News
Shifting climate changing state's forests
KTSP.com, MN – March 8th, 2006
ST. PAUL (AP) - Minnesota's shifting climate is having an effect on its forests, with red maples encroaching up North and more pests invading in the southern part of the state, according to tree experts.
Lee Frelich, who has been studying trees in the Boundary Waters Canoe Area Wilderness for 18 years for the University of Minnesota, says he's witnessed dramatic changes. Winters are milder and summers are wetter.
"There is a lot more red maple," said Frelich. "And red maple's a species that normally would not be part of the boreal forest in the Boundary Waters. The climate used to be too cold for red maple."
Frelich said the warmer summers have kept wildfires in check, giving the red maple a chance to flourish.
But the red maple's gain is a loss for the native northern pines, which have historically dominated the forest. But Frelich said they're not reproducing as well now as the red maple.
Minnesota has three biomes, or regions with distinct plant life and climates - the boreal forest in the north, deciduous forests of oak and maple in the central part of the state, and the prairies and savannahs of southern Minnesota. Even a small change in a biome's climate can cause a big change in the vegetation, sometimes quickly.
If Minnesota's climate continues to get wetter, the woods could end up looking more like Ohio where poplar, sycamore and walnut trees are common, Frelich said. If the climate becomes drier, the forests will retreat and the landscape will look similar to the grassland around Omaha.
That's worrisome for people like John Rajala, a fourth-generation woodsman whose family's business owns 30,000 acres of forest land, mostly in Itasca County.
Rajala says success in the wood products business depends on high quality trees, like white birch, which have been more difficult to find in recent years.
Rajala said the changes could be due to warmer temperatures. But he thinks other explanations may be just as valid, like the age of the trees. He said many of Minnesota's white birch are near the end of their natural lifespan. And he said people are planting fewer of them, because aspen trees are more valuable for paper-making.
Southern Minnesota fruit tree growers have noticed changes, too.
Ralph Yates, who farms 200 acres of apples near La Crescent in southeastern Minnesota, said the mild weather has brought more unwanted pests to his orchards.
"These populations aren't knocked as heavily as they would be in a traditional Minnesota winter," said Yates. That leads to more expense trying to control the pests.
Frelich said many Minnesotans may not have noticed the changes yet, but predicted that it won't be long before they will be hard to miss.
"I'd say if the climate stays as warm as it is now or gets warmer, within 50 years anybody would be able to notice a major change in the Boundary Waters - with much more oak and maple, a lot less spruce and a lot less pine," he said.