Rotten Log, The (PCEC)

Summary:

Many things depend on dead trees for food, shelter and/or nesting sites. Rotting logs also add nutrients to the soil for plant growth.

Grade Level:

5 and up

Recommended Setting:

Indoor or outdoor classroom

Outdoor Activity:

No

Location:

Potlatch Conservation Education Center at Cook’s Lake, Casscoe

Contact:

Education Program Coordinator, 870-241-3373

Duration:

One to two hours

Suggested Number of Participants:

20 - 25

Special Conditions:

One adult supervisor per 10 students; outdoor activities, weather permitting.

Objectives:

  • Observe organisms living on a rotting log.
  • Explain how the organisms interact with the log.

Key Terms*:

Decomposition

Humus

*See glossary for definations

Materials:

Clipboards

Field guides

Jars with lids

Magnifying glasses

Paper sacks

Pencils and paper

Background:

As a tree grows, it collects minerals and other nutrients from the soil and air to make new bark, roots, leaves, twigs and wood. When the tree dies, it decomposes and nutrients are released back into the soil.

Procedure:

  1. Examine a rotting log.
  2. Divide into groups of three to four.
  3. Give each group magnifying glasses (one per person if possible), four or five “bug” boxes or jars with lids, a pencil, markers or crayons, one or two sheets of paper, a clipboard and field guides (insects, spiders, reptiles and amphibians).
    • Note: Before taking them out, set safety guidelines such as avoid placing their hands into dark holes, releasing all animals after observing and sketching them and replacing the log in its original position after examining it.)
  4. Have the participants find at least one creature from the top of the log, under the bark and underneath the log or on the ground nearby.
  5. Have participants use blank paper to draw the plants, animals and fungi they find and write down where on the log they found each one.  Release the organisms back into the area where they were found.  Handle organisms gently to avoid injury.
  6. Go back inside and have each group explain what they found, where they found it, and how the organisms they found benefit from the decaying log.  Use identification keys, when available.

(Adapted from “A Guide to Environmental Education for National Wildlife Refuges and Fish Hatcheries in the Southeast Region,” produced by the U.S. Fish and Wildlife Service, Region 4, Atlanta, Georgia.)

Modifications:

Return to the classroom with their specimens, place them under dissecting scopes and, using keys provided, identify what they have collected.

Review:

  • What did you expect to find in a rotting log?
  • What did you actually find?
  • How did what you found in the fallen log help return nutrients to the soil?
  • Make a food chain/web using animals you found. (You may have to add some to complete your chain/web.

Glossary:

Decomposition – biological process by which dead materials are broken down into simpler forms of matter

Humus – dark organic part of soil formed from decaying plants and animals, often called topsoil, which improves the soil’s fertility and water-holding ability