Smithsonian National Zoological Park l Friends of the National Zoo



Is There Life in a Decomposing Log?

Teacher Preparation and Set-up

Depending on the skill level of your students, and the time available to conduct the activity, it is highly recommended that the teacher locate logs in different classes of decomposition within walking distance of the classroom before the scheduled outdoor activity.

If decomposing logs can’t be found nearby, or weather will be inclement, bring decomposing logs or leaf litter into the classroom. Arrange the logs or leaf litter into stations around the classroom.

Rotting logs at National Zoo

Logs "planted" at the National Zoo to use in education programs.

Another option is to “plant” logs in your schoolyard habitat, garden, or local natural areas on or near school grounds. The National Zoo has planted logs near its Invertebrate House. In spite of heavy use by students, these logs always seem to have something living under them!

Teams of two to five students can each be assigned a log to investigate. Emphasize cooperation among students, perhaps assigning roles to each team member before the activity.

Determine whether it is appropriate to roll the log over to explore the bottom side. This will depend on the age and skill level of your students, as well as the size and setting of the rotten logs you select for study.

A log is a living system, and you never know what you may find underneath. If you chose to have your students roll the log, there are some simple instructions for the safety of your students and of the species that call the log “home.”

  • Students should all be on one side and roll the log so that they are behind it as they expose the underside. If there are surprises, the children will have the log in front of them.
  • When finished with the lab, roll the log back into its original position, and restore the leaf litter to its original state. Any species that they were examining should be held until the log is back in its original position, so they don’t get crushed, and then released on the edge of the log.

You may choose not to roll the log at all. Some logs are too big to handle safely, or are too decomposed to roll. Your students will find plenty of species on the surface, under the bark, and around the base of the log. Depending on the class of decomposition, your students can gently dig into the log itself to find species.