Northern Research Station News Releases

Warming Climate has Consequences Now and in Future of Wisconsin and Michigan Forests

Houghton, MI, September 20, 2014 - Between 1961 and 2011, the frequency of rainstorms of 3 inches or more increased by 3 times in Wisconsin and by 2.8 times in Michigan.  A new U.S. Forest Service forest vulnerability assessment suggests that more intense rainfalls are among the effects of a changing climate that will ripple through forest management, affecting infrastructure, wildlife and ecosystem restoration.

The assessment describes effects of climate change that have already been observed, projected changes in the climate and the landscape, and forest vulnerabilities in a 16-million-acre region of forest in Michigan’s Upper Peninsula and northern Wisconsin.

Along with heavier rainfalls, the region included in the assessment is experiencing warmer weather throughout the year, particularly with respect to mean minimum temperatures and winter temperatures. Ecological indicators are beginning to reflect these changes as well, as evidenced by differences in ranges of wildlife species and phenology.

“While there is uncertainty about exactly how climate change will affect the region, we know enough today to begin planning for a range of possible futures.” said Maria Janowiak, a climate change scientist with the U.S. Forest Service and the assessment’s lead author. This assessment is intended to give forest managers the best possible science on the effects of climate change, so they can make fully informed decisions about management today.”

“Forest ecosystem vulnerability assessment and synthesis for northern Wisconsin and western Upper Michigan: a report from the Northwoods Climate Change Response Framework Project” is part of the Northwoods Climate Change Response Framework, a collaboration of federal, state, academic and private partners led by the Forest Service’s Northern Institute of Applied Climate Science (NIACS). The report was published by the U.S. Forest Service’s Northern Research Station and is available online:

“Forests are vital to a whole spectrum of human needs, from the economy and jobs to recreation and clean air and water,” said Michael T. Rains, Director of the Northern Research Station and the Forest Products Laboratory. “Forest Service scientists and our partners are providing tools that enable foresters and other decision-makers to begin managing now for resilient and sustainable landscapes.”

The Chequamegon-Nicolet National Forest in northern Wisconsin is already applying science to forest management. Forest staff reviewed culvert sizing criteria to determine how the replacement of culverts and other infrastructure may need to be altered as precipitation patterns change and extreme precipitation events occur more frequently.

“The vulnerability assessments will help us think about and take actions to ensure the things people value on the Forest are here in the future,” said Paul Strong, Forest Supervisor of the Chequamegon-Nicolet National Forest. “For example, we are already thinking about how we can keep our cross-country ski trails more useable in years when snowfall may be light or spring arrives early. We are also considering how the trees in our campgrounds might need to be managed differently to ensure shade and aesthetics are maintained.”

The assessment also reports:

  • Projected climate trends for the next 100 years indicate a potential increase in mean annual temperature of 2 to 9 degrees Fahrenheit for the assessment area, with warmer temperatures occurring in all four seasons.
  • The length of the growing season increased by 12 days across Wisconsin between 1950 and 2006, with the greatest change in central and northwestern Wisconsin.
  • The date of the last spring freeze is occurring 5.6 days earlier on average, and the first autumn freeze is occurring 6.5 days later.
  • Mean annual precipitation increased by 2.0 inches, or about 6.5 percent, across the assessment area from 1901 through 2011.
  • The greatest change in temperature during the 20th century was observed during winter, with an increase in mean temperature of 2.2 degrees Fahrenheit and an increase in minimum (low) temperature of 3 degrees Fahrenheit.

Forest systems that are adapted to a narrow range of conditions or that contain few species are likely to be more vulnerable to changing conditions, the assessment concludes. Communities with higher diversity that are adapted to tolerate a wide range of conditions and disturbances are expected to be better able to persist under a range of plausible climates. In northern Wisconsin and western Michigan, upland spruce-fir, lowland conifers, aspen-birch, lowland-riparian hardwoods, and red pine forests are the region’s most vulnerable ecosystems, researchers found. White pine and oak forests are expected to be less vulnerable to projected changes in climate.

More than 40 scientists and forest managers from the Forest Service, universities, and other organizations contributed to the assessment, which is was conducted as part of the Northwoods Climate Change Response Framework, a collaborative approach among researchers, managers, and landowners to incorporate climate change considerations into forest management. The Climate Change Response Framework is led by the Northern Institute of Applied Climate Science, which is a collaboration of the Forest Service, Michigan Technological University, the Trust for Public Land, and the National Council for Air and Stream Improvement.

The U.S. Forest Service is an agency of the U.S. Department of Agriculture, a mission of sustaining the health, diversity and productivity of the nation’s forests and grasslands to meet the needs of present and future generations. The mission of the Forest Service's Northern Research Station is to improve people’s lives and help sustain the natural resources in the Northeast and Midwest through leading-edge science and effective information delivery.

The U.S. Forest Service manages 193 million acres of public land, provides assistance to state and private landowners, and maintains the largest forestry research organization in the world. Public lands the Forest Service manages contribute more than $13 billion to the economy each year through visitor spending alone. Those same lands provide 20 percent of the nation’s clean water supply, a value estimated at $7.2 billion per year. The agency has either a direct or indirect role in stewardship of about 80 percent of the 850 million forested acres within the U.S., of which 100 million acres are urban forests where most Americans live. For more information, visit


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Last modified: September 20, 2014