As you zip up your boots and wrap a scarf around your neck, you might be tempted to grumble about the cold. For forests, however, a few months in the freezer is not a bad thing. This month, our web features introduce an ecologist who has become inured to most any challenge Nature presents; research demonstrating how cold weather benefits forest ecosystems; and a partnership that is helping disease-tolerant American elm warm up to colder regions.
Become a Junior Snow Ranger with these activities from the USDA Forest Service.
Sjana Schanning has been working remotely for 20 years, and for Schanning that means something very different from telework. As an ecologist with the USDA Forest Service’s Forest Inventory and Analysis (FIA) Program, Schanning’s commute involves hiking, or occasionally backpacking to an inventory plot, sometimes in deep snow, sometimes through muddy swamps, but rarely on a dry, pleasant trail.
Once she reaches a plot, Schanning spends anywhere from 3-6 hours taking tree measurements, identifying woody vegetation, and classifying stands according to forest type, age, site index and other land use classes. Deep in the woods, she is often beset by black flies and mosquitos as she works. “I end up in a lot of places that I wouldn’t go for fun,” Schanning said.
Schanning is one of the people who collects data from approximately 7,500 randomly selected research sites within the 24 Midwestern and Northeastern states that make up the Northern Research Station’s FIA program area. Her work contributes to a national inventory that allows FIA to monitor the productivity and health of forests, detect changes in many attributes of forests, and recognize trends in forest conditions. The data is used for studies ranging from wildland fire danger and wildlife habitat to carbon sequestration and climate change.
In recent years, Schanning has been part of a new frontier for FIA, the inventory of urban forests. Schanning has contributed to the development of Urban FIA protocols and field guides that identify exactly how a crew collects data. “Urban forests play a smaller role in benefits like carbon sequestration than natural forests, but what they do has a more direct impact on many people, making them an important part of the urban landscape,” she said.
The daughter of a natural resource engineer, Schanning came by her interest in data naturally. As part of a family that biked, hiked and canoed when she was growing up in New York, she also forged a strong affinity for nature. When Schanning felt a need to be recharged, her response was to go even deeper into nature for inspiration. She devoted 3 years to planning and preparing before setting out to kayak the entire perimeter of Lake Superior, a 1,500-mile trip. Aside from her husband joining her at designated points to visit and deliver food she had packed, Schanning paddled most of the 83-day sojourn alone.
“It is easy to forget why you are really out there doing what you do,” Schanning said. “That was a good way to reconnect with nature.”
More about Sjana Schanning >>
Changing Climate and Fewer "Snow Days" in the Northeast
Record-setting wildfire and hurricane seasons are often attributed to changing climate conditions, which might suggest that summer is when we will most notice climate change. But a changing climate also has significant effects on winter seasons in the Northeast and southeastern Canada. In a recent study, a group of scientists took advantage of 100 years of meteorological observations across the northern forest region to learn about how winters have changed over time and how the changes have impacted ecosystems and communities.
“Cold temperatures and snow have important roles in healthy forest ecosystem functioning, but we still lack a comprehensive understanding of how winter climate may impact hydrological and biogeochemical processes and the social and economic activities they support,” says John Campbell, a research ecologist with the Northern Research Station and study co-author.
In analyzing the 100 years of data, scientists observed a general pattern of warming winter temperatures and reduced snow cover manifested as increased numbers of “Thaw Days” and “Bare Ground Days” and decreasing numbers of “Frost Days” and “Snow Covered Days.” These trends have both positive and negative implications for ecosystems.
Positive outcomes for tree health include reduction in fine root mortality and nutrient loss associated with winter frost. However, without lower temperatures, insect pests might proliferate during the growing season. Increased unfrozen, muddy winter conditions may slow down logging operations, especially in wet areas, hampering a critical tool in managing for the health and sustainability of a forest. Warmer winter temperatures and less snow also have implications for recreation, tourism and cultural practices.
“Results of this study have reconfirmed that Northern forest winters are losing the cold, snowy conditions upon which ecosystems and people rely,” said Campbell. “Loss of cold and snow may require fundamental changes of the socioecological system of northern forests.”
Breeding Cold-Tolerant Elms to Restore Ecosystems
American elm (Ulmus americana) was once widely distributed and common throughout the eastern United States, being a component of several major North American forest cover types and representing ‘Main Street America’ as a primary tree on many boulevards and avenues. Then, in the 1930s, the Dutch Elm Disease (DED) fungal pathogens, Ophiostoma ulmi and O. novo-ulmi, were introduced into the United States. This resulted in the destruction of millions of American elms across the country, significantly altering natural forest systems and boulevards alike. Today, few mature elm trees survive in America’s forests.
Northern Research Station scientists in partnership with the Chippewa National Forest (CNF) are identifying and breeding DED-tolerant varieties of American elm. Scientists are interested in restoring American elms in places where it once stood while also exploring the potential for DED-resistant elms to be used in the restoration of ash ecosystems in response to the threat of Emerald Ash Borer (EAB).
Travis Jones, a CNF silviculturist, believes elm trees may be used to offset the impacts of EAB in black ash wetlands. “Ash and elms both grow well in wetland areas,” Jones said. “To compensate for ash mortality, we are looking at planting DED-tolerant elms – we just need to make sure the elms we plant can handle our cold winters.”
Restoration of American elm requires trees that can survive DED and are adapted to a variety of growing conditions. “While scientists have been breeding DED-tolerant elm trees for many years, we are now understanding that disease resistance can vary depending on environmental conditions, such as extreme cold.” said Northern Research Station scientist Charlie Flower. “We are working to identify and breed American elms that are DED-resistant, while also ensuring trees can survive a range of winter conditions.”
The interactions between genetic attributes (disease resistance) and environmental conditions (cold tolerance) represents a challenge for plant breeding programs and land managers seeking to include elms in silvicultural prescriptions. Untangling the genetic and environmental variability in individual trees will provide land managers greater certainty in using American elm in restoration efforts.
“Propagating DED- and cold-tolerant elms with the CNF gives us a one-two punch,” Flower said. “We are producing trees that can be used to restore elms across their former range as well as developing a novel approach to replacing ash trees in wetland systems.”
More information on Cold Tolerance of American Elm >>