News and Events
If you want to record bat calls in summer, go early. Detectors recorded significantly more high-quality call files during late June and early July than August. USDA Forest Service research ecologist Susan Loeb and colleagues published results from a bat detection survey in Acta Chiropterologica.
The North American Bat Monitoring Program (NABat) was designed to meet local needs, and it must do that if locals are expected to continue participating. NABat launched in 2015 as a collaborative, long-term program to assess the status and trends of North American bats at local, regional, and range-wide scales. NABat developed out of a national working group chaired by USDA Forest Service research ecologist Susan Loeb.
Bats are important components of healthy forests and provide critical ecological services across numerous different ecosystems. For decades, bat populations throughout the southern U.S. have been declining due to habitat disturbance and loss.
By lying on your back under an oak tree, you can look up and estimate its number of acorns. But why? “A lot of state wildlife agencies do acorn surveys annually because hunters want to know crop sizes, which fluctuate like crazy from year to year, among different oak species, and among locations,” says USDA Forest Service scientist Katie Greenberg. “Big acorn crops can help to increase reproduction and survival of deer, grouse, turkeys, and other game species that eat acorns. In fact, acorns are considered a keystone species because mice and squirrels also benefit from big acorn crops, and so do other animals – like hawks, foxes, and bobcats – that in turn eat them. Foresters are also interested, since acorns are the seeds for future baby oak trees.”
Acorns feed birds, bears, deer, and many small mammals. But the big oak trees that produce those acorns are also harvested to become timber. In managing hardwood forests, there’s a potential trade-off between harvesting oak trees for their valuable wood and reducing the number of oak trees left to produce acorns. To help determine a good balance, USDA Forest Service research ecologist Katie Greenberg counted acorns and measured tree crown area and trunk diameter growth rates of five eastern oak species in shelterwoods (where many oaks had been harvested) and mature mixed-oak forests. Results of the 17-year study were published in Forest Ecology and Management.
About half of southern forests are a mix of oaks and pines growing side by side. In the past, getting rid of either the oaks or the pines had been a common management goal. “Pine plantations – stands with no oaks – have become one of the most recognizable symbols of forest management,” says John Willis, a USDA Forest Service researcher.
Oaks are keystone species in forests across the eastern U.S. However, oak reproduction has been declining since at least the 1970s — old oaks still dominate the overstory, but a younger generation is not coming in behind. White oak, in particular, is valuable to wildlife and wood-dependent industries such as barrel, furniture, and cabinet making. Scientists are trying to find out what influences white oak reproduction and survival so managers can sustain it into the future.
A free online course – An Introduction to the American Chestnut – is now available. The course covers chestnut taxonomy, silvics, historical importance, ecology, and its demise. A second course in development will cover American chestnut restoration and management.
On November 3, about forty people from the USDA Forest Service and The American Chestnut Foundation (TACF) gathered virtually. It was the second biennial plan of work meeting between TACF and SRS.
White oak (Quercus alba) is an incredibly important species, anchoring ecosystems and economies. Current demand for white oak is surging due to its use in making barrels to support a growing spirits industry. Thus, there’s a real need understand the best tools to promote and sustain white oak in forests to support both economic and ecosystem benefits that the species provides.
For the first time since 2002, scientists and land managers met to share knowledge on sustaining and conserving oak forests in the eastern U.S. The oak symposium was held October 2017 in Knoxville, Tennessee and hosted by The University of Tennessee Department of Forestry, Wildlife, and Fisheries. The meeting featured 33 invited speakers, an audience discussion period, a poster session, and a field trip showcasing collaborative research.
On August 2, 2020, Glendon W. Smalley died at his home in Sewanee, Tennessee. He was 92. Smalley was an Emeritus scientist with the Southern Research Station.
In July, state forest agencies, National Forest System managers, and others convened digitally for the Upland Hardwood Silvicultural Workshop. The virtual workshop, organized by the USDA Forest Service Upland Hardwood Ecology and Management Research Work Unit, consisted of half-day sessions in which natural resource practitioners learned the most up-to-date hardwood forest management practices based on scientific research from across the southeastern U.S.
To increase the prescribed “burn window” for reaching restoration goals, land managers are now burning during winter (the dormant season) as well as spring and summer (the growing season) and fall. Management goals often include fuel reduction, oak regeneration, habitat improvement for target wildlife species, and forest restoration to conditions once created by Native Americans and Euro-American settlers.
In 1995, Hurricane Opal toppled trees throughout the South, including parts of the southern Appalachians. Wind is a common canopy disturbance in upland oak-hickory forests, but little has been reported on naturally formed large gaps of more than six trees where a partial canopy remains. With Erik Berg, SRS researchers Stanley Zarnoch and Henry McNab observed and modeled tree survivorship in and around 12 large gaps created by the hurricane. The scientists monitored the sites for 20 years. Many survivorship studies only last for five years or so, which may not be long enough to understand survivorship dynamics.
This workshop was designed to provide foresters and other natural resource practitioners with the most state-of-the-art, science-based information necessary to sustainably manage upland hardwood ecosystems of the Central Hardwoods Region of the US for a wide variety of goods and services.
You can view the recorded presentations and course materials from each day!
USDA Forest Service and University of Florida scientists partnered to monitor reptiles and amphibians before and after growing season (spring and summer) and dormant season (winter) prescribed burns in longleaf pine sandhills in a study on the Ocala National Forest in Florida. The research team recorded the number of animals captured, the number of species (species richness), and species diversity before and after several prescribed burns. Populations of six amphibian and six reptile species were monitored over the course of several prescribed burns during a 24-year period.
Disturbance – from fire and subsistence living to widespread exploitative logging – enabled the growth of oak (Quercus) forests across the eastern U.S. These disturbances are not common today. Reduced disturbance, coupled with a long-term increase in moisture availability has been good for non-oak trees, which establish and grow under the older oak canopy – and inhibit oak seedling growth.
In February 2020, USDA Forest Service scientist Stacy Clark planted 720 white oak (Quercus alba) seedlings on the Pisgah National Forest in western North Carolina. “White oak is declining in abundance across the eastern U.S., and we are concerned that wildlife species and industries around cooperages, distilleries, and flooring will be negatively affected without proactive forest management,” says Clark. “We established this study to provide landowners with practical options for maintaining white oak trees in their forests.”
The study of how, or if, a species is genetically adapted to its environment is called genecology. USDA Forest Service plant physiologists Kurt Johnsen and John Butnor, with biological scientist Chris Maier, are conducting genecology and molecular genetic studies across the range of red spruce (Picea rubens) in a cooperative study with Steve Keller of the University of Vermont.
On March 3 and 4, 2020, about 25 silviculturists, foresters, fire management officers, timber specialists, and other USDA Forest Service experts gathered for a two-day workshop on shortleaf pine (Pinus echinata). In the southern Appalachians, shortleaf pine restoration is a major priority for national forests and others. The species has an extensive range but its acreage has declined by more than half over the past few decades.
Oak regeneration is an oft-discussed topic in forestry. The trees aren’t sustainably generating in many upland temperate forests due to a variety of factors — including the fact that they are less competitive than other, more sun-loving species such as tulip poplar. One way that forest managers are responding to this issue is artificial oak regeneration. This approach consists of sowing acorns in a nursery, growing seedlings for one year, and then planting the best seedlings in areas where the species isn’t regenerating well on its own.
Meet Cathryn (Katie) H. Greenberg, a research ecologist with the Upland Hardwood Ecology and Management unit located at the Bent Creek Experimental Forest in Asheville, North Carolina. Her research focuses on how disturbances, both natural and management-based, affect animal communities and food resources for wildlife in forests.
When a cold snap killed the Eucalyptus benthamii saplings, no one was surprised. E. benthamii is one of the most cold-tolerant of approximately 700 Eucalypts. Still, it is maladapted to the North Carolina Piedmont, according to a recent USDA Forest Service study published in Forest Science.
The American chestnut (Castanea dentata) was a keystone tree species in the eastern U.S., once found in the forest overstory from Maine to Georgia. The loss of the “mighty giant” to chestnut blight (Cryphonectria parasitica), a fungal disease accidentally imported from Asia in the early 1900s, reduced the once dominant chestnuts to remnant understory sprouts.
“Researchers haven’t really studied cliffs as foraging areas for bats,” says USDA Forest Service scientist Susan Loeb. “When so little is known about that habitat, it can be hard to gauge the impacts of different uses or management plans.” Rapid growth in technical climbing has put rock climbers in the same spots as bats. How compatible are the two?
Used incorrectly, fire can degrade wood quality and its value as timber. When should managers use prescribed fire in hardwood stands? prescribed-fire-north-alabamaA dormant season prescribed fire burns through a hardwood stand in northern Alabama. Photo by Callie Schweitzer, USFS. “I field a lot of questions from state and local partners about the long-term effects of using prescribed fire in hardwood stands,” says USDA Forest Service scientist Callie Schweitzer.
Amphibians and reptiles tend to be most active during the spring and summer, when it’s warmer. A recent USDA Forest Service study compared how herpetofauna respond to prescribed fires conducted during the growing season – when vegetation is actively growing – versus those in dormant season months.
Drive down Highway 7 in northern Arkansas, winding through the Ozark National Forest, and you may glimpse evidence of recent fire: scorched grass, darkened tree bark, maybe even a lingering wisp of smoke.
Traces of prescribed burning can be seen throughout the South. Prescribed fire is a critical tool for forest restoration.
A new study led by USDA Forest Service research forester Tara Keyser examines the effects of prescribed burning on the mortality of ten upland hardwood species found in the eastern United States.
Upland hardwood forests mature slowly – it can take as long as a century. It can also take years to answer research questions about these forests, which are often dominated by oaks and hickories.
In 2003, the U.S. Forest Service Southern Research Station (SRS), Northern Research Station, and Southern Region (Region 8) of the National Forest System initiated a long-term cooperative project on the Daniel Boone National Forest in Kentucky.
“Oaks don’t seem to be regenerating at the rate they are declining and finally dying,” observes Katie Greenberg, research ecologist at Bent Creek Experimental Forest.
The U.S. Forest Service had put its station at Bent Creek in 1925 because the area had been deemed one of the best examples of an Appalachian mixed hardwood forest.
Studies show that bats eat enough insect pests to save the U.S. corn industry more than $1 billion a year in crop damage and pesticide costs, and more than $3 billion per year to all agricultural production including forests. Federal agencies, universities, private researchers, as well as state agencies and tribes are working together to help save bats affected by WNS.
Over the past few decades, scientists have become increasingly concerned about amphibians. “Populations of many frog and toad species have declined,” says U.S. Forest Service research ecologist Katie Greenberg. “The global decline highlights the need to monitor frogs and toads where they live.”
Meet SRS scientist Callie Schweitzer, a research forester with the Upland Hardwood Ecology and Management Research Unit in Huntsville, Alabama. She received her doctorate and master’s degrees in Forest Resources and Ecology from Pennsylvania State University.
When ephemeral wetlands swell with water, frogs and toads congregate to breed and lay their eggs,which hatch into tadpoles. “That’s risky business,” says U.S. Forest Service research ecologist Katie Greenberg. “Wetlands could dry before tadpoles metamorphose into juveniles.”
By the 1950s, two non-native pathogens had killed almost all American chestnut trees. “There’s a lot of interest in breeding a chestnut that looks like American chestnut, but has the disease resistance of Chinese chestnut,” says U.S. Forest Service research forester Stacy Clark. “However, there hasn’t been much research on reintroducing disease-resistant trees.”
The mighty oak is a critical component of southern forests—for wildlife habitat, acorn production, and hardwood timber—but forests are changing, and its future is uncertain.
Rafinesque’s big-eared bat (Corynorhinus rafinesquii) is considered a rare and sensitive species. The bats are small, with a body length of three to four inches, ears just over one inch, a wingspan just shy of a foot, and they weigh around half an ounce — less than a slice of bread.
SRS research entomologist Bud Mayfield was relieved to find that defoliation on an American chestnut planting site was not as severe as expected. Mayfield and SRS research forester Stacy Clark are coauthors on a paper in the Journal of Insect Science that describes a study they conducted with Ashley Case, an adjunct lecturer at the University of North Carolina at Asheville.
Carbon is the foundational element of life, and trees use atmospheric carbon dioxide to grow. “Trees can partially offset carbon dioxide emissions,” says U.S. Forest Service plant physiologist John Butnor. “Trees pull carbon out of the atmosphere and store it for long periods of time.”
A plant module developed in partnership by the U.S. Forest Service Southern Research Station and the Eastern Band of Cherokee Indians is now available online for teachers to download and use with K-12 students. The module integrates current science-based knowledge with the traditional knowledge passed down from generation to generation of Cherokee.
The new Women in Science series features women scientists from across the Southern Research Station (SRS)–their education, career paths, challenges, achievements, and inspirations.
Management on public lands across the eastern US is increasingly focused on the restoration of resilient structures and species compositions, with prescribed burning being the primary tool by which many landscape-level restoration efforts are implemented.
Oak woodlands are typically made up of large, widely spaced trees. Flowering plants, grasses, and other herbaceous species flourish in the understory. “Many public lands managers want to create woodland habitats,” says U.S. Forest Service research forester Stacy Clark. “They provide numerous ecological benefits.”
At the U.S. Forest Service’s Southern Research Station in Asheville, Tara Keyser has spent years working on the vexing problem of oak regeneration. And since 2009, she’s pushed for a long-term study to determine whether an innovative forest management approach can help this species regenerate.
Named for Henry R. Koen, forest supervisor of the Ozark National Forest during the first half of the 20th century, the experimental forest was set aside to develop scientific principles for forest management. At 720 acres, the Koen is the smallest of the 19 experimental forests managed by Southern Research Station.
A recent conference titled “Measure Locally, Respond Globally” brought 35 journalists to Asheville, North Carolina, to learn more about what researchers and entrepreneurs are doing to address climate change — and may have also sparked a new nickname for the city of Asheville.
The Southern Forest Futures Project, a multi-agency effort led by the U.S. Forest Service, aimed to forecast and interpret changes in southern forests under multiple scenarios over the next several decades.
The project also included a suite of sub-regional reports designed to explore futures on a smaller, more focused scale. Tara Keyser, research forester with the Upland Hardwood Ecology and Management unit, was lead author of the sub-regional report that describes possible futures and management implications across the U.S. Appalachian-Cumberland highland.
A recently published book edited by U.S. Forest Service researcher Katie Greenberg and Western Carolina University professor Beverly Collins offers detailed science-based information about the history of natural disturbances in the Central Hardwood Region of the U.S., and provides insight for managers and ecologists on managing the area’s forests.
Until recently, most American chestnut studies took place in labs or in orchards, as scientists focused on developing a blight-resistant hybrid that would grow like pure American chestnut.
After World War I, when the Forest Service sought to establish an experimental station on a site that represented the diversity of the Southern Appalachian Mountains, the Bent Creek area of western North Carolina seemed the logical choice.
There’s a tendency to think of the hardwood forests of the South as pristine, undisturbed, and unchanging. But forests are constantly changing, which is a good thing for disturbance-dependent species that require open structural conditions created immediately after forest disturbances or at some point early in the process of recovery.
In the Coastal Plain of South Carolina, Rafinesque’s big-eared bats often roost in tree hollows throughout the year. “Bats spend a good portion of their lives in roosts,” says U.S. Forest Service scientist Susan Loeb. “Roosts protect bats from predators, and are where bats interact socially, mate, and raise young.”
The U.S. Forest Service Southern Research Station (SRS) and the Eastern Band of Cherokee Indians (EBCI) recently partnered to develop learning modules for children attending EBCI’s Snowbird Youth Center in Robbinsville, North Carolina. The youth center is part of the Boys and Girls Clubs of Cherokee.
A new book edited by U.S. Forest Service researcher Katie Greenberg and Western Carolina University professor Beverly Collins offers detailed science-based information about the history of natural disturbances in the Central Hardwood Region of the U.S., and provides insight for managers and ecologists on managing the area’s forests.
Spending Christmas with the Forest Service led Henry McNab, research forester, to become one of SRS’s longest serving employees. McNab started his career in Fort Myers, Florida, working for Jim Bethune measuring pine trees around Christmas time. He called the two-week stint with the Forest Service “kind of serendipitous” in helping lead him to where he is today. While he started out measuring pine trees, he now studies hardwood forests. He is located at the Upland Hardwood Ecology and Management research unit in Asheville, North Carolina. On his own admission, he has probably worked for more project leaders and research station directors than most people.
On March 9th, U.S. Forest Service scientist Susan Loeb and numerous partners were recognized with the Forest Service Wings Across the Americas Research Award for their contributions to the North American Bat Monitoring Program (NABat).
Establishment of American chestnuts (Castanea dentata) bred for blight (Cryphonectria parasitica) resistance: influence of breeding and nursery grading
Scientist publishes on the first field testing of American chestnuts bred for blight resistance.
Scientists present in the “Proceedings of the 17th Biennial Southern Silvicultural Research Conference.”
Scientists present in the proceeding “Wildland Fire in the Appalachians: Discussions Among Managers and Scientists.”
For almost a hundred years, foresters have dreamed of the American chestnut’s return. “As the 21st century unfolds, the chestnut restoration goal may be closer to reality,” says U.S. Forest Service Southern Reseearch Station (SRS) scientist Stacy Clark.
Keeping forests healthy is better than trying to restore them after droughts or insect outbreaks have already killed trees, but identifying future threats is sometimes a challenge. Not so in the Daniel Boone National Forest in the Cumberland Plateau area of Kentucky. Oaks dominate the area, but they are under stress and susceptible to decline, while invasive gypsy moths expand their range every year and will probably reach the Forest within the next several decades. The moth larvae eat the leaves of trees and shrubs, and defoliation could interact with oak decline to kill many trees in the Cumberland Plateau.
Some acorns go on to become the next generation of oak trees, but others are eaten by birds, bears, rodents, and deer. Rodents are in turn eaten by carnivores, and deer browsing affects which kinds of plants become established and survive.
Over 60 land managers, scientists, students, and professors attended a recent symposium on natural disturbances and historic range of variation. The symposium was held at the annual meeting of the Association of Southeastern Biologists, and organized by Cathryn Greenberg, project leader of the U.S. Forest Service Southern Research Station Upland Hardwood Ecology and Management unit, and Beverly Collins, a professor at Western Carolina University.
The Blue Valley Experimental Forest (Blue Valley) lies in southwest North Carolina in the Nantahala National Forest. Located in Macon County, near the point where North Carolina meets Georgia and South Carolina, the experimental forest was established in 1964. At 1,300 acres, it is the smallest of the three experimental forests in North Carolina and the second smallest of the 19 managed by U.S. Forest Service Southern Research Station (SRS).