"The study marks the first time that scientists have tracked the short-term effects hemlock woolly adelgid infestations are having on the forest carbon cycle," said Chelcy Ford, SRS ecologist and co-author of the paper.
Eastern hemlock, a keystone species in the streamside forests of the southern Appalachian region, is already experiencing widespread decline and mortality because of hemlock woolly adelgid (a tiny nonnative insect) infestation. The pest has the potential to kill most of the region's hemlock trees within the next decade. As a native evergreen capable of maintaining year-round transpiration rates, hemlock plays an important role in the ecology and hydrology of mountain ecosystems. Hemlock forests provide critical habitat for birds and other animals; their shade helps maintain the cool water temperatures required by trout and other aquatic organisms in mountain streams.
Scientists conducted the study in mixed hardwood forests along the edges of two streams at the SRS Coweeta Hydrologic Laboratory, a 5,600-acre research facility and experimental forest in the Nantahala Mountain Range of western North Carolina.
Researchers compared rates of decline of adelgid-infested hemlock trees to a small number of girdled (severely wounded the bark of a tree to initiate tree mortality) trees that were not infested. Researchers tracked changes in the carbon cycle of these hemlock stands over a 3-year period. Scientists measured components of the forest carbon cycle – including tree growth, leaf litter and fine root biomass, and soil respiration – over the 3-year period.
"While we expected that girdled trees would decline quickly, we were surprised to find that hemlock declines just as quickly from adelgid infestation," said Ford. "This research shows that hemlock woolly adelgid infestation is rapidly impacting the carbon cycle in these tree stands. The study also supports the widely held belief that adelgid-infested hemlock trees in the South are declining much faster than the reported 9-year decline of some infested hemlock trees in the Northeast."
The study showed, among other things, that very fine roots in the girdled and hemlock woolly adelgid-infested plots declined by 38 percent and 22 percent, respectively, during the 3-year period. In addition, in the first year after girdling and infestation, researchers found soil respiration was approximately 20 percent lower than they expected.
The authors suggest that infrequent frigid winter temperatures in the southern Appalachians may not be enough to suppress adelgid populations. The authors believe this could be one explanation of why infested hemlocks appear to be declining faster in the South than in the Northeast. The authors also point out that other tree species are quick to occupy the space given up by their dying hemlock neighbors.
"Perhaps because of increased light in the canopy and reduced competition for soil nutrients and water, other species are already increasing their growth," said Ford. "We'll continue to monitor this, but, it's still too early to predict just how different these forests will look 50 or 100 years from now."
Stevin Westcott | EurekAlert!
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
28.03.2017 | Life Sciences
28.03.2017 | Information Technology
28.03.2017 | Physics and Astronomy