by Staff Writers
Asheville NC (SPX) Jul 19, 2012
U.S. Forest Service scientists have found that prescribed fires with the heat insulation of leaf litter and soil can help restore oak ecosystems. Forest Service researchers are helping land managers find the best time to use prescribed fire when oak regeneration from acorns is a concern. "Acorns inside the leaf litter or in the soil are for the most part protected from fire," says Cathryn Greenberg, U.S. Forest Service Southern Research Station (SRS) researcher and lead author of the study published in July in the journal Forest Ecology and Management.
"However, when acorns lie on top of the leaf litter, even low intensity surface fires will kill most of them."
Prescribed fire is increasingly used as a tool in oak ecosystem restoration, with the goal of reducing competition and creating light and seedbed conditions that help oak seedlings germinate and flourish. Forest Service researchers are helping land managers find the best time to use prescribed fires when oak regeneration from acorns is a concern.
To see how fire affected acorns, researchers placed nuts on the leaf litter surface, inside the duff (leaf litter plus smaller fragments of plant material), and underneath the duff, about 2 inches into the soil. The temperature of the prescribed burns, measured just above the surface of the leaf litter, ranged from less than 174 degrees F to almost 700 degrees F.
After the burn, researchers retrieved the acorns and placed them in ideal conditions for germination. "Almost all the acorns that were on the leaf litter surface and exposed to fire died," says Greenberg. "However, acorns in the duff or in the soil were better protected from high temperatures, and generally unaffected by low intensity fires."
When acorns fall to the forest floor they don't stay on top of the leaf litter too long. Squirrels, jays, chipmunks and mice bury acorns, or they settle into the litter because of weather, falling leaves and gravity. Once acorns are blanketed by leaf litter or soil, low-intensity burns are usually safe.
However, land managers should consider the timing and size of acorn crops, as well as the forest floor condition when determining the timing and frequency of prescribed burning. "Frequent burning that reduces litter and duff depth could compromise the availability of 'safe sites' where acorns are insulated from high fire temperatures," says Greenberg.
Access the full text of the article here
U.S. Forest Service
Forestry News - Global and Local News, Science and Application
Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.
Canada claims win in pine beetle lumber dispute with US
Ottawa (AFP) July 18, 2012
Canada claimed a victory on Wednesday in a dispute with the United States over softwood lumber, after a tribunal ruled it had not violated a trade accord by selling beetle-blemished logs at low prices. "We applaud the tribunal's decision in favour of our lumber industry," Trade Minister Ed Fast said in a statement. An international arbitrator earlier dismissed a US complaint that Canada ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|