Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Danger lurks underground for oak seedlings

05.03.2009
Scientists trying to understand why oaks are starting to disappear from North American forests may need to look just below the surface to find some answers.

Purdue University researcher Robert Swihart found that pine voles, small rodents that live underground, prefer oak roots to those of other commonly growing seedlings. The study identifies the rodents as a possible factor leading to high oak mortality rates that are threatening the resource base of the hardwood industry.

"You see a lot of mature oaks, but you don't see a lot of oaks in the understory beneath the canopy. If you don't see them there, you won't see mature oaks in 20 to 30 years," Swihart said. "We are facing a period in our history that could lead to a great crash in oak availability."

Swihart offered pine voles a selection of tree roots to eat in the laboratory, and they overwhelmingly gravitated toward oak roots. Voles caused more than twice as much damage to white oak roots than northern red oak and black cherry, and more than six times more damage to white oak than black walnuts. The voles snubbed yellow poplar roots altogether.

"Either the oak roots were much more nutritious and had higher energy content, or they contained fewer toxins, or some combination of those factors. Those are the main reasons an animal will choose one food item over another," Swihart said.

Swihart's study has been published in the current edition of the Canadian Journal of Zoology.

Under a variety of growing conditions, oak seedlings have comparatively high mortality rates, allowing other trees such as shade-tolerant maples and sun-loving, fast-growing tulip poplars to make up larger percentages of hardwood forests. Most of the studies on why oaks have a hard time regenerating have focused on competition from other seedlings, the use of acorns as food for small animals above the ground and the use of oak seedlings as food for deer.

"A lot of the focus has been on what's occurring above ground. We decided to look at what's going on below the ground," Swihart said. "We know pine voles can do a lot of damage in apple orchards, but there is little, except for a few anecdotal accounts, of what they do in their natural environment."

Swihart got the idea for his study from Ron Rathfon, a Purdue Extension forestry specialist in southern Indiana who has studied oak mortality issues. Rathfon found in 2006 that animals, later determined to be pine voles, had been responsible for killing at least 19 percent of the dead oak seedlings observed in his study area. He said the voles, which are common to eastern deciduous forests, were likely responsible for the majority of oak seedling mortality because many seedlings went missing, suggesting the voles had eaten or removed the entire plants.

There is little overall loss of oak forest to date, but Rathfon said that might change if foresters, the timber industry and landowners do not implement practices that better manage long-term oak growth and development.

"We do see some data that more shade-tolerant trees - particularly sugar maples - are becoming more prominent," Rathfon said. "It is a gradual, subtle shift that is taking place."

Swihart said the loss of oaks would have other serious effects besides losses to the hardwood industry.

"Oak mortality could reduce the capacity of hardwood forests to support wildlife populations that rely on oaks for food - everything from deer and turkey down to mice and songbirds," Swihart said.

Purdue undergraduate student Leslie Schreiber worked with Swihart on the pine vole study. Funding for the work came from Purdue Agriculture.

Writer: Brian Wallheimer, (765) 496-2050, bwallhei@purdue.edu
Sources: Robert Swihart, (765) 494-3590, rswihart@purdue.edu
Ron Rathfon, (812) 678-5049, ronr@purdue.edu
Ag Communications: (765) 494-2722;
Beth Forbes, forbes@purdue.edu

Brian Wallheimer | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Agricultural and Forestry Science:

nachricht Light green plants save nitrogen without sacrificing photosynthetic efficiency
21.11.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign

nachricht Filling intercropping info gap
16.11.2017 | American Society of Agronomy

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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Previous evidence of water on mars now identified as grainflows

21.11.2017 | Physics and Astronomy

NASA's James Webb Space Telescope completes final cryogenic testing

21.11.2017 | Physics and Astronomy

New catalyst controls activation of a carbon-hydrogen bond

21.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>