Subscribe to our free daily newsletters
. Earth Science News .

Subscribe to our free daily newsletters

Tallest trees could die of thirst in rainforest droughts
by Staff Writers
Edinburgh, UK (SPX) Nov 30, 2015

A control plot in a study of trees in the Amazon rainforest, where scientists from the University of Edinburgh have found that the tallest trees are likely to die of thirst, rather than starvation, in a drought. Image courtesy Patrick Meir. For a larger version of this image please go here.

Droughts could kill off the tallest trees in tropical rainforests in coming decades, a study suggests. For the first time, scientists have identified the ecological trigger that brings about the death of tropical rainforest trees during prolonged water shortages. Reduced rainfall forecast in coming decades could cause the breakdown of the transport system in trees that takes water up from soil to the leaves, scientists say.

This is likely to add significantly to the amount of carbon dioxide in the atmosphere through decomposition of the dead trees. It could also mean rainforests in the future are populated by smaller trees, which store less carbon, the team says.

Until now, how trees die from drought was poorly understood. Previous research suggested that a severe lack of water might have prevented trees from making enough sugars to fuel their metabolism, causing them to starve and die.

Findings from the world's longest-running drought study in tropical rainforest show that it is breakages in the trees' water transport system that lead to their death - rather than starvation. The results suggest that the Amazon rainforest is not resistant to intense droughts, or to long-term drought.

Over a 13-year period, researchers carried out fieldwork to assess the impact of drought on trees in the Amazon. Using a large-scale drought experiment, they monitored growth, sugar levels and the performance of the water transport system in the trees.

The researchers found that the amount of sugars stored in trees experiencing drought for more than a decade was similar to those in trees which had normal amounts of water during the same period. Drought-affected trees were found to grow at a normal rate right up until they died, indicating that they had enough sugars to fuel their metabolism and that starvation was not the trigger for death.

The study, led by the University of Edinburgh, shows that during severe drought, air bubbles can enter the sap of trees and break columns of water inside the tissues that transport water and nutrients - known as xylem. The tallest trees are most vulnerable to this process which can then lead to death; smaller trees are more likely to survive, the team says.

The study, published in the journal Nature, was funded by the Natural Environment Research Council, the Brazilian National Research Council, the European Union and the Australian Research Council. The work was co-led with the Federal University of Para, Brazil, and was carried out in collaboration with the Australian National University, the Universities of Leeds and Oxford, and research centres in Spain and Brazil.

Dr Lucy Rowland, of the University of Edinburgh's School of GeoSciences, and first author of the study, said: "Tropical forests play a key role influencing global and regional climate, and understanding the way rainforest trees respond to long-term changes in their environment is essential for improving predictions of the impacts of climate change."

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only


Related Links
University of Edinburgh
Forestry News - Global and Local News, Science and Application

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Previous Report
Top civil servants probed over hardwood traffic in Gabon
Libreville (AFP) Nov 27, 2015
Security agents in Gabon are investigating several top civil servants, including an advisor to the president, for illegal trafficking in a precious hardwood, a source close to the government said Friday. Some of the officials have been taken into custody by the General Directorate for Research (DGR) agency in the past week, while others were questioned and later released, the source told AFP ... read more

Russia causing 'environmental disaster' in Ukraine

Fukushima protective sea wall cracking

Climate change and conflict, a perfect storm

Brazil mining giant rejects UN anger over 'toxic' flood

Plant defense as a biotech tool

Material universe yields surprising new particle

Inkjet hologram printing now possible

Chemical design made easier

Increased carbon dioxide enhances plankton growth

Senegalese villages swallowed by the sea

Fish use smart camouflage mechanism in open ocean waters

CO2 keeps even small fry invasive carp at bay

Adapting to -70 degrees in Siberia: A tale of Yakutian horses

Very large volcanic eruptions could lead to ice sheet instability

Sea level rise from Antarctic collapse may be slower than suggested

Sea ice loss associated with increased summer land use by polar bears

Red clover genome to help restore sustainable farming

Study suggests bees aren't the be all and end all for crop pollination

French chefs cook up a storm for climate

Climate change threatens Tunisia olive farming

Nicaragua volcano belches ash, causes fears of eruption

Great Barrier Reef protecting against landslides, tsunamis

Hurricane Sandra surges to Category 4 in Pacific

Flooding brings Qatar to near standstill

Mugabe 'overjoyed' to host rare VIP visitor in China's Xi

China's Xi heads to Zimbabwe ahead of Africa summit

'Lay down your weapons', pope tells warring sides in C Africa

Massive 'development corridors' in Africa could spell environmental disaster

China cloning pioneer offers vision of brave new world

Fossilized Homo erectus skull found in China

Clues emerge about the earliest known Americans

Human brains evolved to be more responsive to environmental influences

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement