Nature Notes

Fungi, Fermentation, and Fertilization

By Holly Einess

The East Side Trails, a favorite Arboretum destination of mine, are accessible only via x-country skis in winter. So on skis I go!

Winter East Side TrailWinter East Side Trail

I can feel the sun’s warmth in the still air. Chickadees are carrying on as though it’s a mild spring day, darting through the trees and singing a variety of songs, including the well-known “fee-bee” call most often associated with spring.I hear a woodpecker drumming in the distance; the extremely fast pace tells me it’s likely a hairy rather than a downy (remember: hairy = hurry).

I spot what looks like a charred marshmallow encasing a twig. It’s actually black knot, a parasitic fungus that affects primarily cherry and plum trees, including chokecherry. Come spring, leaves on infected branches either will not emerge, or they will wilt and die in early summer.

Black knot fungusBlack knot fungus

I ski by a stand of birches I admired last fall. Even without their yellow canopy the white papery bark looks lovely against today’s blue sky. As I finish up the North Ridge loop I hop on the Green Heron Trail, which takes me past a stand of highbush cranberry bushes. Not a true cranberry, they get their name from the similarly tart flavor of their fruit. The berries I find, though a bit shrunken, can be an important food for birds in late winter when other food sources have dwindled.However, the sugars in overwintered berries, once thawed,may ferment, and birds have been known to become intoxicated from ingesting them!

Highbush cranberry fruitHighbush cranberry fruit

A short way farther on I see the remnants of last summer’s ferns; only the spore capsules remain, casting shadows on the snow.

Sensitive fern spore capsulesSensitive fern spore capsules

A small tree commonly found in marshes, the speckled alder is monoecious, with male and female flowers on the same tree. The male catkins formed at the tips of year-old twigs last fall; in a month or so they will swell to twice their size and turn yellow as their pollen matures. The cone-like female catkins, arranged farther back on the same twig, likewise will enlarge in preparation for receiving the pollen.

Speckled alder catkinsSpeckled alder catkins

There are many criss-crossing and converging tracks on Green Heron Pondand I can only imagine the dramas that are played out when no humans are around! I head back to the trailhead near the Snyder Building, knowing the Arboretum’s critters will soon once again have the place to themselves.

Tracks on Green Heron PondTracks on Green Heron Pond

Holly Einess is a Minnesota Master Naturalist Volunteer

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