Posted: April 3, 2024

Across the United States, forests face unprecedented threats, and scientists in Penn State's College of Agricultural Sciences are conducting novel and complex research to conserve them.

Photo: Penn State

Photo: Penn State

In Pennsylvania — the only state named after its forests and home to the country's most abundant hardwood forest, sustainably managed over the last century — researchers are focusing on helping foresters overcome the modern challenges they face.

U.S. forests are threatened by invasive species and pests disrupting native ecosystems, deforestation due to urbanization and agricultural expansion, and changing weather patterns. Although forests, in general, are resilient ecosystems, changes — particularly related to climate change — may be happening faster than forests in some regions can adapt, resulting in the decline of desired tree species and the ascendancy of unwanted tree species, domination by habitat-degrading invasive plants, and the emergence of devastating insect populations and diseases.

"Our scientists are conducting vital studies related to forest health, resiliency and management in the woodlands of Pennsylvania and far beyond," said Blair Siegfried, associate dean for research and graduate education in the college and director of the Pennsylvania Agricultural Experiment Station. "They are working to preserve genetic diversity in tree populations to protect and restore vulnerable species in the face of invasive pests and plants and climate change."

Researchers are employing the latest approaches in genomics and using innovative tools such as machine learning, satellite imagery and drones to understand and conserve our forests, Siegfried added. "We are focused on anticipating and mitigating unwanted forest changes resulting from a legacy of damaging anthropogenic, or human-caused, influences."

A student in the research group of Tong Qiu, assistant professor in the Department of Ecosystem Science and Management, operates a drone. Crewless aerial vehicles are used to collect forest measurements and observations.
A student in the research group of Tong Qiu, assistant professor in the Department of Ecosystem Science and Management, operates a drone. Crewless aerial vehicles are used to collect forest measurements and observations.

Carbon concerns in Penn's Woods

With nearly 17 million acres of forestland, Pennsylvania leads the nation in the volume of hardwood forest and hardwood lumber created and exported. According to the Pennsylvania Department of Agriculture, the forest products industry comprises more than 2,000 companies that employ more than 90,000 Pennsylvanians. Each year, the industry harvests about 1 billion board feet of lumber. With an annual direct impact of $21.8 billion on the state's economy, the industry is looking to Penn State researchers to provide solutions to multiple challenges.

Among those challenges, explained Ken Kane, past president and owner of Generations Forestry Inc. in Kane, are difficulty regenerating desired species such as black cherry, finding markets for low-grade forest material, and a dearth of science-driven guidance for managing forests to maximize carbon storage and timber harvests. This latter concern is generating considerable debate both within and outside the industry.

"There needs to be more research conducted on the carbon sequestration of a managed forest," said Kane, who is chairman of the board of the Pennsylvania Forest Products Association. "We would like to know what age class of a forest consumes the most carbon and produces the most oxygen because that's the optimum for carbon sequestration. That's the stage where we'd like to keep our forest."

Pennsylvania's forests are key contributors to carbon sequestration, the natural process of capturing and storing atmospheric carbon dioxide in the trees, agreed Margot Kaye, professor of forest ecology and interim head of the Department of Ecosystem Science and Management. She added that the Keystone State's vast woodlands are an important mitigation resource for a warming world.

Students in the lab of Margot Kaye, professor of forest ecology, take tree measurements to study carbon capture and sequestration in Stone Valley.
Students in the lab of Margot Kaye, professor of forest ecology, take tree measurements to study carbon capture and sequestration in Stone Valley.

"Forest management is the most effective tool to ensure continued forest resilience and productivity, but few examples exist that demonstrate how silviculture accelerates carbon uptake while simultaneously actively managing for climate resilience," she said.

Funded by a grant from the U.S. Department of Agriculture, Kaye and her students are exploring forest management protocols that promote carbon storage in mature trees while ensuring the regeneration of climate-adapted tree species. She suggested that the results of this study can be applied worldwide to temperate deciduous forests experiencing climate change pressures. The researchers will combine silvicultural treatments focused on carbon and climate adaptation with analyses of these treatments' carbon and economic budgets.

The researchers have installed experimental treatments in Penn State's Stone Valley Experimental Forest to test forest management strategies that may improve forest carbon sequestration and climate adaptation. The team designed demonstration forests that have been thinned to promote carbon sequestration and planted with seedlings of tree species expected to thrive under future climate scenarios.

Undergraduate Evan Hackett builds seed traps in Penn State's Stone Valley Experimental Forest.
Undergraduate Evan Hackett builds seed traps in Penn State's Stone Valley Experimental Forest.

The scientists will analyze the carbon lifecycle impacts of forest carbon and climate adaptation management protocols, calculating a forest carbon budget that identifies the effect of thinning treatments on carbon sequestration. This budget will guide forest carbon management plans and inform carbon-credit programs.

"We will analyze the ecological and financial costs and benefits of forest carbon and climate adaptation management," Kaye said. "We'll produce a budget for carbon and climate adaptation management protocols that can be used by forest landowners who are considering novel combinations of silvicultural treatments that would promote climate mitigation and adaptation on their land."

According to its executive director, Matt Gabler, the Pennsylvania Forest Products Association is especially interested in findings from Kaye's work that will quantify the carbon benefits of forest management. The organization and its members seek guidance showing how Pennsylvania forests can store as much carbon as possible while yielding acceptable amounts of timber.

"We hope Penn State researchers can offer quantifications for how our industry can provide both economic and environmental solutions for Pennsylvania forests to provide carbon sequestration while continuing to feed the entire forest product supply chain," Gabler said. "From a respected academic perspective, it would be helpful to see calculations showing how harvesting mature trees and growing new ones — and using wood products in enduring ways — affects the carbon balance of the forest."

Forest carbon and climate education

Melissa Kreye, assistant professor of forest resources management, and Calvin Norman, assistant teaching professor of forestry, are working to provide landowners with education in climate-smart forestry. Their goal is to support landowners who are considering which carbon assistance programs are a good fit for their woodlands and management objectives.

"Helping private forest owners make smart decisions about climate-smart forestry is good for the climate and helps the forest economy grow by protecting forest health and opening new viable markets," Kreye said.

Kreye's and Norman's educational initiative is a model of interdisciplinary collaboration. She is an economist and social scientist with experience in and understanding of ecosystem services markets, their structure and the people who operate them. He is a forester with expertise in forest management and forest products and experience interacting with small-scale private landowners.

Kreye and Norman are the first and only extension team working at the national level with nonindustrial landowners and private lands stakeholders. They have forged relationships within Penn State and well beyond to connect with extension and researchers at other universities, the U.S. Forest Service, market makers, forest industry stakeholders and landowners.

The two faculty members are leading an initiative that includes 13 land-grant universities and three USDA Climate Hubs. In 2022, they received a $1.5 million grant from USDA's National Institute of Food and Agriculture to support the education of landowners, extension educators and other stakeholders in forest carbon, carbon markets and the carbon economy across the Midwest, Southeast and Northeast.

Space age forest management in the Keystone State

From carbon in the woods to objects in orbit, a research team led by an ecologist in the college is using a $1 million grant from NASA to integrate satellite data into predictive modeling, with an eye toward anticipating change in recruitment — the process by which new trees emerge — within Eastern forests.

In partnership with the Pennsylvania Department of Conservation and Natural Resources, researchers will use data generated by NASA Earth-monitoring satellites to inform the department's decisions on seeding and planting and help cope with the migration of tree species, habitat and wildlife. Tong Qiu, assistant professor in the Department of Ecosystem Science and Management, will lead the project.

DCNR's Bureau of Forests oversees 2.2 million acres of woodlands, representing one of the largest expanses of public wildland in the eastern U.S. The bureau's multifaceted mission, Qiu noted, includes protecting forest ecosystems from threats such as wildfire, pests and disease, and sustainably managing timber to meet society's needs, while providing wildlife habitat and supporting recreational activity. In addition, the bureau must maintain biodiversity to promote forest resilience.

The bureau needs to address several challenges to accomplish these goals, Qiu explained, and one primary concern is ensuring successful and timely forest regeneration following harvests and other disturbances such as pest outbreaks and wildfires.

Also, deer management in public forests could be improved by satellite-provided data. Qiu said that deer are a key factor in diminishing forest regeneration in Pennsylvania. Still, the cost of installing deer fencing is too high, at $15 per foot, to be a reasonable blanket solution.

"Predictions of deer-browsing impacts will guide limited budget allocations to prioritize areas in need of deer fencing and help DCNR submit proposals for supplemental hunting permits to reduce deer pressure on seedling survival," Qiu said.

Penn State Extension offers forest education

Penn State Extension's forest management team works with the U.S. Forest Service, DCNR, the Pennsylvania Forest Products Association, the Pennsylvania Department of Agriculture and other stakeholders to offer education and training about woodland stewardship, best management practices for forest landowners, forest ecosystems, wildlife, water quality, tree identification and measurement, and legacy planning.

The array of articles, webinars and in-person trainings related to forests offered by Penn State Extension is extensive, according to Calvin Norman, who also is an extension forester. He said the public's and the industry's appetite for these offerings is considerable.

"For example, extension educators Scott Weickert and Mike Powell do lumber-grading workshops, and the industry loves those because they cannot hire enough qualified lumber graders," Norman said. "We do at least four important and unique trainings annually, and we bring in folks from the National Lumber Grading Association."

Recently, Norman took undergraduate students in one of his forest measurements classes to a sawmill. The sawmill operator saw that the students were taking log measurements and were discussing how log measurements are turned into lumber measurement. The sawmill operator tried to hire the students on the spot.

"I was like, 'No, no, these students have to finish their degrees,'" Norman said with a chuckle. "It shows how needed and important the training is, and no one else offers it except Penn State Extension. You know, a sawmill cannot pay for this training."

Fostering forest stewardship

To promote forest stewardship practices aimed at sustaining healthy and resilient private forests that contribute to the social, ecological and economic well-being of society, the college created the James C. Finley Center for Private Forests. It offers applied research, education and outreach to students, forest landowners, the forest products industry, loggers, conservation districts, agencies, land trusts, nongovernmental organizations, and the public in Pennsylvania and beyond.

Working at the intersection of people and forests, the center advances research-based insights to inspire and cultivate stewardship of private forests by providing resources to woodland owners. These resources include conferences, webinars, newsletters and technical assistance on subjects such as creating riparian buffers, legacy planning and achieving adequate forest regeneration.

The center's programs are aimed at inspiring a growing community of private forest landowners to adopt stewardship values and practices on their land by fostering a shared vision and understanding of stewardship among private forest landowners, professionals and academic faculty.

More than trees in Pennsylvania forests

Along with trees, Pennsylvania forests are home to nontimber forest products, often referred to as NTFPs. Eric Burkhart, associate teaching professor of ecosystem science and management, has researched the status of these often undervalued plants, assessing the sustainability of the resources from which they originate.

In addition to focusing on the long-term welfare of the plant populations, he investigates the economic stability of the often secretive people involved in harvesting and selling these plants in Pennsylvania and the Appalachian region. Information and knowledge needed to determine if collection activities are socially, economically and ecologically sustainable, he explains, is lacking.

Burkhart, director of the Appalachian Botany and Ethnobotany Program at Penn State's Shaver's Creek Environmental Center, and his students continue to research questions relating to Appalachian forest plant botany, ethnobotany, ecology, phytochemistry, horticulture and agroforestry.

Partnering with a variety of faculty and lab groups across the university, including in food science, plant biology, veterinary and biomedical sciences, anthropology, and ecology, their research focuses on the following culturally and economically significant eastern North American forest plants: American ginseng, goldenseal, ramps/wild leek, ghost pipe, prickly ash and wild mushrooms.

Burkhart's research has been instrumental in tracking the growing trend of ginseng forest farming in Pennsylvania and the East — often using seeds imported from outside the region. In his eight-year study, he sought to determine how many people are planting the valuable forest herb — and whether what they sell as "wild" is really wild. The research aimed to more accurately inform efforts to conserve and promote forest farming of the species.

"NTFPs are, perhaps, an often overlooked aspect of forest conservation, but they should be included in any serious conversation around conserving and protecting the woodland ecosystem," he said.

In the next few years, Burkhart's research group in Pennsylvania will study ghost pipe and prickly ash for agroforestry crop development and human health, evaluate factors driving the chemical quality of ramps, and serve as botanical field crew educators and a technical resource for the Penn State Deer-Forest Study, funded by the Pennsylvania Game Commission.

Out of the ashes

The decimation of ash trees by the emerald ash borer and the continued expansion of the invasive beetle pose an imminent threat to forest-based ecosystems and economies across the U.S. Consequently, according to Jill Hamilton, associate professor and Joseph E. Ibberson Chair in Silviculture Research, there is a need to pair proactive conservation of germplasm for threatened species with the development of genomic resources to inform future breeding programs for ash. Germplasm is genetic material such as seeds, tissues and DNA sequences maintained for plant breeding.

"The U.S. Forest Service and collaborating agencies have made substantial efforts to identify lingering ash — ash trees that appear to be somewhat resistant to the emerald ash borer — and initiated a breeding program in which lingering ash crosses are being bred for resistance," she said. "This program requires a long-term investment, but progress is being made, and I am guardedly optimistic about the future of ash."

While there is growing emphasis on the importance of genetics in conservation, and advancements are being made in developing whole-genome-sequence resources for diverse ash species, she said that a substantial gap remains in understanding differences within ash species and how the environment has influenced the evolution of genetic differences within those species. Her research is aimed at bridging that gap.

Funded by grants from the U.S. Department of Agriculture and the Nature Conservancy, Hamilton and her students are in the process of genomic screening of seed and living collections to quantify genetic variation within and across ash populations. They are starting with a common garden of ash trees planted in 1974 on Penn State's University Park campus by Kim Steiner, professor emeritus of forest biology.

Those trees, grown from seed collected across North America, are all dead now, victims of the emerald ash borer. But some persisted much longer than others and many have resprouted, allowing the researchers to take tissue samples for genetic analysis.

In addition to leveraging Steiner's trial, Hamilton's research group also is establishing new trials. Focusing on black ash, the team is working with partners across the range of black ash, including Canadian and U.S. collaborators.

"Similar to what Kim Steiner did in the 1970s, we want to understand rangewide variation," she said. "We have worked alongside partners in Maine to ensure seed is maintained in the bank today to be used for restoration into the future. If we get to the point where we need to do a lot of ash restoration in the forests, we think we can use our record of today's ash to help inform that restoration in the future."

Climate-smart seed sourcing

In Pennsylvania, foresters rarely need to supplement natural seeding by planting trees. Still, increasingly in other regions of the U.S., such as the West, foresters must supplement natural seeding to achieve needed levels of recruitment and ensure climate-adapted forests, according to Laura Leites, research professor of quantitative forest ecology.

She said many forests in Pennsylvania and beyond have been degraded due to insect infestations, diseases, invasive plants, climate change and high grading (harvesting methods that remove only the most valuable timber and leave the rest in the woods). These challenges threaten the health and longevity of forests around the world.

Degraded forests generally are characterized by low tree species diversity, few vigorous seed trees and low stocking levels. In these cases, Leites explained, tree plantings to supplement natural regeneration likely will be needed to achieve the desired species composition and maintain forest resilience and productivity under a changing climate. In addition, challenges in regenerating certain species, such as oaks, also lead to increased planting to maintain existing forest compositions.

Laura Leites, research professor of quantitative forest ecology, conducts studies on climate-smart seed sourcing.
Laura Leites, research professor of quantitative forest ecology, conducts studies on climate-smart seed sourcing.

"Planting of seedlings to restore, reforest and supplement natural regeneration is likely to continue to increase in importance in our region as a management strategy to ensure forest health and productivity now and in the future," she said. "As any experienced forester or landowner will attest, choosing the appropriate seed sources is extremely important. A seed source genetically well adapted to the planting site's climate and environmental conditions is critical to ensure planting success and future forest productivity."

At the federal level, there's a big push to develop knowledge to support reforestation and restoration efforts, Leites pointed out, and her lab is involved in four research projects related to understanding how tree species adapt to climate. Awards from the U.S. Forest Service underwrite two, and a USDA grant supports another.

László Kulcsár, interim dean of the college, lauded the collective efforts of faculty, students and extension educators to conserve invaluable forest resources.

"Our college's scientists are resolute in their commitment to safeguarding woodlands, serving as vigilant custodians of biodiversity," he said. "Acknowledging the intricate interdependence of forest health, wildlife vibrancy and human well-being, they articulate a narrative that secures the lasting legacy of our forests."

By Jeff Mullhollem

Seeds of Change

Genetic analysis helps reveal how ash trees respond to threats

At the Louis W. Schatz Center for Tree Molecular Genetics at Penn State, researchers have been using genetic and microbial analysis to understand evolutionary changes in ecosystems for the better part of two decades.

"Broadly speaking, we're interested in the mechanisms that contribute to adaptation," said Jill Hamilton, associate professor and director of the center. "We want to understand the persistence of species in both natural and managed plant systems, not only in current environmental conditions, but looking forward to future environmental conditions."

One current project spans the entire continental United States. The team is using genetic analysis to gauge how well ash trees respond to threats from climate change and the emerald ash borer. The invasive beetle, native to northeastern Asia, feeds on all ash species and has wiped out large swaths of the trees across the U.S.

Kyra LoPiccolo, doctoral candidate in plant biology who works in Hamilton's lab, spent the past summer road-tripping 11,000 miles across the country collecting seeds and genetic samples from ash trees.

She and her research colleagues will map the distribution of genetic variation among ash trees in the U.S. with the hopes of understanding enough about their evolution and adaptation to be able to successfully restore the species to areas where it is most at risk.

As LoPiccolo canvassed the nation searching for ash leaf samples to sequence, she and her fellow researchers also collected black ash seed — part of another project that has roots dating back thousands of years.

"It's a race against time because when the mature trees are gone, it's going to be years before the trees are producing seed again," LoPiccolo said.

Black ash has ecological and cultural significance, she explained. It is the only hardwood tree that can thrive in boggy environments, such as swamps. Its root system essentially holds together the entire ecosystem. Without black ash trees, the habitat would convert from swamp to open, marshy wetlands, she said.

The Wabanaki people, who have lived in the land now called Maine for some 12,000 years, link the story of their creation to black ash. In the creation story, the cultural hero Gluskabe created the people by shooting an arrow into the trunk of a black ash tree. The people came into the world through the hole made by the arrow.

And once they arrived, Gluskabe taught them how to weave the tree's straight-grained wood into baskets.

Today, members of the four Wabanaki nations — the Maliseet, Micmac, Penobscot and Passamaquoddy people — continue to use black ash as the principal building material for baskets, which are used and sold as tribal art. Black ash remains a vital part of Wabanaki cultural identity and the local economy, LoPiccolo explained.

That's why LoPiccolo and a team of genetic researchers from Penn State have partnered with John Daigle, a social scientist and professor of forest recreation management at the University of Maine, to work with indigenous communities to better understand the cultural and social significance of the black ash tree. Daigle, who is a member of the Penobscot Indian Nation, studies the emerald ash borer and its impact on trees and Wabanaki tribes across New England.

"I think it's a beautiful collaboration," LoPiccolo said. "If in the end we are able to support a large-scale restoration of the species, it's vital that indigenous communities are involved from the beginning so that any solution integrates all perspectives."

At the college's Mendels Way greenhouse in State College, LoPiccolo and her team are working to germinate 22,000 black ash seeds with the goal of one day replanting them in common gardens throughout the Northeast.

"It's very ambitious," LoPiccolo said. "The seeds are currently in the vernalization stage, and we're going to plant them in the spring. We hope to have greenhouses full of baby black ash trees that we can use to understand genetic differences across the range of black ash and, most importantly, that we can use to lay a foundation for restoration into the future."

— Adrienne Berard