Change and Resilience in Boreal Forests in Northern Minnesota

PROJECT OVERVIEW
Boreal forests of spruce, fir, paper birch, aspen, and jack pine cover more than two million acres of northern Minnesota, including the Boundary Waters Canoe Area Wilderness. These forests are near the southern edge of their geographic range. With a warmer climate the health and productivity of these forests may be jeopardized by increased stresses such as heat, drought, fires, storms, and insect pests resulting in a much different forest ecosystem for northern Minnesota in the future. Scientists at the University of Minnesota's Department of Forest Resources are using this appropriation to evaluate how these forests are poised to respond to these changes and obtain the necessary data to guide forest management and planning efforts, such as determining practices that will help fend off threats from invasive species.

OVERALL PROJECT OUTCOME AND RESULTS
This project addressed the stewardship of forests in Minnesota's most renowned and iconic natural area - the Boundary Waters Canoe Area Wilderness (BWCAW) - under a changing climate. Forests of the BWCAW are at the very southern edge of the boreal forest biome (cold adapted forests of spruce, fir, pine, birch and aspen), with temperate forest species (primarily red maple) from the south, as well as exotic invasive species poised to invade in a warming climate. The purpose of the study was to map these species and temperatures across the BWCAW to gain insight into change that may occur in the BWCAW as the climate warms. For this purpose, PhD student David Chaffin placed 106 temperature sensors across the landscape, which measured temperature hourly for two years, accompanied by 106 plots on which all tree species abundances were measured. Also, 100 transects totaling nearly 16 miles in length were placed across the landscape to sample for the presence of temperate tree species and invasive species. Results show that European earthworms are a common invasive group of species; about 70%, and 33% of the forests within the BWCAW are at minimal and high stages of invasion, respectively. Earthworm invasion is related to distances from campsites, portage trails and motorized lakes, but not to temperature. Summer (June, July and August) daily maximum temperatures show a west (warm) to east (cool) gradient of about 12-13 degrees F across the BWCAW. Red maple abundance was positively related to summer temperature, being highest in the west. The main synthesis from all of the data collected during the project is that boreal conifers like black spruce, balsam fir, and jack pine may find a cool-temperature refuge and persist in the eastern BWCAW, even in a very warm future climate, but would be co-dominant with expanding red maple populations. Earthworms will continue to expand and facilitate these changes in tree species composition.

PROJECT RESULTS USE AND DISSEMINATION<
The project was highlighted in presentations by project manager Frelich several prominent venues:

1. Minnesota Soil and Water Conservation Districts webinar (statewide audience of MSAWCD staff), October 2, 2013;
2. The National Extension Educators Workshop, Cloquet, MN October 29, 2013;
3. Minnesota Climate Change Adaptation Workshop, Science Museum of Minnesota November 7, 2013 (very broad audience including many land managers from throughout the state; this also resulted in coverage in the Star Tribune and Minnesota Public Radio);
4. Climate Science Workshop for Teachers, University of Minnesota St.Paul Campus, November 9, 2013;
5. discussions with state staff directors in offices of U.S. Senators Amy Klobuchar and Al Franken, December 11, 2013;
6. Citizens Climate Lobby (Training in climate impacts on northern forests for ca 120 people, Minneapolis, January 25, 2014);
7. Jackson Middle School (A science immersion school in Champlin, MN), Expert Day presentations and workshops with ca 50 students, January 29, 2014;
8. Osher Life Long Learning Institute, Coffman Union, University of Minnesota, Minneapolis, lecture to ca 40 retired faculty, February 28, 2014;
9. Minnesota Master Naturalist Annual Meeting Keynote to ca 150 people, May 16, 2014, Camp Friendship, MN; and
10. Climate change adaptation planning workshop for National Park Service staff at Voyageurs NP, July 30, 2014, also attended by U.S. Forest Service and other agency personnel.

Publication in the form of a PhD thesis (David Chaffin) and at least 3 peer-reviewed journal articles will follow within about 2 years.