Featured Research

from universities, journals, and other organizations

Loss of eastern hemlock will affect forest water use

Date:
May 9, 2013
Source:
USDA Forest Service ‑ Southern Research Station
Summary:
The loss of eastern hemlock from forests in the Southern Appalachian region of the United States could permanently change the area's hydrologic cycle, reports a new study.

The loss of eastern hemlock from forests in the Southern Appalachian region of the United States could permanently change the area's hydrologic cycle, reports a new study by U.S. Forest Service scientists at the Coweeta Hydrologic Laboratory (Coweeta) located in Otto, North Carolina, published online in the journal Ecological Applications and available now in preprint format.

"The hemlock woolly adelgid, an exotic invasive insect, has caused widespread hemlock mortality," says Steven Brantley, a post-doctoral researcher at Coweeta and lead author of the paper. "Hemlock decline is expected to have a major impact on forest processes, including transpiration."

Transpiration describes the loss of water from plant leaves or needles. Coweeta researchers estimated changes in transpiration at the forest-level since hemlock woolly adelgid infestation by monitoring tree water use and changes in forest composition from 2004 to 2011. The four studied stands were once dominated by eastern hemlock trees, and are located in the Coweeta watersheds.

Because of its dense evergreen foliage and dominance in riparian and cove habitats, eastern hemlock plays an important role in the area's water cycle, regulating stream flow year round. The loss of hemlock from southern Appalachian forests can be compared to the loss of American chestnut from eastern forests, which became functionally extinct after the introduction of an exotic fungus in the early 20th century. Changes in local forest hydrology from the loss of eastern hemlock will largely depend on which species replace it.

Rhododendron, a woody evergreen shrub common in southern Appalachian forests, is one of the species replacing eastern hemlock trees. Although rhododendron is evergreen, it has lower leaf area than hemlock, and thus transpiration in rhododendron-dominated forest stands is lower than in previously-healthy hemlock forests. Most of the other species replacing eastern hemlock trees are deciduous, such as sweet birch, which unlike the evergreen rhododendron and eastern hemlock, do not transpire during the winter. Sweet birch trees also have a much higher transpiration rate than eastern hemlock trees during the growing season.

"The cumulative effect of these species changes will probably mean permanent changes in seasonal transpiration patterns," says Brantley. "In the growing season, transpiration rates will likely rise, leading to lower stream flow in the summer. However, transpiration rates in the winter will be reduced, which could cause increased winter stream discharge." Whatever species eventually replace eastern hemlock, there will be important long-term implications for riparian habitats beyond stream discharge. Without the shade provided by eastern hemlock, stream temperatures could rise, threatening aquatic animals like eastern brook trout that require cold water for survival. The loss of eastern hemlock will not only affect the animal and plant communities in riparian habitats, but ecosystem function throughout these areas.

The study was conducted at the U.S. Forest Service Coweeta Hydrologic Laboratory, in the Nantahala Mountains of western North Carolina. Coweeta is one of the oldest continuous environmental studies in North America. Since 1934, precipitation, temperature, and stream flow have been continuously recorded at Coweeta, a U.S. Forest Service Southern Research Station facility.


Story Source:

The above story is based on materials provided by USDA Forest Service ‑ Southern Research Station. Note: Materials may be edited for content and length.


Journal Reference:

  1. Steven T. Brantley, Chelcy R. Ford, James M. Vose. Future species composition will affect forest water use after loss of eastern hemlock from southern Appalachian forests. Ecological Applications, 2013; 130228133738005 DOI: 10.1890/12-0616.1

Cite This Page:

USDA Forest Service ‑ Southern Research Station. "Loss of eastern hemlock will affect forest water use." ScienceDaily. ScienceDaily, 9 May 2013. <www.sciencedaily.com/releases/2013/05/130509123655.htm>.
USDA Forest Service ‑ Southern Research Station. (2013, May 9). Loss of eastern hemlock will affect forest water use. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2013/05/130509123655.htm
USDA Forest Service ‑ Southern Research Station. "Loss of eastern hemlock will affect forest water use." ScienceDaily. www.sciencedaily.com/releases/2013/05/130509123655.htm (accessed July 31, 2014).

Share This




More Earth & Climate News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Visitors Feel Part of the Pack at Wolf Preserve

Visitors Feel Part of the Pack at Wolf Preserve

AP (July 31, 2014) Seacrest Wolf Preserve on the northern Florida panhandle allows more than 10,000 visitors each year to get up close and personal with Arctic and British Columbian Wolves. (July 31) Video provided by AP
Powered by NewsLook.com
Florida Panther Rebound Upsets Ranchers

Florida Panther Rebound Upsets Ranchers

AP (July 31, 2014) With Florida's panther population rebounding, some ranchers complain the protected predators are once again killing their calves. (July 31) Video provided by AP
Powered by NewsLook.com
Big Waves In Arctic Ocean Threaten Polar Ice

Big Waves In Arctic Ocean Threaten Polar Ice

Newsy (July 30, 2014) Big waves in parts of the Arctic Ocean are unprecedented, mainly because they used to be covered in ice. Video provided by Newsy
Powered by NewsLook.com
Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
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:
from the past week

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