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May 2014

In the lexicon of forestry, “disturbance” means something more serious than the word means in common usage. Disturbances are events that remove or kill trees and other plants, and they come in many forms. Tornados and straight-line winds are forest disturbances, as is timber harvest. Whether their effect is rapid or slow, invasive plants and insects are disturbances that alter entire ecosystems. Disease pathogens can virtually eliminate a tree species from the landscape (think Dutch elm disease and American chestnut blight).   

Scientists with the Northern Research Station study disturbance to better understand how they affect the landscape change over time. Our research aims to lessen the impact or mitigate impact to forests from disturbance. This month, we feature a scientist, research project, product and partnership with roots in the disturbance.

Environmental Education Links

May 3, 2014 is National Wildfire Community Preparedness Day. Check out the National Fire Protection Association’s teaching tools at:

Their Kid’s corner provides links to wildland fire editions of the Natural Inquirer, day camp activities for middle school students, a full fire curriculum for high school-age students, and more.


ClimateChangeLIVE is a year-long distance learning program designed to provide credible, science-based climate change education resources in an engaging way that encourages students to develop a stewardship ethic wherever they live. Check out our resources at

Featured Scientist

Erika Svendsen

Erika SvendsenErika Svendsen has great regard for the many ways in which researchers have measured the quantifiable benefits of trees – benefits like reducing energy costs and intercepting storm water – but she is more intrigued by the psycho-social benefits.

A research social scientist and a co-director of the New York Urban Field Station, Svendsen’s work  explores the ways that people use nature to foster individual and community reliance. The Field Station is a collaboration between the U.S. Forest Service and the New York City Parks and Recreation Department and presents myriad opportunities for exploring the full spectrum of nature’s benefits in the city.

Shortly after 9/11, Svendsen began investigating how stewardship of trees and open space was used to build resilience in New York City and throughout the United States. Today she is part of “Landscapes of Resilience,” a multi-disciplinary research team studying when, where, how and why residents use greening activities as a mechanism for recovery and restoration. “Landscapes of Resilience” focuses on Joplin, Mo., which was devastated by a tornado in 2011, and neighborhoods within New York City that were damaged by Superstorm Sandy in 2013.

For Svendsen, nature is a means of improving people’s lives. “Nature can be a catalyst in harnessing the capacity of people to do good things for themselves and others,” she said.

Find out more on Erika Svendsen's biography page >>

Featured Product

Central Hardwoods Vulnerability Assessment

Closed central hardwood forest.Scientists with the Northern Research Station and the Northern Institute of Applied Climate Science (NIACS) are bringing climate change home for forest managers in the Central Hardwoods Region.

More than 30 scientists and forest managers contributed to an assessment of the Central Hardwoods Region forests’ vulnerability to climate change. The assessment, “Central Hardwoods Ecosystem Vulnerability Assessment and Synthesis: A Report from the Central Hardwoods Climate Change Response Framework Project,” describes climate change that has occurred over the past century, expected changes to the region’s climate over the next 100 years, and implications for forest management.

The vulnerability assessment gives forest managers information that they can use today to improve the health of forests and their ability to adapt to a changing climate. “Our intent was to create a climate change resource that will be relevant to people who work, study, recreate, manage and care about the ecosystems in the Central Hardwoods Region,” said Leslie Brandt, a climate change specialist with the Station and the lead author of the Central Hardwoods vulnerability assessment.

More information >>

Featured Research

Invasive Plants

Foresters hike through dense forest cover.Prescribed burning and tree harvesting are key tools in promoting the health and sustainability of Eastern forests. Unfortunately, these disturbances may also lead to invasion by exotic plants.  How can we promote healthy forest regeneration without also promoting invasions? Research botanist Cindy Huebner has been investigating that question in a 5-year project that ends this year.

Huebner and her team evaluated germination, survival, and growth of three invasive plant species (tree-of-heaven, garlic mustard and Japanese stiltgrass) that are typically found in disturbed forests. They studied these species under five management regimes (control or undisturbed forests, single burns, repeat burns, selection harvests or thinnings, and heavy shelterwood harvests) along regional and local moisture gradients at 56 field sites in West Virginia, Ohio, and Virginia.

One surprising research result is that all three of the invasive plant species studied survive equally well in the five management regimes studied, Huebner said. The invasive species did germinate and grow more in the higher light sites, especially any sites with light levels greater than 10 percent of full sunlight, such as the shelterwood harvests. However, harvested sites with more cover of native species in the understory showed lower germination and growth of the invasive species, indicating that healthier forest sites with ample native species growth may be less likely to be invaded.

The team is working on modeling the cost of potential invasion of different forest management scenarios, so that forest managers and owners may be more willing to harvest at lower light levels once they factor in the probable cost of invasion.

More Information >>

Featured Partnership

Pagami Creek

Partners at Pagami Creek.

A partnership among the Northern Research Station, Superior National Forest, the University of Wisconsin – Madison, Iowa State University, the University of Minnesota, Michigan State University, and North Dakota State University is taking advantage of a unique research lab that was created over the course of a few weeks starting on Aug. 18, 2011.

On that day, lightning ignited the Pagami Creek Fire in the Boundary Waters Canoe Area Wilderness (BWCAW), about 14 miles east of Ely, Minn. The largest fire in the BWCAW since 1894, the Pagami Creek Fire burned more than 38,000 hectares. It also created a unique opportunity to study large-scale natural disturbance, which can significantly change forest species composition and structure, soil properties and carbon, nitrogen and mercury emissions at a landscape scale. 

Based on the area of the fire and comparisons to unburned controls, scientists estimate that more than 500,000 Mg of carbon, nearly 5,000 Mg of nitrogen and over 250 kg of mercury were emitted to the atmosphere as a result of the Pagami Creek Fire.  For comparison, that amount of carbon is similar to the amount of carbon that 52,000 sport utility vehicles emit into the atmosphere every year. The amount of nitrogen is similar to the amount of nitrogen used in fertilization of 31,000 ha of corn.  The mercury emissions are comparable to about 18 percent of the 2010 annual emissions for the state of Minnesota.

What converted the Pagami Creek Fire from scorched earth to research opportunity was the wealth of highly detailed spatial data on pre-fire forest composition, structure, and disturbance history.  This included unique data such as NASA hyperspectral imagery, forest plot and biogeochemical cycling data, and spruce budworm disturbance assessments. The partnership’s research will facilitate a more complete examination of spatial feedbacks underlying forest landscape structure, fire disturbance, and future patterns of ecosystem recovery.

More Information >>