Over the past century, the growth of tropical trees has remained minimally affected by droughts. As a result, the rate of CO 2 sequestration in tropical wood has been fairly stable. These are the main findings of a global study, led by Wageningen University & Research and to which Utrecht geoscientist Tom Wils also contributed. "Tropical trees are still fairly resilient to drought," says Wils. "But that resilience response has its limits – trees can't just tolerate everything." The research has now been published in Science.
The researchers used the largest collection of tropical tree-ring data to date: more than 20,000 tree-ring series from nearly 500 locations in 36 countries. They calculated that, on average across the tropics, trees grew 2.5% less during drought years compared to years with normal or above-average precipitation. This growth dip largely disappeared in the year following the drought. However, the researchers also warn that drought effects are much stronger locally, will aggravate as climate change progresses and have likely caused elevated tree mortality.