No one will be surprised to know that Something Wild hosts Dave Anderson from the Forest Society and Grace McCulloch of NH Audubon love to wander around in the woods no matter the season.
Winter snowfall tends to peak in January and February, and the snow in the forest is often deepest in this late winter period. But if you get out into it, you realize that it’s not a uniform depth, and there are many smaller microclimates within the forest.
The snow is intercepted by a conifer snow umbrella that keeps the snow off the ground. The thick interlacing needles of hemlock, pine, and spruce intercept about 60% of the snow. This phenomenon also insulates the space beneath.
If you’re a deer or moose, you seek out these spots for shelter. They’re known as deer yards, a snug place for deer to bed-down with dense cover overhead and protection from brisk northwest winds.
When there’s enough contiguous coniferous canopy, deer yards can actually cover hundreds of acres. You can see this in the White Mountain National Forest, and higher elevation areas of the state.
The lack of snow cover also makes it easier for deer to walk around the understory to well-established trails that radiate outward to food and "browse."
A deer’s stomach biome changes, too, adapting digestion to a winter diet called “browse.” Browse includes twigs, buds, low hemlock boughs, or bark, although the gummy pine pitch isn’t palatable. Browse is lower quality food but it sustains deer for months until the snow melts.
It’s not just deer that benefit from the insulation of snow-covered conifers. Overwintering birds, like the common winter-adapted black-capped chickadee, use evergreen trees and shrubs as a place to escape the cold and wind.
And owls take advantage of the microclimate within dense pine and spruce trees for protection from snow and rain, and to reduce heat loss.
In warmer seasons owls use dense conifers to hide from harassment by crows. And the high branches of conifer trees make ideal hunting perches for owls spotting small prey like voles or mice in the snow. Those little rodents are taking advantage of the conifer cover and exposed leaf litter to find roots, bark, and seeds.
Forests in the state transition from hardwoods in the south and at lower elevations compared to the northern forests of the state, where forests have a higher concentration of conifers. And, of course, winters are longer and snow is deeper overall than in southern New Hampshire where more shallow snow doesn’t last as long.
The deciduous trees and shrubs of southern New Hampshire don’t catch snow like conifers. They have a different phenomenon that also causes there to be less snow under the trees.
Solar radiation is absorbed by the exposed dark tree bark and branches and radiated back to the ground, and that leads to snow melting around trunks creating “tree wells.”
One plant helps another by keeping nearby plants just a little bit warmer.
Get out in the snow this winter and you’ll find there are a lot of variations to snow depth and how the wildlife respond.
Something Wild is a partnership of NH Audubon, the Forest Society and NHPR.
