soil to old-growth values occurs in less than 10 years. Plant community and species diversity recover in fewer than 60 years. Recovery is slowest for biomass and species composition, taking roughly 120 years to reach 90% of old-growth values. Poorter et al. discuss how the findings could improve forest restoration monitoring and planning.