Minnesota Forest Ecosystem Vulnerability Assessment and Synthesis
Climate change will have direct and indirect effects on forests in Minnesota. “Minnesota Forest Ecosystem Vulnerability Assessment and Synthesis” assesses the vulnerability of the state’s northern forests to climate change.
This assessment is a product of the Climate Change Response Framework (www.forestadaptation.org) and was developed with the contributions of more than 40 co-authors from organizations including the Chippewa and Superior National Forests, Minnesota Department of Natural Resources, University of Minnesota, conservation organizations, tribes, private industrial landowners, and others.
Minnesota's climate has been changing over the past several decades. In addition to observed temperature and precipitation data, long-term records that track seasonal events also show clear evidence of change. Spring leaf-out dates, lake-ice duration, and bird migration patterns all show that spring is generally advancing earlier in the year.
Climate projections for northern Minnesota suggest that conditions that promote large wildfires such as the Pagami Creek fire in September 2011 may become more common, as summer and fall become warmer and drier. An increase in wildfire activity may benefit some fire-dependent forest types in northern Minnesota, such as jack pine and oak woodlands.
Acid peatlands, a common lowland forest system in northern Minnesota, were determined to be most vulnerable to climate change. Black spruce and tamarack are projected to decline in suitable habitat and biomass by the end of the century, and altered precipitation patterns are expected to disrupt the hydrology of peatlands.
Photo by Stephen Handler, US Forest Service.
Results from three forest impact models (Tree Atlas, LANDIS-II, and PnET-CN) contributed to the vulnerability assessment, in addition to published literature and input by local forest managers and researchers.
Aspen is the most abundant and most economically important tree species in northern Minnesota, and it is typically managed in even-aged stands with rotation ages between 35 and 60 years. The authors of the vulnerability assessment concluded that managed aspen stands have moderate to high vulnerability to climate change over the next century.
The possibility of increasing drought stress and interactions among multiple stressors, such as pests and disease, were the major factors driving this conclusion.
Trees are not the only concern. One of the major management implications of climate change for forest managers may be that infrastructure on forest land (roads, bridges, and culverts) may require more investment and maintenance as intense storms – such as the June 2012 rainstorm that damaged this northeastern Minnesota road – become more common.