As mountain pine beetles march across the forests of western North America, these insects may kill millions of pine trees during a single outbreak. A rise in overall temperatures over the past several years has increased the range of mountain pine beetles, resulting in an epidemic and possibly making this mountain pine beetle infestation the largest forest-insect blight to occur in North America.
Dr. Francois Teste and colleagues from the University of Alberta in Canada have been investigating the effect of mountain pine beetle outbreaks on lodgepole pines in British Columbia. Teste and colleagues have discovered that seeds from cones on the forest floor may provide a viable seed bank for lodgepole pine regeneration following forest destruction by mountain pine beetles. Their research is published in a recent issue of the American Journal of Botany (http://www.amjbot.org/content/98/4/630.full).
Lodgepole pines, a variety of the pine species Pinus contorta, are a serotinous species—the seeds are only released from the cones in response to specific environmental conditions, in this case fire, rather than at the time of seed maturation. The seed bank of lodgepole pines is found in closed cones, which generally are located in the canopy. Following a mountain pine beetle outbreak, dead trees with canopy cones may remain standing for 10 to 15 years. However, scientists have observed a considerable increase in closed cones on the forest floor due to an increase in branch breakage after tree death. The viability of these canopy and forest-floor seeds and the likelihood that they will be able to contribute to forest regeneration has not been known.
Using germination techniques, Teste and colleagues assessed the viability of seeds from closed cones from both the canopy and forest floor of stands of trees 3 years, 6 years, and 9 years after mountain pine beetle outbreaks. These researchers found that closed forest-floor cones had high germination capacity (over 80%), but this germination capacity dropped to 45% for cones that were partly open. Although canopy cones have a >90% germination capacity a year, on average, after cone maturation, germination capacity steeply declined after 15 years and dropped to 50% after 25 years.
"Closed resin-bounded cones typical of serotinous pines can maintain (up to about 10-15 years) viable seed on dead trees even if the cones are partly open and/or in the forest floor," Teste said, "but of course the germination capacity does slowly decline with time." This is the first study demonstrating that there is a viable forest-floor seed bank for a serotinous pine species.
The serotinous adaptation of lodgepole pines allows for the regeneration of forests decimated by fire, but may be a hindrance to forests destroyed by mountain pine beetles. Although seed in closed cones may be viable following a mountain pine beetle outbreak, it cannot contribute to forest regeneration unless it is released from the cone, a process that would generally be triggered by fire.
"We can only speculate that it is a potential source for future regeneration if a ground fire or site preparation resurfaces the cones," Teste stated regarding the forest-floor seed bank. Teste's future research may focus on the impact of fire after mountain pine beetle outbreaks, specifically whether fire can promote regeneration from buried cones.
"With novel disturbances emerges novel responses to maintain ecosystem stability," Teste said.
Teste, François P., Victor J. Lieffers, and Simon M. Landhäusser. (2011). Viability of forest floor and canopy seed banks in Pinus contorta var. latifolia (Pinaceae) forests after a mountain pine beetle outbreak. American Journal of Botany 98(4): 630-637. DOI: 10.3732/ajb.1000252
The full article in the link mentioned is available for no charge for 30 days following the date of this summary at http://www.amjbot.org/content/98/4/630.full. After this date, reporters may contact Richard Hund at email@example.com for a copy of the article.
The Botanical Society of America (www.botany.org) is a non-profit membership society with a mission to promote botany, the field of basic science dealing with the study and inquiry into the form, function, development, diversity, reproduction, evolution, and uses of plants and their interactions within the biosphere. It has published the American Journal of Botany (www.amjbot.org) for nearly 100 years. In 2009, the Special Libraries Association named the American Journal of Botany one of the Top 10 Most Influential Journals of the Century in the field of Biology and Medicine.
For further information, please contact the AJB staff at firstname.lastname@example.org.
Richard Hund | EurekAlert!
Study relating to materials testing Detecting damages in non-magnetic steel through magnetism
23.07.2018 | Technische Universität Kaiserslautern
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.
The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
21.08.2018 | Materials Sciences
20.08.2018 | Information Technology
20.08.2018 | Life Sciences