The green belt of tropical rainforests that covers equatorial regions of the Americas, Africa, Indonesia and Southeast Asia is turning brown. Since 1990, Indonesia has lost 50 percent of its original forest, the Amazon 30 percent and Central Africa 14 percent Fires, logging, hunting, road building and fragmentation have heavily damaged more than 30 percent of those that remain.
These forests provide many benefits: They store large amounts of carbon, are home to numerous wild species, provide food and fuel for local people, purify water supplies and improve air quality. Replenishing them is an urgent global imperative. A newly published study in the journal Science by European authors finds that there is room for an extra 3.4 million square miles (0.9 billion hectares) of canopy cover around the world, and that replenishing tree cover at this full potential would contribute significantly to reducing the risk of harmful climate change.
But there aren’t enough resources to restore all tropical forests that have been lost or damaged. And restoration can conflict with other activities, such as farming and forestry. As a tropical forest ecologist, I am interested in developing better tools for assessing where these efforts will be most cost-effective and beneficial.
Over the past four years, tropical forestry professor Pedro Brancalion and I have led a team of researchers from an international network in evaluating the benefits and feasibility of restoration across tropical rainforests around the world. Our newly published findings identify restoration hotspots – areas where restoring tropical forests would be most beneficial and least costly and risky. They cover over 385,000 square miles (100 million hectares), an area as large as Spain and Sweden combined.
The five countries with the largest areas of restoration hotpots are Brazil, Indonesia, India, Madagascar and Colombia. Six countries in Africa – Rwanda, Uganda, Burundi, Togo, South Sudan and Madagascar – hold rainforest areas where restoration is expected to yield the highest benefits with the highest feasibility. We hope our results can help governments, conservation groups and international funders target areas where there is high potential for success.
These losses have dire consequences for global biodiversity, climate change and forest-dependent peoples.
As my work has shown, tropical forests can recover after they have been cleared or damaged. Although these second-growth forests will never perfectly replace the older forests that have been lost, planting carefully selected trees and assisting natural recovery processes can restore many of their former properties and functions.
But restoration is not uniformly feasible or desirable, and the benefits that forests provide are not evenly distributed. To make informed choices about restoration efforts and investments, organizations need more detailed spatial information. Existing global maps of restoration opportunities are based on actual versus potential levels of tree canopy cover. We wanted to go beyond this measurement to identify where the greatest potential payoffs and challenges lay.
We also assessed three aspects of feasibility: cost, investment risk and the likelihood of restored forests surviving into the future.
We studied these variables across all lowland tropical moist forests worldwide, dividing them into 1-kilometer square blocks that had lost more than 10 percent of their tree canopy cover in 2016. Each of the seven factors we studied had equal weight in our calculation of total restoration opportunity scores.
Read the full story about forest conservation and climate change.