Restoring rainforests right: Good for climate and biodiversity

Both birds and the climate could benefit if rainforests cut down by loggers are properly restored, according to new research from the University of Leeds.

In fact, a properly rainforest can — within just 15 years — support as much bird diversity as virgin forest, according to David Edwards with the university’s faculty of biological sciences.

Because trees in tropical climates soak up large amounts of carbon dioxide, restoring logged forest through planting new trees could also be used in carbon trading, Edwards says. He’s calling for the inclusion of biodiversity-friendly strategies in carbon trading schemes to ensure that carbon off-setting projects support, rather than undermine, rainforest conservation.

Currently, large plantations of one type of tree, such as Eucalpytus, are popular as carbon off-setting or sequestration projects in the tropics because they also provide commercial benefits. However, they don’t support tropical biodiversity.

Edwards has found that managed restoration of logged forest — which can also be used for carbon off-setting — brings biodiversity virtually back to pre-logging levels within 15 years, much quicker than forest left to regenerate naturally.

“Our research shows that it is possible to have both carbon sequestration and biodiversity benefits within the same scheme,” he said. “Birds have proven to be a fairly reliable indicator of how other groups such as plants and insects respond to habitat management, so this suggests that other groups might also benefit.”

He continued, “This could act as a strong incentive to protect logged forests under threat of deforestation for oil palm and other such crops. Selectively logged rainforests are often vulnerable because they’re seen as degraded, but we’ve shown they can support similar levels of biodiversity to unlogged forests.”

In his study, Edwards compared biodiversity of birds in three adjoining areas of tropical forest in the north-east of Borneo. One is the oldest and largest area of rehabilitated forest in the tropics, logged around 20 years ago and with over 10,000 hectares actively rehabilitated for the past fifteen; another is a naturally regenerating area of forest, logged at the same time; and the third, a conservation area of unlogged forest.

His findings showed the number and range of species of birds in rehabilitated tropical forest recovered to levels very close to those found in unlogged forest after just 15 years. Forest that was left to regenerate naturally after selective logging showed less diversity.

“There are now suggestions that carbon crediting and ‘biodiversity banking’ should be combined, enabling extra credits for projects that offer a biodiversity benefit,” Edwards said. “We believe this should be introduced as soon as possible, to ensure maximum support for rehabilitation schemes in the tropical rainforest.”

Edwards’ research, funded by the Leverhulme Trust, is published in the journal Conservation Biology.