Drought’s Impact on Forests Causes Trees to Store Less Greenhouse Gases

In order to reach such conclusions, the scientists looked at the impact drought has on forests in various places all over the world.

According to the article on the University of Utah’s official news website, William R.L. Anderegg is an assistant professor of biology in the university.

Scientists are anxious that the damages that are brought on the trees are generally related to their ability to store water, which means numerous trees in forests do not fully recover after a severe drought.

This learning would suggest that forests on Earth aren’t able to store as much carbon as climate models have stated in the past, said lead author Anderegg in the release.

It is generally believed – and certainly assumed by most climate models – that although forest growth around the world is understandably impacted by drought conditions, once a drought is over, a forest will quickly return to normal, healthy growth levels. He co-authored the study with colleagues at Princeton.

“It seems like trees are pretty sensitive to drought and they just take a while to recover”. 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.

New research shows droughts can reduce tree growth for up to four years. But in the majority of the world’s forests, trees struggled for years after experiencing drought. In dry ecosystems, drought effects lasted longer-and in general, growth was about 9 percent slower than predicted during the first year of recovery. Two of the trees most affected by drought were pines and aspens, two common species of trees in the great boreal forest that stretches across Canada, as well as the forest lands of northwestern U.S. “These are the species that take risks – they tend to keep using water at a high rate even as drought progresses”, Anderegg says. According to the researchers, the loss of plants and carbohydrate reserve during drought weakens growth the following years. Pests and diseases may accumulate in drought-stressed trees.

This really matters because in the future, droughts are expected to increase in frequency and severity due to climate change. “Drought, especially the type that matters to forests, is about the balance between precipitation and evaporation. And evaporation is very strongly linked to temperature”. The deficit in precipitation was comparable to earlier droughts, but the temperature was 3 to 6 degrees F hotter than the long-term average. In addition, cone-bearing trees and flowering trees belonging to the categories of gymnosperms and angiosperms require more time to recover from severe droughts, scientists have concluded.

The carbon storage capacity lost to drought conditions is anything but trivial, the researchers note; over the span of a century, carbon storage capacity in semi-arid ecosystems alone would be reduced by around 1.6 metric gigatons and amount equal to around a quarter of the entire U.S. emissions annually.

The study’s results suggest that current Earth system models should incorporate the impact of drought on forests in order to provide more accurate predictions of how drought will alter the global carbon cycle.