Forests take years to recover from a drought, new study finds

Instead, his study shows that – assuming they survive their respective droughts – most trees take an average of between two and four years after a drought’s end to recover and resume normal growth rates.

The reduced capacity of forests to absorb carbon dioxide and store them will hasten climate change, this means a future worse than models had predicted in the past.

“Right now those models…are kind of underestimating the impacts of drought”, said George Koch, a professor at NAU’s Center for Ecosystem Science and Society and one of the co-authors of the study.

‘This really matters, ‘ continues Anderegg, ‘because in the future, droughts are expected to increase in frequency and severity due to climate change.

By making use of computer modeling, researchers have always considered that trees quickly recovered from droughts and other weather conditions. Given the slow recovery rate, it is safe to say that less Carbon dioxide will be absorbed and climate change is likely to speed up. These provided a history of wood growth along with the carbon absorption. However, according to the new study of effect of droughts on the world’s forests, that hypothesis was not true.

Scientists from the USDA-Forest Service, South Dakota State University, the Desert Research Institute and the University of Tasmania, Australia looked at climate-induced variations in global wildfire danger from 1979 to 2013. Based on their observations, which have been carried out on an worldwide database of 1,338 global sites and non-tropical forests within the Northern Hemisphere, legacy effects last for two to four years.

In most of the world’s forests, trees had years-long struggles to recover after droughts, they found. For that matter, researchers think many more studies should be conducted in this field to determine the best solution to prevent severe droughts and to help trees recover at a much faster rate.

It is not known how droughts may cause long-lasting harm, though it could be from loss of foliage and carbohydrate reserves that impair growth, according to the study. They added that drought affected areas will gather pests and diseases and it will damage the area’s water system. “The fact that temperatures are going up suggests quite strongly that the western regions of the U.S. are going to have more frequent and more severe droughts, substantially reducing forests’ ability to pull carbon from the atmosphere”. “It really seemed to make the drought lethal to vegetation where previous droughts with the same rainfall deficit weren’t”, Anderegg says.

The scientists estimated the delayed drought recovery could reduce carbon-storage capacity in semi-arid ecosystems alone by about 1.6 metric gigatons over a century, a phenomenon that is not factored into current climate models.

“Drought, especially the type that matters to forests, is about the balance between precipitation and evaporation, and evaporation is very strongly linked to temperature”, Anderegg said in the release. That’s not how the real world works.’.