Marcia Roepke
Trail Time

Trail Time – Beautiful Winter

We’re having such a beautiful winter on the Gunflint Trail. The snow is fresh and deep. Today the sky was a pale blue with a few hazy clouds. Even though it was just seven degrees above zero, the sun was warm on my face as I sat in a sunny spot next to a jack pine, with just my dog and a hairy woodpecker for company. We’d been sitting there a while, Ursa and I, before the woodpecker joined us. He gave out quite a few scolding EEPS! when he spotted us, but soon settled down to tapping a birch tree, searching for his lunch under the tree bark. The air felt so still, and I would hardly have noted a breeze, except there was a large white pine nearby, standing tall, high above the rest of the forest, and I could hear a faint wind blowing through the pine needles. A friend of mine calls them wind trees. They whisper to us about the wind we cannot otherwise hear.

It’s still and silent and you could easily think that there is nothing going on in nature in wintertime. I can still see signs from last summer’s activity: the young birch saplings that the moose bent over to get to the tender leaves at the top; the Saskatoon shrub that the bear pulled down to reach the fat juicy berries. The summer mysteries are solved and behind us, but winter mysteries are happening above and below us constantly.

Last fall the lake water cooled from above, freezing from the top down. The floating ice thickened as the weather got colder and acted as insulation so the water below didn’t freeze. And neither did most of the fish and plants, but come fall,  everything slowed down. Plants stopped growing, storing energy in their roots. Frogs and turtles hibernated in the mud, where the water was warmer. Fish gathered in the deepest part of the lake and entered a state called torpor. Because of lake turnover in the fall, there was enough oxygen in the water to keep the fish alive until spring.

Lake turnover happens when the water at the surface reaches 50 degrees. At that temp, surface water is denser than the warmer deeper water and a convection current forms, forcing the deeper water upward. The water mixes and the deep water (the former surface water) brings oxygen to the lower depths of the lake.

Beavers stay busy all winter under the ice, and sometimes you can hear them eating their dinner of aspen bark while they’re in their lodges near the shore. Just be very quiet at a lodge and sometimes you can hear the munching without even getting too close. The aspen they stored under the ice in summer is their food pantry and they enter and exit the lodge below the ice.

The aspens themselves grow all winter. If you have ever whittled the bark off an aspen, you’ve noticed that beautiful green layer of inner bark — that’s the photosynthetic layer and that’s what allows the tree to grow when other trees are dormant. In other trees, it is only the leaves that carry out photosynthesis.

Conifer trees grow more slowly in winter, but they can still photosynthesize. The waxy coating on their needles retains water so they can keep absorbing sunlight to make food for the tree.

There’s a lot going on under the lake and under tree bark — and also under the snow. That’s the subnivean area where small mammals live out their secret winter activities. The subnivean refers to that space between the snow and the ground which is formed when there is over 6” of snow or more. The snow next to the ground sublimates due to the warmth of the earth. Sublimation means the snow goes from solid to gas without becoming liquid. Of course, some snow does melt, forming an icy ceiling that helps support the dome of snow above. Small animals move freely in this space, hunting for food and making tunnels and finding nesting materials. You can see animal tracks in the snow leading to these tunnels and also ventilation holes. In the spring, you can see all the little holes the mice and voles made through the grasses. Weasels are small enough to go through these snowy tunnels in search of dinner. Hunting from above the snow, owls can hear the movements inside these tunnels, then they zone in and punch through the snow with their bunched-up talons acting like fists, to grab their next meal. Barred owls will be mating soon, so their need for food intensifies before March, when they nest.  Their young are fledging just when rodent families start expanding in the spring.

We bipeds above the snow and ice match this busy movement of life as we roar down the snowmobile trails, whisper along the cross-country ski tracks and glide over the smooth wild ice on our skates. Sometimes we pause to drill holes and seek out the deep-water dwellers, dropping a line or two or fourteen.

At this time of winter, we stand on a cusp, and if you are still, and listen, you can feel the earth turning back toward the sun. February can seem like a pause in that movement, but the world is still turning, still moving toward warmth, even when it feels like it will be cold forever. Keep your face pointing toward the sun and share that warmth with others.

— Marcia Roepke