Friday, October 12, 2007

Fall Happenings

Nature Watch
October 12, 2007

By Susan Benson
Director of Education
Cable Natural History Museum

This is a great time for hiking! Most insects are gone, and most deciduous trees are now bare up here in the north woods, which means that if you’re walking through the woods, you get to see the countour of the landscape better than you would during the summer, when a full canopy of leaves hems in your field of vision.

It’s a great time for the young at heart to jump in leaf piles too. While you’re rolling around in the leaves, you might wonder what ultimately happens to fallen leaves. Unless they’re raked up and removed, leaves will break up and start decomposing into a layer on the forest floor that’s called humus.

Humus comes in two varieties, mor and mull. Mor humus is found in primarily coniferous forests whose floor is covered with a thick carpet of needles and leaves that decompose very slowly. Forces that decompose mor humus include fungi, springtails and mites; bacteria and earthworms are rare.

Mull humus is typical of deciduous forests—aspen, maple, birch, etc. Mull is either neutral or alkaline compared to the acidic mor humus, and the soil it creates tends to be rich and dark. In mull humus, bacteria are high in numbers, as are earthworms, slugs, millipedes, and lots of insect larvae.

On the edge of the forest, or in abandoned fields, you may notice milkweed plants, whose lavender summer flowers have now turned into large, slipper-shaped seed pods. The milkweed plants themselves grow from two to six feet high, and usually have a single, simple stem with opposing, oval-shaped leaves. The top surface of the leaves is smooth, but the bottom surface is hairy.

The plants’ large seed pods have a warty outer skin filled with downy fluff that will carry the seeds on the wind like a parachute. It’s said that this seed-fluff was used by Native Americans to insulate moccasins, and was also used as stuffing in military life jackets during World War II. The dried empty seed pods of the milkweed also were used as Christmas tree decorations by early pioneers.

Cattails are another plant that disperses its seeds in the fall via tiny parachutes on the wind. This wetland plant is very common to Wisconsin’s marshes, ponds, ditches, rivers and lakes. Cattails grow in dense groups, with up to ten-foot-tall sword-like leaves pointing up to the sky with a hearty stalk standing between them. Atop the stalk is the familiar long oval brown spike. Above the spike will appear a yellowish flower between May and July, but by September or October, after the flower has been pollinated, you’ll see the brown flower head pop open and get very fluffy. This means that the seeds are ripe and ready to float through the air in cottonball-like clumps, ready to start new plants.

You’re probably pulling out your cold-weather clothes and packing away the shorts and sandals for the season. Many animals do something similar, growing thicker coats of fur or adding insulation in the form of fat. The snowshoe hare has started to exchange its thin brown summer coat for thick, fluffy white fur that will provide camouflage as well as insulation for the snowy winter. The transformation starts with the ears and feet, and the full makeover takes about 10 weeks. Some people call this animal the “varying hare” because of this seasonal color change.

By the way, have you ever wondered if there is a difference between a rabbit and a hare? They are different: a snowshoe hare looks like a rabbit at first glance, but in general hares have longer ears, very large hind feet, and longer legs made for jumping. Hares are also born with their fur and their eyes open, unlike the rabbit. The snowshoe hare is slightly larger than the cottontail rabbit as well.

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 43570 Kavanaugh Street or on the web at to learn more about exhibits and programs.

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