A Chill in the Air

November sits on the edge of winter, when in the Northwoods liquid water becomes solid. So, it is the perfect time to walk—briskly, to stay warm—around the edge of a lake or marsh as it begins to freeze. If you keep your eyes and ears open, the season's beauty will be evident even without pausing and letting the wind whisk away your hard-earned warmth. 

Needle ice crunches under boot soles most satisfyingly. By the magic touch of Jack Frost, a patch of soil that was soggy in summer grows shimmering filaments, pillars, and plumes overnight. After ice begins to form at the surface, water nearby that’s dropped below 32 degrees F migrates toward the crystals. Where the ice and supercooled water meet, ice grows and expands perpendicular to the surface, which usually means it grows up. As they rise, the growing crystals carry bits of soil, small pebbles, or whatever’s nearby. The miniature worlds they create are delicate and whimsical, but once the ice melts, the soil becomes loose, fragile, and easily eroded.

Winterberry holly bushes grow in the damp soil, too. All summer long, their pointed-oval leaves blended in with everything green. Now, crimson berries glow against the drab brown of bare twigs and dried cattails like red sugar on holiday cookies. We still only notice half of the shrubs. Male flowers are born on separate plants. They release their pollen in spring and then return to obscurity. Females bloom and grow these cheerful baubles. The low-fat content of the berries means that they don’t go rancid. This provides winter cheer for us, and late-winter starvation food for forty-nine species of birds.

Rough-legged hawks like the one soaring above the marsh won’t be swooping down to eat the berries, though. Their preferred food is lemmings plucked from the Arctic tundra. Meadow voles provide a good substitute when they migrate south for the winter. To stay comfortable year-round in such chilly places, their legs are “rough” with feathers all the way to their toes. Larger than a red-tailed hawk but smaller than an eagle, the quickest way to identify this visitor is to look for the black patches on its belly and wrists. 

The hawks may be silent, but snow buntings chatter excitedly with the dozens of friends in their winter flock. Their twitters and buzzy calls rise as something spooks the group into a quick tumult before they return to foraging in the weeds. They, too, have feathered feet, spend summers in the high Arctic, and consider the upper Midwest far enough south for the winter. Males especially are loathe to travel too far away from the rock crevices where they nest. If he takes too long to return in the spring, all the good spots will be taken. But they do need to travel far enough to find seeds not buried by snow. The gravel shoulders of plowed roads seem like a good place to grab a snack, but I once found one at a trailhead stuck in a car’s grill. It was a good reminder to slow down. 

White pine needles dangle from the bare twigs of a tamarack tree like rusty orange tinsel. Crushing one between my gloved fingertips, I inhale the fresh scent of the pine’s protective chemicals. Although we call them evergreen, white pine needles aren’t truly everlasting. Each endures about three years, so the tree replaces about a third of its needles each year. That requires far fewer resources than starting from scratch. Fresh green needles, protected by their waxy coating, can rev up their photosynthesis engines and make sugar for the pine on warm days, year-round. 

Short, thin, tamarack needles, on the other hand, carpet the trail with fine filaments of gold. Not a single one remains attached to the spur branches that make the twigs look warty. Next spring, the tree will have to grow a whole new cluster of ten to thirty-five needles from each of these little nubbins. Usually, trees with cones keep their modified leaves year-round. Tamaracks are the deciduous exception. Several theories explain why this behavior helps. Perhaps it helps the tree shed snow a little better—their natural shape is certainly not as snow-tolerant as the bending bows of balsam fir. Perhaps getting a new wardrobe prevents insect damage from building up from year to year. Perhaps the sparse needles on this shade-intolerant tree collect summer sunshine so efficiently that they don’t need to waste energy by toughening up enough to work through the winter.

Late fall sunshine isn’t nearly as powerful, but as the thick, gray clouds part to let a few rays through, I pause to see if they’ll feel warm on my face. They don’t. A chilly breeze ripples the water's surface as if to steal the lake’s heat, too. The season of hard water is well underway!

Emily M. Stone is a naturalist by birth, training, profession, and passion. She explores the Northwoods with an eye toward using science to make stories come alive.