For nature's sake, let it snow

It looks like all of this snow heading towards the midwest is good for trees. Below, find an article from Brian Nearing (timesunion.com)

A benefit in drifts, researcher says

By BRIAN NEARING Staff Writer, timesunion.com

Updated:08:26 a.m., Tuesday, February 1, 2011

ALBANY -- Having developed an uncomfortably close relationship with snowblowers, shovels and icy boots, some people may have had enough of snow this season. But while vexing to some, winter's white blanket has environmental benefits that help protect trees and soil, and keep groundwater clean.
To those feeling pummeled by winter this month: It's definitely not in your head. This winter, or more specifically January, has been one of the snowiest ever in the Capital Region. With 33.8 inches for the month at Albany International Airport as of Friday, the month already ranks sixth in snowfall records that date back to 1885, according to the Albany office of the National Weather Service.

But it's way too early to tell whether this year will set records. The current seasonal total of 46.9 inches is less than half what fell in the top five snowfall years.

This year's throwback winter is more than just fun for skiers and a headache for those who see winter and recreation as a contradiction in terms. Cold and snow function as a barrier to invasive pests, keep trees healthier, and protect soil chemistry in a way that makes groundwater, rivers and lakes cleaner.

At the Cary Institute of Ecosystem Studies in Millbrook, Westchester County, researcher Peter Groffman studies the effect of snow cover on biological and chemical processes in soil and trees. To think about Groffman's work, it helps to see soil as something "alive" and changing, with microbes fueling chemical decomposition and chemical exchanges all winter long underneath the snow.

But snow cover has gradually lessened in the northeast over the last three decades, as one consequence of man-made climate change. Groffman, a microbial ecologist, looks at what happens to those processes when a blanket of snow thins out.

The number of extremely cold days also have been dropping in the northeast, another outcome of climate change. And that has opened the door to invasive pests like the hemlock-devouring woolly adelgid (a-DEL-jid) insect, a southern invader that has been gradually working its way northward as winter temperatures gradually climb.

"You need temperatures of at least 25 below to hold back the adelgid," Groffman said. "The last time we had that temperature in Millbrook was 1994. And now we have the adelgids, and they are coming to Albany."
Paradoxically, a gradually warmer world with less snow will mean colder soils, at least initially. That happens because ground, once covered by snow, is effectively insulated, and does not get as cold or freeze as completely as bare ground does. Less snow will mean soils will freeze more often.

During the winters of 2002-03 and 2003-04, Groffman worked in the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire to study what stripping a blanket of snow does to trees and soil. He shoveled off eight 10-yard-by-10-yard plots in stands of maple, birch and beech trees.

He found that bare frozen soil meant that microbes slowed or stopped, and also stressed tree roots -- particularly fine roots -- which were twice as likely to die as roots protected by snow cover, said Groffman.
This contributed to a buildup of nitrogen in soil, which is a nutrient caused by decomposition of organic matter.

Not being absorbed as much by weakened trees with damaged roots, more nitrogen got into groundwater, eventually making its way into streams, rivers and lakes. Nitrogen helps fuel the growth of algae and microscopic plants, which makes lakes and streams more clouded, a process called eutrophication.

"You end up with a water pollution problem," Groffman said. "When you lose snow and extreme low temperatures, you end up with these negative impacts. From an ecosystems services point of view, I can say that snow is good."

Peter Groffman's study can be found online at http://blog.timesunion.com/green.

Reach Brian Nearing at 454-5094 or bnearing@timesunion.com.