Trees can supply a host of benefits for animals and people, but some trees planted in the tropics may be doing more harm than good. New research finds that 92 percent of new tree plantations planted in the tropics between 2000 and 2012 were in biodiversity hotspots, and 14 percent were in arid biomes, where trees are unlikely to thrive and likely to damage existing ecosystems. Tree plantations had also encroached into 9 percent of accessible protected areas in the humid tropics, such as national parks. Especially because 45 percent of reforestation commitments to the Bonn Challenge come in the form of tree plantations, it's critical to understand their full impact.
Trees store carbon, filter the air, create habitat, and supply a host of other benefits for animals and people. Planting the right trees, in the right places, in consultation with local communities, can support goals like addressing climate change and improving lives. However, new research led by Matthew Fagan, assistant professor of geography and environmental systems at UMBC, finds that some trees planted in the tropics may be doing more harm than good.
The study, published in Nature Sustainability, examined the increase in tree cover across the global tropics between 2000 and 2012. Fagan and colleagues found that, surprisingly, tree cover gains during that period were equally attributable to natural forest regrowth and the creation of tree plantations. The most common tree plantation species were rubber, eucalyptus, and oil palm.
Tree plantations are not always harmful to the environment, and even much-maligned oil palm can be farmed sustainably, Fagan explains. However, the study found that 92 percent of new tree plantations were in biodiversity hotspots, threatening a range of plant and animal species. Also, 14 percent of plantations were in arid biomes, where trees are unlikely to thrive and likely to damage existing ecosystems. And tree plantations had encroached into 9 percent of accessible protected areas in the humid tropics, such as national parks.
