Forest Preserve District of Cook County, Illinois
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Rotting Logs
Nature Bulletin No. 55   March 2, 1946
Forest Preserve District of Cook County
Clayton F. Smith, President
Roberts Mann, Superintendent of Conservation

There is drama in a rotting log. Apparently lifeless and useless there on the ground, it harbors thousands of living things within and beneath it. Feeding on the wood of the log, living and dying, generation after generation of them, they convert it back into minerals which a fertile healthy forest soil must have. They also add the humus which not only helps the soil to hold its moisture but also aids in making the soil minerals usable as food by plants, including trees. Finally there is nothing left but crumbling punk shot through and through with the hyphae, or roots, of molds and mushrooms. Some of the common lower plant and animal forms found in a rotting log in our forest preserves are these.
  • Bacteria
  • protozoa
  • millipedes
  • molds
  • round worms (nematodes)
  • roaches
  • fungi (mushrooms)
  • land snails and slugs
  • crickets
  • lichens
  • earthworms
  • fly larvae (maggots)
  • mosses
  • bugs
  • beetle larvae
  • centipedes
  • beetle

There is an interesting story in the way each of these plants and animals attacks the rotting log. The boring beetles, for instance, chew up the wood but the digestion is done by hosts of microscopic animals (protozoa) packed in their intestines. Earthworms have ferments in their saliva which convert the woody substances into sugar.

Dead and dying trees, while they stand, furnish homes for many mammals and birds such as bats, squirrels, raccoons, possums, wrens, bluebirds, woodpeckers, wood ducks and owls. They furnish food for many of these. When they fall and lie there rotting they furnish homes and food for many other mammals, snakes and insects -- winter and summer.

They play a vital part in encriching the soil, keeping it fertile and maintaining the abundant variety of life to be found in our natural forest.

Woodsman, spare that dead tree !

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