Featured Research

from universities, journals, and other organizations

Survival Of Quaking Aspen Groves A Complex Problem

Date:
August 8, 2001
Source:
Penn State
Summary:
Quaking aspen groves in the American West have been on the decline since the beginning of serious settlement and exploitation, but recent studies of California aspen by Penn State geographers suggest that the aspen decrease is more complicated than previously thought.

Madison, Wis. -- Quaking aspen groves in the American West have been on the decline since the beginning of serious settlement and exploitation, but recent studies of California aspen by Penn State geographers suggest that the aspen decrease is more complicated than previously thought.

"Since European settlement began in about 1850, about 60 to 90 percent of the aspen forests have disappeared, taken over by conifers such as pines, spruce and fir," says Dong Ko, a recent Penn State graduate with a master's degree in geography.

"In just the last 50 years, there has been a 30 percent decline," Ko told attendees at the 86th annual meeting of the Ecological Society of America today (Aug. 7) in Madison, Wis.

Quaking aspen, the most widely distributed tree in the northern hemisphere, is found from coast to coast in a band that includes northern California, the Rocky Mountains, Wisconsin, upstate New York and New England. Beside being noted for their shimmering leaves and the golden color they turn in the fall, aspen are unusual because they grow as clones, putting out vegetative shoots rather than forming seeds from which saplings sprout.

"Much research exists on aspen groves in the intermountain West and especially about their decline there," says Dr. Alan Taylor, professor of geography. "But there is no published information on aspen stands from California. Nothing was known about them."

Assumptions for the decline of the intermountain aspen stands include the suppression of frequent fires, increased livestock grazing, and increased and concentrated herds of native herbivores including deer and especially elk. The same environmental factors were believed to affect California stands as well.

Ko and Taylor studied 20 aspen groves on the California side of the Lake Tahoe Basin. The Penn State researchers identified the ages of the trees in the stands and the types of trees found. Surprisingly, they found only 15 percent or five stands that showed a shift in composition toward coniferous, shade-tolerant species. In the remainder of the groves studied, 12 had stable aspen populations with evidence of self replacement and 3 showed regeneration of both aspen and conifers.

The researchers warn that the history of the Lake Tahoe Basin is unique. Most of the forests were clear-cut in the 1870s to supply wood to the miners of the Comstock Lode. The Basin's aspen stands are mostly around 120 to 130 years old.

"If the young age of the stands is not a factor, then aspen persists very well in this area," says Taylor. "The different behavior in different areas then makes this a much more complex problem."

To provide a glimpse at the complexities of forest behavior, especially in the light of clear cutting, fire suppression and other environmental changes, Taylor, who studies a variety of aspects of the Basin's forests, has produced an online exercise, "Lands in Transition, Complex Decisions in the Lake Tahoe Basin." This explains some of the complexity of the Lake Tahoe Basin forests and is supported by the U.S. Department of Agriculture's Forest Service, The program, which is an interactive learning program, was produced by Penn State's Gould Center for Geography Education and Outreach and is available online at http://www.gouldcenter.psu.edu/lit or on CD by contacting Mark Johnson at mgjohnson@fs.fed.us by email.

"Because aspen are clones and regenerate vegetatively, some of the groves are 8,000 years old," says Taylor. "Aspen have rarely been observed to regenerate from seed, however they did after the recent Yellowstone National Park fires."

The Penn State researchers suggest that it may take a major event, such as a massive fire, to force the trees to reproduce sexually. Also, because aspen are shade intolerant, they need open spaces to grow properly.

"Aspen may require fire to continue to survive in healthy stands and prevent other species, especially confers, from taking over," Taylor says.


Story Source:

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


Cite This Page:

Penn State. "Survival Of Quaking Aspen Groves A Complex Problem." ScienceDaily. ScienceDaily, 8 August 2001. <www.sciencedaily.com/releases/2001/08/010808135343.htm>.
Penn State. (2001, August 8). Survival Of Quaking Aspen Groves A Complex Problem. ScienceDaily. Retrieved September 3, 2014 from www.sciencedaily.com/releases/2001/08/010808135343.htm
Penn State. "Survival Of Quaking Aspen Groves A Complex Problem." ScienceDaily. www.sciencedaily.com/releases/2001/08/010808135343.htm (accessed September 3, 2014).

Share This



More Plants & Animals News

Wednesday, September 3, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Snack Attack: Study Says Action Movies Make You Snack More

Snack Attack: Study Says Action Movies Make You Snack More

Newsy (Sep. 2, 2014) You're more likely to gain weight while watching action flicks than you are watching other types of programming, says a new study published in JAMA. Video provided by Newsy
Powered by NewsLook.com
Get A Mortgage, Receive A Cat — Only In Russia

Get A Mortgage, Receive A Cat — Only In Russia

Newsy (Sep. 2, 2014) The incentive is in keeping with a Russian superstition that it's good luck for a cat to be the first to cross the threshold of a new home. Video provided by Newsy
Powered by NewsLook.com
U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Sharks Off the Menu and on the Tourist Trail in Palau

Sharks Off the Menu and on the Tourist Trail in Palau

AFP (Sep. 2, 2014) Tourists in Palau clamour to dive with sharks thanks to a pioneering conservation initiative -- as the island nation plans to completely ban commercial fishing in its vast ocean territory. 01:15 Video provided by AFP
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