Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Handful of Heavyweight Trees Per Acre Are Forest Champs

04.05.2012
Big trees three or more feet in diameter accounted for nearly half the biomass measured at a Yosemite National Park site, yet represented only one percent of the trees growing there.

This means just a few towering white fir, sugar pine and incense cedars per acre at the Yosemite site are disproportionately responsible for photosynthesis, converting carbon dioxide into plant tissue and sequestering that carbon in the forest, sometimes for centuries, according to James Lutz, a University of Washington research scientist in environmental and forest sciences. He's lead author of a paper on the largest quantitative study yet of the importance of big trees in temperate forests being published online May 2 on PLoS ONE.

"In a forest comprised of younger trees that are generally the same age, if you lose one percent of the trees, you lose one percent of the biomass," he said. "In a forest with large trees like the one we studied, if you lose one percent of the trees, you could lose half the biomass."

In 2009, scientists including Lutz reported that the density of large-diameter trees declined nearly 25 percent between the 1930s and 1990s in Yosemite National Park, even though the area was never logged. Scientists including co-author Andrew Larson of the University of Montana, also have found notable numbers of large trees dying in similar areas across the West.

Because of this, scientists have been keen to study a plot large enough to detect forest ecosystem changes involving large trees, including the effects of climate variability and change, possible culprits in the declines, Lutz said.

The new 63-acre study site in the western part of Yosemite National Park is one of the largest, fully-mapped plots in the world and the largest old-growth plot in North America. The tally of what's there, including the counting and tagging of 34,500 live trees, was done by citizen scientists, mainly undergraduate college students, led by Lutz, Larson, Mark Swanson of Washington State University and James Freund of the UW.

Included was all above-ground biomass such as live trees, snags, downed woody debris, litter and what's called duff, the decaying plant matter on the ground under trees. Even when big trees die, they continue to dominate biomass in different ways. For example, 12 percent of standing snags were the remains of large-diameter trees, but still accounted for 60 percent of the total biomass of snags.

Live and dead biomass totaled 280 tons per acre (652 metric tons per hectare), a figure unmatched by any other forest in the Smithsonian Center for Tropical Forest Science network, a global network of 42 tropical and temperate forest plots including the one in Yosemite.

Trees in the western U.S. with trunks more than three feet across are typically at least 200 years old. Many forests that were heavily harvested in the 19th and 20th centuries, or those that are used as commercial forest lands today, don't generally have large-diameter trees, snags or large wood on the ground.

One implication of the research is that land managers may want to pay more attention to existing big trees, the co-authors said. Last year in the Yosemite National Park, for example, managers planning to set fires to clear out overgrown brush and densely packed small trees first used data from the study plot to figure out how many large trees to protect.

"Before the fires were started, crews raked around some of the large trees so debris wouldn't just sit and burn at the base of the tree and kill the cambium, the tissue under the bark that sustains trees," Lutz said.

In some younger forests that lack big trees, citizens and land managers might want to consider fostering the growth of a few big-trunked trees, Lutz said.

Another finding from the new work is that forest models based either on scaling theory or competition theory, which are useful for younger, more uniform forests, fail to capture how and where large trees occur in forests.

"These trees started growing in the Little Ice Age," Lutz said. "Current models can't fully capture the hundreds of years of dynamic processes that have shaped them during their lifetimes."

The research was funded by the Smithsonian Center for Tropical Forest Science.

For more information:
Lutz, 206-616-3827, jlutz@uw.edu
Facebook page for Yosemite plot
http://www.facebook.com/pages/Yosemite-Forest-Dynamics-Plot/117620576445
After embargo lifts 2 p.m. PT (5 p.m. ET), May 2, article is available at
http://dx.plos.org/10.1371/journal.pone.0036131
Suggested websites
Jim Lutz
http://faculty.washington.edu/jlutz/
PLos One
http://www.plosone.org/home.action
Andrew Larson
http://www.cfc.umt.edu/Personnel/Details.php?ID=1710
Homepage for Yosemite plot
http://depts.washington.edu/yfdp/
Yosemite National Park
http://www.nps.gov/yose/index.htm
Citizen scientists
http://depts.washington.edu/yfdp/peoplePage.php?q=2011
Mark Swanson
http://www.natural-resources.wsu.edu/people/faculty/swanson.html
Smithsonian Center for Tropical Forest Science
http://www.ctfs.si.edu/

Sandra Hines | Newswise Science News
Further information:
http://www.uw.edu

More articles from Agricultural and Forestry Science:

nachricht New parsley virus discovered by Braunschweig researchers
17.05.2019 | Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH

nachricht Franco-German research initiative on low-pesticide agriculture in Europe
16.05.2019 | Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V.

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: New studies increase confidence in NASA's measure of Earth's temperature

A new assessment of NASA's record of global temperatures revealed that the agency's estimate of Earth's long-term temperature rise in recent decades is accurate to within less than a tenth of a degree Fahrenheit, providing confidence that past and future research is correctly capturing rising surface temperatures.

The most complete assessment ever of statistical uncertainty within the GISS Surface Temperature Analysis (GISTEMP) data product shows that the annual values...

Im Focus: The geometry of an electron determined for the first time

Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.

The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

On Mars, sands shift to a different drum

24.05.2019 | Physics and Astronomy

Piedmont Atlanta first in Georgia to offer new minimally invasive treatment for emphysema

24.05.2019 | Medical Engineering

Chemical juggling with three particles

24.05.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>