INRS State Scientific Surveys
GRADE LEVEL: K-3
SUBJECTS: Science, Library Science, Language Arts, Art
SKILLS: observation, critical thinking, library research
OBJECTIVE: Students will learn how "dead" trees are actually alive with activity and
provide habitat and food for insects, birds, and animals and return nutrients to the
soil.
BACKGROUND:
A dead tree may look lifeless, but actually it is teeming with activity - the
activity of live animals. Dead trees have features that live trees do not - features
that attract more than 85 species of animals in Illinois.
Bugs Love Them. Many species of insects and other invertebrates (animals without backbones) feed on and live in dead trees. They bore holes in these trees to build their nests. These tiny animals provide food for many other larger animals. But that's just the beginning of the story.
So Do Birds. Many birds, especially woodpeckers, love to feed on the insects that live in dead trees. These birds feed on insects by making holes that insects have bored larger. They eat the insects and sometimes they make the holes so large that they move into them themselves. When they leave the holes, other animals move in, including squirrels, raccoons, and opossums. Lots of other birds may live in dead trees, or at least use them. Owls, hawks, and fly catchers, for instance, perch in dead trees looking for prey to eat (mice, insects, and small birds). They have a very good view because there are no leaves to block their vision.
Home Sweet Home. When limbs fall off trees they make brush piles on the ground. These piles provide homes for many animals. Insects move right in. And so do the animals that eat insects, including skunks, lizards, birds, and many others. Rabbits don't eat insects, but they are quite comfortable living in the shelter of brush piles.
When Fish Live in Trees. When trees that live on the edge of lakes or streams
die they drop their branches into the water. Eventually, the tree may fall into the
water. These branches and trees make excellent places for small fish to hide, a place
where many fish raise their young, and a very good hunting ground for larger fish.
How Old Trees Become New Trees. Eventfully, dead trees fall down. Insects, animals and bacteria continue to live in them as they decay. On the ground a dead hollow tree might become a home for a den of rabbits or foxes. Finally the tree decays completely and returns its nutrients to the soil. Good soil is made up of older plants that have died.
PROJECTS AND ACTIVITIES:
Write each of these animal names on an index card and distribute them to your
students: Squirrel, Raccoon, Hawk, Opossum, Bluebird, Black snake, Owl, Bat,
Woodpecker, Tree frog, Wood duck, Beetles, Mouse, Flying squirrel. Have pictures of
the animals on the bulletin board. Each of these animals uses dead trees. Ask your
students to imagine ways that these animals might find a dead tree useful. Students
might be assigned an animal and asked to draw or find a picture of it. Pictures could
be collected and pasted onto a poster size diagram of a dead tree. Features like
holes and nests should be added.
Ask students where the leaves that fall to the ground in autumn have gone by spring. Explain that dead trees eventually lose their branches and fall down, returning to the soil nutrients for other trees and plants. Discuss with students how this same principle is used by people who return their grass clippings to the lawn, make compost piles, or turn their garden under in the fall. Visit the perimeters of the school yard to find evidence of plant material that is decaying and returning to the soil. Is there evidence of insect activity in this decaying material?
In stories, dead trees are often portrayed as scary. Find a picture of a dead tree in a story book and discuss how it is portrayed. Have the class create a scary story involving a dead tree. Students must be able to explain any scary happenings with natural causes. Snakes, for instance, might be around dead trees to catch mice. Owls at night make ghost like sounds. Bats may live under loose sections of bark. White trunks and branches might look like skeletons in the moonlight. Go outside and look for dead trees and branches and any animals living in them.
EVALUATION:
Have students draw a picture with the title "What Good Is a Dead Tree?" The picture
should show as many ways as students can think of that dead trees are useful. Ask the
students "Do fish live in trees?" Did any students include fish in their pictures?
EXTENSIONS:
As a class project, make a mini compost pile in a suitable container such as a 3-pound
coffee can with ventilation holes or 2 liter plastic beverage bottles (see
references). Add dead leaves and small twigs during the school year, stirring
frequently. Measure and keep a record of the amount of decomposition that takes place
each month. Have older students calculate the rate of decomposition. At the end of
the school year, make a special short field trip to a young tree and fertilize it with
this compost.
VOCABULARY:
invertebrate, bore, decay, nutrient
Next lesson - A Little Help from Their Friends