Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Shrub growth decreases as winter temps warm up

21.05.2014

Many have assumed that warmer winters as a result of climate change would increase the growth of trees and shrubs because the growing season would be longer. But shrubs achieve less yearly growth when cold winter temperatures are interrupted by temperatures warm enough to trigger growth.

“When winter temperatures fluctuate between being cold and warm enough for growth, plants deplete their resources trying to photosynthesize and end the winter with fewer reserves than they initially had. In the summer they have to play catch up,” said Melanie Harsch, a University of Washington postdoctoral researcher in biology and applied mathematics. She is lead author of a paper on the subject recently published in PLOS One.


Photo by Janet Wilmshurst

Dracophyllum on Campbell Island, New Zealand.


Photo by David Hollander

Discs cut from just above the shrubs’ root collar were studied to determine growth.

The roots are especially sensitive to temperature fluctuations, Harsch said. Warming winters result in higher root respiration, which uses up carbon reserves as plants make and release oxygen, leading to less carbon available during the regular growing season.

Harsch and her colleagues studied two species of shrubs on Campbell Island, an uninhabited UNESCO World Heritage site in the southwest Pacific Ocean about 375 miles south of New Zealand’s mainland. They studied two large shrubs, Dracophyllum longifolium and Dracophyllum scoparium, which are evergreen broadleaf species that can grow up to about 15 feet tall and live up to 240 years.

Researchers found that while warmer, drier winters helped seedlings get established, it adversely affected growth of older plants.

“For growth to occur you need sufficient precipitation and temperature and nutrients. Growth should only happen during the summer on Campbell Island when temperatures are above 5 degrees Celsius,” Harsch said. Five degrees C is about 40 F. “On Campbell Island most winters are cool and below this 5 degrees Celsius, so the plants are not active. The plants we studied are evergreen and there is little snow cover, so they are sensitive to changes in temperature.”

In this study, researchers cut out discs, called “cookies,” from just above the shrubs’ root collar, and measured the width between each ring to determine growth. They found that plant growth decreased as winter temperatures went up.

“On Campbell Island the snow is ephemeral, so the plants usually are not covered,” Harsch said. “If we’re going to see an effect in changing winter conditions, we’re going to see it at Campbell Island decades before we see it at, say, Mt. Rainier, where there is a lot of snow and winters are colder.”

Harsch said plants in areas like Campbell Island may eventually adjust to warmer winters, but the transition period will be tough as temperatures bounce above and below what plants need to stay dormant, causing the plants to draw down their resources.

“It may eventually be warm enough in the winters so that plants can photosynthesize and grow year round, like they do in the tropics,” she said. “It’s this transition part that plants are not adapted for.”

Harsch plans to do a follow-up study that would measure the microbes and carbon reserves in the soil, and manipulate snow packs to see how it affects establishment and growth.

“How much of this can our tree species withstand?” Harsch said. “Will summer growth eventually compensate for these hard winters, or is this some sort of extra stressor on trees that will be one more nail in the coffin? If you think of all the different factors of increasing vulnerability in climate change, is this really significant? We just don’t know.”

Co-authors are Matt McGlone and Janet Wilmshurst at Landcare Research in New Zealand. Harsch started the work while pursuing her doctorate at Lincoln University in New Zealand and finished the analysis at the UW. The work was supported in part by the National Science Foundation.

# # #

For more information, contact Harsch at harsch.melanie@gmail.com or 253-365-1555.

NSF grant: DEB-1103734.

Doree Armstrong | Eurek Alert!
Further information:
http://www.washington.edu/news/2014/05/20/shrub-growth-decreases-as-winter-temperatures-fluctuate-up/

Further reports about: Heritage Ocean Pacific Zealand species temperature transition

More articles from Life Sciences:

nachricht Not of Divided Mind
19.01.2017 | Hertie-Institut für klinische Hirnforschung (HIH)

nachricht CRISPR meets single-cell sequencing in new screening method
19.01.2017 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>