Less Snowfall may Harm Soil Quality and Tree Health, Study Suggests

Tree growth and water system quality may be negatively impacted by milder winters in the coming years, according to a new study.

Researchers from Boston University report that less snow cover associated with warmer winters will leave the ground exposed to prolonged freezing conditions, which will have consequences for trees and aquatic ecosystems.

Writing in the journal Global Change Biology, Pamela Templer and her collaborators report that soil freezing due to diminished snowpack causes root damage to maple trees and limits the trees' ability to absorb nitrogen and other nutrients in the spring months.

The lack of nitrogen absorption leads to increased runoff of nitrogen into groundwater, which the researchers contend can degrade water quality and even trigger widespread harmful consequences to the surrounding ecosystem.

"Most people think that climate change means hot, sweltering summer months, but it affects the winter as well," said Templer, an ecologist currently on fellowship at Harvard University.

Templer said that climate change has diminished winter snowpack across the past five decades and that it is likely to continue over time.

Snow is essentially an insulating blanket, protecting the ground from harsh cold air. In a two-year snow removal experiment, Templer and her colleagues shoveled snow off of sections in the Hubbard Brook Experimental Forest in New Hampshire to simulate the effects of a warm winter. The soil on shoveled patches of ground was as much as 10 degrees colder than soil covered by a blanket of deep snow. With less snow on the ground, soils could stay frozen well into spring, the researchers report.

"Results of this study provide direct evidence that soil freezing reduces root nitrogen uptake, demonstrating that the effects of winter climate change on root function has significant consequences for nitrogen retention and loss in forest ecosystems," the researchers wrote in the abstract to their study.