In the News

In the 1960s, forests across New England were declining. The decline affected red spruce and balsam fir forests, especially those at high elevations. “Researchers agreed that acidic deposition was the primary cause of the decline,” says Eastern Threat Center research ecologist Steve McNulty. “However, most of the decline was blamed on sulfur not nitrogen deposition, and the mechanisms for the mortality were unclear.” After a regional field survey across high elevation spruce-fir forests, McNulty and his colleagues decided to conduct a study on Mount Ascutney, in Vermont. They hypothesized that chronic low doses of nitrogen could cause the forest decline. In 1988, the scientists established research plots and treated some of them with a nitrogen-rich fertilizer. Some plots received 35 pounds of nitrogen per acre each year, and others received 70 pounds of nitrogen per acre each year (rates that were equal to nitrogen deposition occurring in parts of Europe at the time). After a few years, the local nitrogen cycle was affected. Results were recently published in the journal Science of the Total Environment. Read more in CompassLive...

Wildfires burned within about ten miles of the village of Cashiers in southwestern North Carolina in fall 2016. The proximity and drifting smoke were eye-opening reminders about fire’s role in the landscape for this small community surrounded by the Nantahala National Forest. Eastern Threat Center research ecologist Steve Norman recently spoke to a group of Cashiers residents and other interested individuals about the region’s past fire-climate relationships. He also discussed the unique drought conditions in fall 2016 that contributed to an epic fire season in the Southeast and how fire hazards change with fuels and extreme weather across seasons and from year to year. “Cashiers and the extensive nearby forestland are especially rich in terms of biodiversity, but the area has also seen its share of development in areas that are fire-prone, heightening concerns about community preparedness in the event of wildfire,” says Norman. Southern Research Station research ecologist Katie Greenberg, Josh Kelly (MountainTrue), and Laurel Kays (Southwestern NC Resource Conservation & Development Council) also spoke to the group about aspects of the region’s fire risks and post-fire ecological responses. The event was part of the Village Nature Series, a public lecture series now in its ninth year, sponsored by Cashiers’ Village Green and the Highlands-Cashiers Land Trust.

A site targeted for ecological restoration is a piece of a larger puzzle. “Many scientists and managers recognize the importance of the surrounding landscape because this context often determines the success of restoration activities. However, the prioritization of restoration sites based on this context isn’t yet a common practice,” says Eastern Threat Center research ecologist Kurt Riitters. A new database could change that. Riitters is among research partners who ran U.S. land cover data through software that recognizes and categorizes spatial patterns. The researchers looked for relatively small sites with patterns indicating a potential need for revegetation that were also close to other sites with existing natural vegetation. They identified more than 1.1 million candidates, most highly concentrated in the East and the Great Plains. To help restoration ecologists narrow their focus within this set of candidates, researchers added information about site characteristics for each candidate in the database. They included the candidate’s area, connection to surrounding sites, roads, streams, soils, and land cover—17 attributes in all—that provide important landscape context. Natural resource managers facing limited funds and time can use the database to plan their efforts in order to maximize benefits to society and the environment. A paper published in Ecological Restoration describes the development of the database and its application to real-world planning at the state level. Read more in CompassLive...

When the redbay ambrosia beetle, native to Asia, was first detected in coastal Georgia in 2002, it didn’t set off any alarm bells. All ambrosia beetles carry fungi that serve as a food source for adults and larvae living in tunnels under the bark of host trees and shrubs. Usually, these fungi aren’t harmful, but the Raffaelea lauricola fungus carried by the redbay ambrosia beetle is one major exception. It causes laurel wilt, a swift killer that has spread to nine states and killed as many as 300 million redbay trees since it was identified in 2004. But how did the epidemic start, and why does that matter so much now? Eastern Threat Center research ecologist Frank Koch is among university and Forest Service researchers who provide some hindsight in a study that was recently published in Biological Invasions. They hypothesized that the tiny beetle and its companion fungus began their rampage after a single introduction, likely near the Port of Savannah. Between 2000 and 2012, the researchers collected 14 female beetles in baited traps places in infested redbay stands in Florida, Georgia, Louisiana, and South Carolina. They also collected 57 fungal samples in these same states between 2004 and 2010. After extracting and sequencing DNA, they discovered that all the beetle samples were genetically the same, indicating they shared a common ancestor. Researchers also found that 95% of the fungal samples had identical genes, further supporting their hypothesis that a single introduction of a redbay ambrosia beetle carrying the R. lauricola fungus was all it took to set off the laurel wilt epidemic in the United States. Read more in CompassLive...

Observers know green leaves don’t appear at the same time every spring, nor do they begin to fade away at the same time every fall. To gain a better understanding of the variation in the timing of spring and autumn across a diverse mountain landscape, Eastern Threat Center research ecologist Steve Norman led a study focused on the Great Smoky Mountains National Park. Along with Center research ecologist Bill Hargrove and biological scientist Bill Christie, he analyzed changes in vegetation greenness — or land surface phenology — from satellite-based data collected daily between 2000 and 2015. Researchers used the ForWarn monitoring and assessment tool to view the data on maps generated every eight days. Findings, recently published in a special issue of Remote Sensing, indicate that the timing of spring vegetation greenup and autumn browndown in the Park can vary by about two and a half weeks each year. In general, spring warmth accelerates vegetation greenup, and early autumn warmth delays browndown. Land surface phenology in the Park may also depend on cross-seasonal weather. And elevation appears to drive greenup and browndown more so than moisture. Study results can help resource managers understand ecosystem productivity, anticipate wildlife movement and behavior, and prepare for potential disturbances, such as growing season insect defoliation and wildfire activity. This insight is also useful for planning around the timing of spring flowering and autumn foliage, which are huge draws for recreation-based tourism and critical for local economies. Read more in CompassLive...

What do water locust, Texas walnut, chalk maple, pyramid magnolia, two-wing silver bell, and butterbough all have in common? They’re among the U.S. tree species most vulnerable to climate change, according to a study by North Carolina State University scientist Kevin Potter (an Eastern Threat Center cooperator), U.S. Forest Service Southern Region geneticist Barbara Crane, and Center research ecologist Bill Hargrove. Using a framework known as Project CAPTURE (Conservation Assessment and Prioritization of Forest Trees Under Risk of Extirpation), the researchers analyzed the traits of 339 U.S. tree species and predictions of climate-related pressure on each species. They then listed each species in one of seven vulnerability classes based on its exposure, sensitivity, and capacity to adapt to a changing environment. Of the 35 tree species listed in the highest vulnerability class, 24 are mostly found in the Southeast. “As we continue to analyze additional tree species and updated climate projections, we expect that Project CAPTURE will guide conservation, restoration, and management decision making at a national level,” says Potter. Results from this study were recently published in a special issue of the journal New Forests, co-edited by Potter, which also features an introduction by Potter and colleagues. Read more in CompassLive and in a Springer blog post on the story behind the special journal issue.

After analyzing extensive data collected on 86 tree species in the eastern United States, researchers found that most trees have been shifting their ranges westward or northward in response to temperature and precipitation changes. University and U.S. Forest Service scientists collaborated on the study, which was recently published in Science Advances. “Trees are shifting partially because of climate change, but their responses are species specific,” said Songlin Fei, a Purdue University scientist and professor who led the study. “Deciduous trees like oak and maple are primarily moving westward. Evergreens are responding in a different way. They’re moving northwards.” The researchers used Forest Service Forest Inventory and Analysis data on tree abundance documented between 1980 and 2015 for their analysis. North Carolina State University scientist Kevin Potter, a cooperator with the Eastern Threat Center, and Southern Research Station research forester Chris Oswalt were among the study collaborators. Read the Purdue University press release and news coverage on this study from Nature, the Associated Press, The Atlantic, North Carolina State University, and The Christian Science Monitor.

Land managers expect that exotic invasive plants will quickly move in following a disturbance, especially after a fire. Though exotics initially might have an edge over native plants on burned ground, this may not always be so as time goes on, according to a recently published study. Eastern Threat Center research ecologist Qinfeng Guo made this discovery after re-analyzing post-fire plant data from a southern California chaparral community that burned in November 1993 during the Old Topanga Fire. “I hypothesized that the same community may show different relationships between exotic and native plants at different points in time as vegetation regrew after the fire,” says Guo. He was correct. For two years after the fire, the number, or richness, of both native and exotic plant species increased, but exotic species made up a larger proportion of all the plant species. The richness of both exotic and native species then gradually declined, and within four years after the fire, native plant species began to dominate the larger proportion of vegetation on the site. Though this is a case study of just one fire and the resulting vegetation dynamics, “More studies like this one can help managers understand the best timing for actions that can prevent the establishment of exotic plants following fire,” says Guo. Read more in CompassLive...

How can researchers and managers ensure the survival of hemlock trees and their associated habitats and benefits to water quality? A new video from Untamed Science examines this question through interviews and footage shot around western North Carolina and eastern Tennessee where the invasive hemlock woolly adelgid has caused extensive damage to these iconic trees. Starring researchers from the Eastern Threat Center, Southern Research Station, and partners from the University of Tennessee, the video features a discussion about the scope of the problem and efforts to save Eastern and Carolina hemlock species through genetic studies and research toward rearing, testing, and releasing predator beetles--all part of a comprehensive conservation and restoration plan. The Untamed Science crew comprises scientists, educators, and filmmakers who strive to create media that make learning about science fun and easy. View the video...

Eastern Threat Center and Southern Research Station staff also collaborated with Untamed Science on an earlier video that explains the threat of invasive species and the challenges and expense of managing them.

In many situations, the adage “Dirt doesn’t hurt” is generally true. One important exception is when soil erosion and runoff deliver excessive sediment to streams, impacting water quality as well as aquatic insects, fishes, or other stream inhabitants. Forest managers use Best Management Practices (BMPs), such as the installation of strategically placed bridgemats and culverts, to safeguard stream health during forestry operations. In North Carolina, previous studies have determined the effectiveness of these structures in protecting forest streams of the mountains and coastal plain, but data from the region in between—the Piedmont—have been lacking. Eastern Threat Center biological scientist Johnny Boggs recently led a study to address this data gap. With Center researchers Ge Sun and Steve McNulty, he measured Total Suspended Sediment (TSS)—that is, sediment floating in the water column and not settled on the bottom of the streambed—at stream crossing sites in six Piedmont forests before, during, and after harvesting operations. Results, recently published in the Journal of Forestry, indicate the TSS concentrations were similar upstream and downstream of the crossing sites, providing assurance that BMPs applied at stream crossings are part of sustainable operations that can provide forest products while simultaneously protecting forest ecosystems. Read more in CompassLive...

The U.S. International Association for Landscape Ecology (US-IALE) has named Eastern Threat Center research ecologist Bill Hargrove its Distinguished Landscape Ecologist for 2017, the organization's most prestigious award. Hargrove's is the 25th such award, which recognizes scholars whose thinking, writing, and long-term scientific endeavors have shaped the field of landscape ecology. Upon accepting the award on April 18 during a ceremony at the US-IALE annual meeting held in Baltimore, MD, Hargrove told his colleagues, "This group shares a unique belief -- that the most interesting and exciting science comes from intersecting overlaps in the Venn Diagram. You've given me something that I'll never forget." Hargrove is the fourth U.S. Forest Service scientist to have received the US-IALE Distinguished Landscape Ecologist Award. He served as chair of the organizing committee for the 2016 US-IALE annual meeting held in Asheville, NC.

More than 100 western North Carolina residents, seeking to better understand the epic 2016 fall wildfire season and prepare for future fires, attended a panel discussion themed "Before We Burn Again" on April 3 in Asheville, NC. Research ecologists Steve Norman (Eastern Threat Center) and Katie Greenberg (Southern Research Station) were among the panel experts who discussed aspects of fire ecology, weather, management, and planning. "Drought is a recurring phenomenon here. We need to be ready for it,” said Norman, who has studied the occurrence of drought and its importance to fall fire seasons on federal lands in the Southern Appalachians. Though cycles of drought are not surprising, the federal land area burned in fall 2016 is: Norman found that more area burned in 2016 than in the prior 45 years combined, with human causes largely responsible for the ignitions. Blue Ridge Public Radio (BPR) covered the "Before We Burn Again" event, which was sponsored by Mountain True and the Asheville Citizen-Times.

With ramps making their annual appearances at spring festivals, farmers' markets, and restaurants, the inevitable question arises: are they at risk due to unsustainable harvesting? Skyrocketing demand for these pungent wild leeks has led Jim Chamberlain, a research forest products technologist with the Southern Research Station, to track ramp harvests destined for Southern Appalachian festivals for nearly 20 years. Since 2016, Chamberlain and Eastern Threat Center research biologist Michelle Baumflek have teamed up with the Traverse City, MI-based Institute for Sustainable Foraging to study the effects of commercial harvesting on wild ramps in Michigan. Ramps take several years to mature and reproduce, Baumflek explained to Civil Eats, a daily news source on the American food system, in an article published April 12. “If you’re holding one in your hand, the fat stem you’re holding could be seven years old," she said. Read the full Civil Eats article to learn more about the work of Chamberlain and Baumflek and others working to sustain ramp populations and the cultural traditions they inspire.

Eastern and Carolina hemlock trees in more than 400 counties across 19 states are dead, dying, or threatened by infestation of the invasive hemlock woolly adelgid. As the aphid-like pest continues to spread throughout the ranges of these economically and ecologically important trees, scientists, managers, and other specialists from North Carolina State University’s (NCSU) Camcore program are racing to collect and store seeds with support from the U.S. Forest Service. To identify priority seed collection locations across the entire range of both hemlock species, NCSU and Eastern Threat Center scientists combined information on density of seed collection to date, climate data, measures of hemlock abundance and population isolation, and four genetic diversity measures. Then, for each cell on maps depicting where eastern and Carolina hemlock occur, the combined information was compared and ranked. Their results, recently published in New Forests, include new maps that can help conservationists prioritize locations for seed collection, necessary for off-site plantings and breeding programs designed to restore hemlocks in the future. Kevin Potter, an NCSU scientist cooperating with the Eastern Threat Center, and Center research ecologist Frank Koch coauthored the study. Read more in CompassLive...

To draw people in at a public event, bring cookies! In this case, the event was the North Carolina Arbor Day celebration held at North Carolina State University on March 18. And the cookies were not edible, but crowd pleasers nonetheless. Eastern Threat Center scientists Michael Gavazzi, Qinfeng Guo, Jennifer Moore Myers, and Ge Sun and Southern Research Station (SRS) project leader Jeff Prestemon staffed an exhibit table featuring loblolly pine tree “cookies” to demonstrate how counting tree growth rings can provide an estimate of tree age and insight into growing conditions. The group also shared handouts and other products with local citizens and visitors of all ages interested in SRS research and technology that support the purpose of North Carolina’s Arbor Day observance: to beautify and conserve the state’s trees.

Healthy forests = clean water. It’s a simple idea about forests’ critical role in capturing, filtering, and delivering more than half of the water supply in the United States. But how does one know it’s true? The answer: research from the U.S. Forest Service. Southern Research Station (SRS) scientists and their predecessors have been conducting research on the connections among forest watersheds, management practices, and water quantity and quality and communicating their results for more than 75 years. The NC Source Water Collaborative recently honored SRS’s leadership and contributions to a vast body of knowledge with a Source Water Protection Award in the category of Education for “Defining and Understanding How Forests Protect Watersheds and Source Water.” Eastern Threat Center research hydrologist Ge Sun, SRS research hydrologist Pete Caldwell, and SRS project leader Jim Vose accepted the award at a ceremony on March 15 during the Water Resources Research Institute (WRRI) of the University of North Carolina System’s annual conference in Raleigh, NC. Additional scientists honored with the award include Center research ecologist Steve McNulty; SRS research ecologist Kitty Elliott and project leader Chelcy Miniat with Coweeta Hydrologic Laboratory; and SRS project leader Dave Wear with the Center for Integrated Forest Science. “The theme of the 2017 WRRI annual conference was ‘solutions through dialogue and cooperation,’” says Sun. “It’s great that North Carolina recognizes SRS contributions to water research and education through close collaboration over the years.”

By 2040, one billion tons or more of biomass could be produced each year in the United States, according to the U.S. Department of Energy’s 2016 Billion-Ton Report. Whole trees or materials left behind after logging operations, agricultural crops and crop residue, algae, and even municipal solid waste are sources of biomass that can be used for fuel, energy, heating, and chemicals. But what are the potential effects on environmental sustainability? Federal, academic, and industry scientists followed up with modeling studies examining impacts on soil, water, air quality, biodiversity, and climate and recently published their results in a Volume 2 report that can inform decision making to improve environmental outcomes around biomass production and uses. Eastern Threat Center research hydrologist Ge Sun, postdoctoral researchers Liangxia Zhang and Kai Duan, and Southern Research Station research ecologist Benjamin Rau contributed a chapter on water yield impacts. The researchers used the Water Supply Stress Index model to estimate the effects of potential forest clearcutting and thinning on seasonal and annual total water yields at the watershed and county scales. “Our study suggests that projected biomass removal levels are rather low and may not cause concerns or large benefits to water quantity and supplies at the county level, but the impacts can be significant if biomass harvesting activities are concentrated within a watershed in a county. In such a case, stormflow volume could increase, potentially causing water quality concerns,” says Sun. “Best management practices such as implementing forest riparian buffers may be effective to mitigate negative harvesting effects on stream hydrology and water quality.” Read Volume 2 of the 2016 Billion-Ton Report and related fact sheets, and stay tuned for more news and learning opportunities.

The "crop coefficient method," widely used in agriculture to estimate how much water crops will need, describes the difference between the actual amount of water lost to the atmosphere and the amount of water that could be lost if there was unlimited water available. Eastern Threat Center scientists and colleagues working together through the U.S.-China Carbon Consortium (USCCC) are among the first to apply it to forests. Results from a recently published study, coauthored by Ge Sun and Steve McNulty, could help land managers deal with prolonged or severe drought conditions or evaluate trade-offs between managing for water supply or carbon storage across seven forest cover types—including broadleaf, evergreen, and mixed forests. “The study offers practical ways for estimating the seasonal dynamics of ecosystem water use and stress,” says Sun. Read more in CompassLive...

Over the past 40 years since the passage of the Clean Air Act, air pollution from automobiles, factories, and power plants has substantially decreased, leading to better human and environmental health. But air pollution and its impacts on people and ecosystems remain a concern amid growing demands for transportation, energy, and manufactured goods. University and U.S. Forest Service researchers believe air pollution could also be a hidden driver of important changes in the nation’s watersheds following a recent study published in the January issue of the journal Climatic Change. Kai Duan, a North Carolina State University postdoctoral researcher working with the Eastern Threat Center and the study’s lead author, worked with a team of researchers to combine a series of models, including a global climate model, a regional climate model, and the Water Supply Stress Index (WaSSI) model. The scientists ran the models with and without accounting for the impacts of air pollution on climate in order to assess the individual and combined impacts of climate change and air pollution on water availability and ecosystem productivity. Study results indicate that, while aerosols in air pollution could partially offset higher temperatures, greenhouse gases will continue to drive higher temperatures and associated increases in ecosystem water use. Read more in CompassLive...

Pictured: Reds, oranges, and yellows show potential decreases in water supplies by the middle of the 21st century based on stable (a. and b.) and rising (c. and d.) atmospheric concentrations of greenhouse gases. Maps b. and d. take air pollution into account; maps a. and c. do not. Click to enlarge.

The U.S. Forest Service recently sponsored a two-day workshop in Atlanta, GA, to identify and assess drought adaptation strategies for national forests across the Southeast. In attendance were more than 30 regional experts from the Eastern Threat Center-hosted USDA Southeast Regional Climate Hub (SERCH); the Forest Service Southern Research Station, Southern Region, and Office of Sustainability and Climate Change; and state and federal climate offices who discussed how drought impacts the many benefits derived from forest lands, including species habitat and survival, clean water supply, and recreational activities. Attendees formed working groups to examine management opportunities for improving resilience when coping with drought in the Southeast and to develop a white paper to inform regional and national drought adaptation policies. "This was a well-attended and important workshop, especially when we consider the frequent nature and wide-ranging impacts of droughts across the region and potential for increased drought severity and occurrence in the future," says acting SERCH Coordinator Michael Gavazzi. "The workshop was an important step toward providing land managers with the tools, strategies, and information they’ll need to successfully manage ecosystems for drought adaptation."

Research hydrologist Ge Sun and biological scientist Michael Gavazzi are among the recipients of the 2016 Southern Research Station (SRS) Director's awards. Sun, who has co-authored about 220 papers since his U.S. Forest Service career began in 1997, received the Distinguished Scientist Award "for sustained productivity and leadership in forest hydrology research including the development and application of hydrological models and tools for global natural resource management under a changing environment." Gavazzi, who has served as the Collateral Duty Safety Officer at the Center's Raleigh office for 15 years, received the Safety and Occupational Health Award "in recognition of continued excellence in cultivating a safe and healthful work environment where all employees feel enabled to openly discuss issues and expect timely resolution to their concerns." SRS Director Rob Doudrick will honor Sun, Gavazzi, and recipients of five other awards at a reception in April.

With so many challenges and options to consider, forest managers wondering, “What is the right way to respond to current and future climate change?” may need to reframe the question. “There is no single ‘right’ way to respond to climate change,” explains the narrator in a new U.S. Forest Service Climate Change Resource Center (CCRC) education module, “and many different actions will be needed to address the challenges.” The module, “Responses to Climate Change: What You Need to Know,” provides a brief overview of resistance, resilience, and transition—approaches that can help forests adapt to climate change—and ways to incorporate these ideas into natural resource planning and activities. Interactive features allow users to control their learning experience, with plenty of opportunities to explore additional information and examples of managers adapting to climate change in a variety of forests. The main material is followed by a regionally-specific activity: creation of an adaptation plan based on real-world examples. Read more in CompassLive...