July 10th, 2013 by

Red maple

Red maple. Credit: geneva_wirth/Flickr

Back in the Winter 2013 issue of American Forests magazine, we visited Harvard Forest in Petersham, Mass., where researchers are heating the soil with buried electric cables to gain some insight into how the changing climate will affect soil organisms like microbes and ants. So my interest was piqued when I read in E&E News about similar experiments with an important twist being carried out in the White Mountains of New Hampshire.

The hypothesis that climate change is expected to lead to warmer soils seems intuitive, but it actually doesn’t hold true throughout the year. In New England, as the climate warms, winter soils are getting colder. The key to this seeming paradox is snowpack.

We’ve written before about how snow cover serves as a warm, cozy blanket for many soil organisms and other living things under the snow. Tree roots are no exception. Without the blanket of snow, water in the soil freezes, expands and often cuts and damages tree roots. When spring comes, the damaged roots’ ability to take in nutrients from the soil has been compromised.

That’s why researcher Pamela Templer is going one step further in simulating future climates by taking colder winter soils into account. At Hubbard Brook Experimental Forest in White Mountain National Forest, she has wired four plots that are home to three red maples each. On these four plots, the four-inch-deep cables will warm the soil to simulate increasing summer temperatures — an increase of five degrees Celsius during the growing season. But, here’s where it gets more interesting: On two of those plots, she shovels off the snow that currently falls during winter, leaving the soil exposed to mimic the loss of snowpack predicted over the next 100-200 years. The maples will be monitored for root growth and other metrics of health on all six plots.

The experiment, which began last summer, will run for five years, and researchers hope it will lead to a better understanding of the effects climate change will have on New England’s forests. For an area of the country that relies on the forests not only for clean air, clean water and aesthetic beauty, but also for much of its economy, understanding how climate change will affect forests could mean getting a glimpse into the future of local communities.