Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How much drought can a forest take?

20.01.2017

Aerial tree mortality surveys show patterns of tree death during extreme drought

Why do some trees die in a drought and others don't? And how can we predict where trees are most likely to die in future droughts?


These are dead trees in the Sierra National Forest in April 2016.

Credit: USFS Region 5


This is a GIF showing dead trees per square mile in California between 2009-2015.

Credit: Derek Young/UC Davis

Scientists from the University of California, Davis, and colleagues examined those questions in a study published in the journal Ecology Letters.

Using climate data and aerial tree mortality surveys conducted by the U.S. Forest Service during four years (2012-2015) of extreme drought in California, they found that when a drought hits the region, trees growing in areas that are already dry are most susceptible.

The research also showed that the effects of drought on forests can take years to surface, suggesting that such effects may linger even after the drought has ended.

SOUTHERN SIERRA NEVADA TREES ARE MOST VULNERABLE

The study said that trees in the driest and densest forests are the most at risk of dying in an extreme drought. In California, that makes crowded stands of trees in the Southern Sierra Nevada the most vulnerable in the state.

The concept is simple: Trees in dense forests are like multiple straws competing for the same glass of water. In wet climate conditions, that competition goes largely unnoticed. But when it's dry, few are able to quench their thirst, setting the stage for mass mortality.

'HOW MUCH DROUGHT A TREE CAN TAKE'

"Our analysis found out how much drought a tree can take," said UC Davis Ph.D. student Derek Young, who co-led the study with Jens Stevens, a UC Davis postdoctoral researcher during the study who is currently at UC Berkeley, and Mason Earles, a postdoctoral researcher at Yale University. "If forest managers want to get the biggest bang for their buck in reducing forest vulnerability to drought, this study suggests they should focus on the densest stands in the driest areas. And when we reestablish forests burned by severe wildfire in these areas, we should plant at lower densities from the beginning."

Tree mortality in the Sierra Nevada in 2015 was the worst in recorded history. The U.S. Forest Service aerial tree mortality surveys in 2015 estimated 29 million trees in California had died after four years of extreme drought.

Though the drought began in 2012, major effects on trees did not appear immediately. While some trees died every year, mortality spiked only in the fourth year of extreme drought.

TREE MORTALITY A DELAYED REACTION

In a blog post he wrote on the subject in May 2016, Young noted: "This observation highlights the fact that tree mortality can take several years to respond to drought. Such a delayed response is often observed in studies of drought stress, and the existence of this delayed response hints that we are likely to observe high mortality well into 2016 and potentially beyond, especially in Southern California."

Indeed, surveys conducted by the U.S. Forest Service in 2016 estimated an additional 62 million trees died that year.

###

Other study co-authors include UC Davis associate professor Andrew Latimer, and Jeffrey Moore, Adam Ellis and Amy Jirka with the USDA Forest Service.

Study authors were supported by a National Science Foundation Graduate Research Fellowship, EPA STAR Fellowship, and a USDA Hatch Project.

Media Contact

Kat Kerlin
kekerlin@ucdavis.edu
530-752-7704

 @ucdavisnews

http://www.ucdavis.edu 

Kat Kerlin | EurekAlert!

More articles from Agricultural and Forestry Science:

nachricht The inner struggle of the evening primrose: Chloroplasts are caught up in an evolutionary arms race
14.03.2019 | Max-Planck-Institut für Molekulare Pflanzenphysiologie

nachricht Cereals use chemical defenses in a multifunctional manner against different herbivores
06.12.2018 | Max-Planck-Institut für chemische Ökologie

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

Im Focus: Sensing shakes

A new way to sense earthquakes could help improve early warning systems

Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...

Im Focus: A thermo-sensor for magnetic bits

New concept for energy-efficient data processing technology

Scientists of the Department of Physics at the University of Hamburg, Germany, detected the magnetic states of atoms on a surface using only heat. The...

Im Focus: The moiré patterns of three layers change the electronic properties of graphene

Combining an atomically thin graphene and a boron nitride layer at a slightly rotated angle changes their electrical properties. Physicists at the University of Basel have now shown for the first time the combination with a third layer can result in new material properties also in a three-layer sandwich of carbon and boron nitride. This significantly increases the number of potential synthetic materials, report the researchers in the scientific journal Nano Letters.

Last year, researchers in the US caused a big stir when they showed that rotating two stacked graphene layers by a “magical” angle of 1.1 degrees turns...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Researchers measure near-perfect performance in low-cost semiconductors

18.03.2019 | Power and Electrical Engineering

Nanocrystal 'factory' could revolutionize quantum dot manufacturing

18.03.2019 | Materials Sciences

Long-distance quantum information exchange -- success at the nanoscale

18.03.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>