Featured Research

from universities, journals, and other organizations

Unexpected Relationship Between Climate Warming And Advancing Treelines

Date:
August 14, 2009
Source:
Wiley-Blackwell
Summary:
A new study reveals that treelines are not responding to climate warming as expected. The research, the first global quantitative assessment of the relationship between climate warming and treeline advance, is published in Ecology Letters and tests the premise that treelines are globally advancing in response to climate warming since 1900.

New research reveals that treelines are not universally responding to climate warming by advancing, as expected.
Credit: iStockphoto/Alexander Potapov

A new study reveals that treelines are not responding to climate warming as expected. The research, the first global quantitative assessment of the relationship between climate warming and treeline advance, is published in Ecology Letters and tests the premise that treelines are globally advancing in response to climate warming since 1900.

Related Articles


Treelines are the elevation or latitudinal limits where trees are capable of growth or survival and are considered to be early indicators of climate warming because they are constrained primarily by cold temperatures. Summer temperature is widely considered to be the primary control of treeline formation and maintenance, whereas winter temperatures have previously been considered less critical because of the insulative effects of snow. This study reveals how winter warming has overturned this prevailing view.

"Average temperatures have risen over the last century, with a more pronounced and rapid change at high altitudes and latitudes", said Ms. Melanie Harsch from the Bio-Protection Research Centre in New Zealand. "Within these zones, treelines are thought to be more temperature sensitive and so the rise in summer temperatures should result in an advance of treeline position."

Harsch and her co-authors conducted a multivariate meta-analysis, using a global dataset of 166 treeline sites with temperature data taken from the closest climate station to each site. The team used this data to analyse treeline advance throughout the 20th century and consider the contributing factors to that advance.

The team found that only 87 of the 166 sites (52%) had advanced while simultaneously the mean annual local temperatures had increased at 111 of the 166 sites at an average rate of 0.013˚C a year (or 1˚C in 77 years). Of the remaining sites, 77 (47%) remained stable and only two (1%) had treelines that receded. Both of the receding sites showed evidence of disturbance, indicating that regardless of form, location or degree of temperature change experienced over the last century, treeline positions have either advanced or remained static.

"Surprisingly these results reveal that treelines are not universally responding to climate warming by advancing, as expected," said Harsch, "However they demonstrate the importance of temperature on treeline advance over other factors such as disturbance, latitude, scale, elevation and distance to the ocean; none of which demonstrated strong relationships with the probability of treeline advance."

Another surprising result of this study was the association with winter, rather than summer, warming. These results provide no evidence of the prevailing view that high altitude and latitude treelines are controlled only by summer temperatures. Instead they show that treelines are more likely to advance at sites that had warmed during the winter months. It is known, at least in northern latitudes that climate-associated changes in winter conditions are on average more extreme than changes in summer conditions.

"These results show that treelines are responding to warming, but are not consistent in that only half of the sites showed signs of advance despite most sites experiencing warming. Several studies on plant species' responses to climate warming have shown mixed results and this study provides a possible explanation – both winter and summer conditions control treeline position," concluded Harsch. "Our expectations of response depend upon which factors are limiting the current treeline distribution. Where summer temperature is the primary limiting factor we can expect to continue seeing advance, but at other sites treeline advance is unlikely to occur until other limiting factors are first lessened."


Story Source:

The above story is based on materials provided by Wiley-Blackwell. Note: Materials may be edited for content and length.


Journal Reference:

  1. Harsch M, Hulme P, McGlone M, Duncan R. Are Treelines Advancing? A global meta-analysis of treeline response to climate warming. Ecology Letters, 2009; DOI: 10.1111/j.1461-0248.2009.01355.x

Cite This Page:

Wiley-Blackwell. "Unexpected Relationship Between Climate Warming And Advancing Treelines." ScienceDaily. ScienceDaily, 14 August 2009. <www.sciencedaily.com/releases/2009/08/090812202047.htm>.
Wiley-Blackwell. (2009, August 14). Unexpected Relationship Between Climate Warming And Advancing Treelines. ScienceDaily. Retrieved December 19, 2014 from www.sciencedaily.com/releases/2009/08/090812202047.htm
Wiley-Blackwell. "Unexpected Relationship Between Climate Warming And Advancing Treelines." ScienceDaily. www.sciencedaily.com/releases/2009/08/090812202047.htm (accessed December 19, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Friday, December 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Lava on Track to Hit Hawaii Market

Raw: Lava on Track to Hit Hawaii Market

AP (Dec. 19, 2014) Lava from an active volcano on Hawaii's Big Island slowed slightly but stayed on track to hit a shopping center in the small town of Pahoa. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. Video provided by Newsy
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Arctic Warming Twice As Fast As Rest Of Planet

Arctic Warming Twice As Fast As Rest Of Planet

Newsy (Dec. 18, 2014) The Arctic is warming twice as fast as the rest of the planet, thanks in part to something called feedback. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins