I'M LOSING MYSELF in a prickly-ash bud. It didn't look like much from the trail, a mere rusty knob among hundreds dotting a chest-height shrub. But up close the color intensifies; soon it shines almost scarlet against the cinnamon bark. What seemed a smooth surface reveals bumps and valleys, covered in a delicate fuzz. I spot the sharp, scaly formation where last year's leaf was attached, and the scrawl of intricate white lines and dots that circle the twig like a prehistoric engraving. Further down, there's a short, perfectly tapered spine with a purple sheen. I barely notice when the rest of the group disappears down the trail.
There are a dozen of us out on this Sunday morning, tromping through the drifts in Minnehaha Park. The rumble of trucks along Hiawatha Avenue drowns out our guide's voice on occasion, and the chirp of a chickadee is cause for momentary distraction. But mostly we're riveted to the man with the carmine basque who pulls down twigs, picks up dry leaves, and explicates the art of "identifying wildflowers and trees in their dormant state." It's a winter botany tour, a hunt for life in the frozen landscape.
"You'll assume that this is a basswood," Bob Bergad calls, standing near a tree just taller than himself. His clipped diction reveals both New England roots and the botanist's passion for detail. "It has the same smooth, gray bark. But if you look closer, you'll notice that the bark is indeed not smooth. It has grooves in it, ridges that seem to form a network. And while the buds on the basswood are reddish-brown in color and round, these are elongated, sharp-pointed and yellow--a mustardy yellow, a Plochman's Chicago-style mustard color." A laugh bubbles up from the group, but Bergad is dead serious. Such is the level of exactness needed to identify the yellow-bud hickory, also known as the bitternut, Cardya cordiformis, relative to the pecan. "They're not all that common here," Bergad announces. Heads nod in satisfaction.
We trudge on. The snow has an odd texture on a day like this--not powdery as in early winter, nor covered with the sharp crust that follows the January thaw, but coarse-grained and soft-contoured, with a mother-of-pearl sheen under the trees. It tempts you to walk on it, only to swallow your Sorrels with a mischievous crunch. "We need to use caution in areas such as this," Bergad warns from ahead. Wandering off the trail, he explains, packs down the snow over the trilliums, the wild ginger, the blue cohosh that grow on the hillside. "And we've learned that mice and the like don't actually hibernate. They dig their tunnels under the snow, and when we walk on top we can crush them or trap them in there." The group falls into a neat single file.
Bergad stops at another tree, pointing to the bright lime-green blotches along its bark: lemon lichen, one of the few in its family that actually has a name. Lichens are among the most ancient of life forms, mysteriously capable of living on water and sunlight alone. They're also an environmental indicator species: Incapable of filtering out toxins, lichens accumulate them in their cells until a poisonous level is reached. They've survived here, in what Bergad calls the "urban wilderness" of Minnehaha Park, but that could change. The state and the city want to build a six-lane highway just up the hill from where we're standing, to turn Hiawatha into a true commuter route. Some of the people are here on this tour because of this possibility, to gather arguments for the fight against the road. But they're not talking about that now. They're too busy inspecting the lichen's fuzzy pattern, imagining shapes the way you might with clouds.
The trail leads downhill, into the Mississippi River bottomlands. The group slows down. People fall out of line to pick up dead leaves, count lobes, examine the structure revealed as dead cells fall away. "Another thimbleweed," someone says, holding a gossamer flowerhead against the light. Rodent tracks lead across the snow where yesterday's powder hasn't melted. Scorched remnants of a campfire and a used condom point to the presence of humans.
This is how you start looking at things after a while following Bergad around; cutting sign, decoding evidence, reading traces of life past and future. And the less there is to observe, the more you see. "To identify a tree in the growing season, you would look at the shape of the leaves and perhaps the fruits," Bergad says. "You might never even look at the bark, which can be extremely characteristic. The hackberry, for example, is covered with tiny, wart-like structures that are stacked close, next to and on top of each other. It always reminds me of Manhattan, when you go down over it in an airplane."
Sometimes you even witness a small miracle. There's a patch in the park where the snow cover thins, and water tinkles slowly from the sandstone. There, Bergad has been checking on the skunk cabbage, an unassuming perennial that smells just like you'd guess and is distinguished by a defiant metabolism that actually thaws the soil around it. Soon--perhaps by the time you read this--the clubby flowerheads will rise, melting the snow with 60-degree heat.