UNH
Researchers Find Northern Forests Have Lost Crucial Cold, Snowy Conditions
University of New Hampshire
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| Photo credit: MaxPixel |
“Winter conditions are changing more
rapidly than any other season and it could have serious implications,” said
Alexandra Contosta, research assistant professor at UNH’s Earth Systems
Research Center. “Whether precipitation falls as snow or rain makes a big
difference, whether you’re talking about a forest stream, a snowshoe hare or
even a skier.”
In their study, recently published in the journal
Ecological Applications, the researchers looked at the last 100 years of weather
station data from northern forests across the United States and Canada and the
impacts on ecosystems and people.
They found a significant decline in “frost days,” when minimum temperatures dip below freezing, and “ice days,” when maximum temperatures never rise above freezing.
They found a significant decline in “frost days,” when minimum temperatures dip below freezing, and “ice days,” when maximum temperatures never rise above freezing.
Researchers say that people tend to
view cold and snowy weather as burdensome. Yet winter is important for many
ecosystems that influence water, wildlife, forests and people.
For instance, cold temperatures help prevent the spread of diseases like Lyme disease and West Nile virus through insects like ticks and mosquitoes, as well as help manage insects that are detrimental to trees, like the hemlock wooly adelgid and eastern pine beetle.
For instance, cold temperatures help prevent the spread of diseases like Lyme disease and West Nile virus through insects like ticks and mosquitoes, as well as help manage insects that are detrimental to trees, like the hemlock wooly adelgid and eastern pine beetle.
A deep and long-lasting snowpack
also insulates soils from frigid air temperatures, which prevents roots from
freezing, promotes soil nutrient cycling and provides wildlife habitat for
burrowing animals.
Snow cover is as important to the economy and culture of the northern forest as it is to its ecology, especially for timber harvest, maple sugaring, winter recreation activities like skiing and ice skating, and hunting and fishing essential for indigenous peoples.
Snow cover is as important to the economy and culture of the northern forest as it is to its ecology, especially for timber harvest, maple sugaring, winter recreation activities like skiing and ice skating, and hunting and fishing essential for indigenous peoples.
“What makes our work unique is that
we considered the human effect of climate as well as the ecological or
meteorological aspects,” said Contosta. “For example, we looked at “mud days,”
when temperatures are above freezing and no snow cover is present, which can
impact not only forest soil nutrients but also loggers who are not able to reach
certain areas that can only be harvested with deep snow.”
Researchers say much of what is
understood about the effects of climate change on ecosystems is based on
research conducted during the growing season. Researchers say it’s more common
to hear about summer climate like drought index or heating degree days.
They feel more research needs to be done during the so-called ‘dormant’ season to fill in the key gaps about how forest ecosystems respond to climate change.
They feel more research needs to be done during the so-called ‘dormant’ season to fill in the key gaps about how forest ecosystems respond to climate change.
This study was funded by the
Northeastern States Research Cooperative (NSRC), with additional support to the
Hubbard Brook Research Foundation from the Canaday Family Charitable Trust, the
Lintilhac Foundation and the Davis Conservation Foundation.
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As one of the nation’s highest-performing research universities, UNH partners with NASA, NOAA, NSF and NIH, and receives more than $110 million in competitive external funding every year to further explore and define the frontiers of land, sea and space.