Forests recovering from Droughts show reduced Carbon Storage Capacity

As per the study, forests on Earth are storing less carbon than what experts were previously thinking.

We think of forests as handsome places, removers of carbon, and always there.

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.

Growth was about nine percent slower than expected in the first year, and five percent slower than expected in the second year. “Some forests could be in a race to recover before the next drought strikes”.

Taking into consideration the number of trees in the world, the decreased capacity will have a major impact on the presence of carbon dioxide in the atmosphere. He added that if forests are not properly storing carbon dioxide, this indicates that climate change would accelerate.

This study was co-authored by researchers from Princeton University, Northern Arizona University, University of Nevada-Reno, Pyrenean Institute Of Ecology, University of New Mexico, Arizona State University, U.S. Forest Service Rocky Mountain Research Station, NOAA Geophysical Fluid Dynamics Laboratory, and the Lamont-Doherty Earth Observatory of Columbia University.

The researchers write: “We found pervasive and substantial “legacy effects” of reduced growth and incomplete recovery for 1 to 4 years after severe drought”.

Using Dendrochronology, or tree-ring dating, we can get a snapshot of climate change.

They looked at the global Tree Ring Data Bank to determine the history of wood growth and track carbon uptake of the surrounding ecosystem.

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, as reported by the study. Pests and diseases may accumulate in drought-stressed trees.

It could also be that drought hinders trees’ ability to produce the tissues that transport water throughout the plant, reducing its capacity to take up and use water when it is available again. They found that all the methods gave similar results. “When drought conditions go away, the models assume a forest’s recovery is complete and close to immediate”, Anderegg said. The effects of droughts were most dramatic in dry ecosystems and among pine trees.

A vast swath of boreal forest supports many kinds of wildlife in Canada.

The fact that trees don’t immediately bounce back when precipitation returns has important implications for the models making predictions about the accumulation of manmade greenhouse gases in the atmosphere and the future of the world’s climate. There’s been documented increasing tree mortality rates. He says that because many wildfires are suppressed, the forests are denser than they should be. “Things like thinning out the density of trees would certainly increase resilience”.

‘In most of our current models of ecosystems and climate, drought effects on forests switch on and off like a light, ‘ says William Anderegg, assistant professor of Biology at the University of Utah, and lead author of the report.