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Redwoods

 

Overview

They are the giants of the earth, bigger than dinosaurs or whales. They tower over 67 meters (220 feet) high, outlive most other forms of life, and have inspired pioneers, poets, and presidents alike. They are the redwoods of California. Actually, the term "redwood" refers to several species. For example, the towering coast redwoods (Sequoia sempervirens) grow in the mild, misty climate along the Pacific coast of California and southern Oregon. The oldest among them is 2,200 years; the tallest measures 113 meters (370 feet). Their cousins, the giant sequoias (Sequoiadendron giganteum), live in the harsher climate of the Sierra Nevada mountains. These trees are more massive and live even longer. Although all redwoods are valuable natural resources, the coast redwoods are the focus of this Newton's Apple segment. Like all trees, the coast redwoods have developed a highly successful root, trunk, and leaf system using air, water, and sunlight to live and reproduce. The shallow roots of the redwood can spread laterally over 75 meters (250 feet) as they collect and send water and minerals to the leaves. The leaves, in turn, create food through photosynthesis and send the nutrients back down through the trunk to the roots. The unusual characteristics of the redwood's trunk have enabled it to survive the centuries. The outer layer of a tree's trunk, or bark, is made up of dead cells. In redwoods, the bark is fibrous and thick, often measuring 30.5 centimeters (one foot). The thickness of the bark and its lack of resin help redwoods resist damage from forest fires.Tannic acid in the bark helps the trees resist disease and insect infestation. The layers under the bark sustain the life of the tree. The phloem, cambium,sapwood, and heartwood each plays a role in the healthy growth of the redwood tree. Because of the high demand for their wood, coast redwoods have long been a target of the lumber industry. Ecologically, forests have felt this impact. Without the trees' roots in place, erosion plays havoc by clogging up streams with silt and destroying the watershed. Conservationist John Muir may have spoken for everyone working to save the redwoods when he wrote, "The clearest way into the Universe is through a forest wilderness."
  • Conservationists and the logging industry have long been at odds. How would you explain the issues?
  • What do you think our national policy should be toward logging the forests?
  • Can you identify areas near your home or school that suffer from ecological stress?

Activity

How does the height of a tree in your backyard compare to that of a 65-meter (214') redwood?
  • a tree
  • ruler
  • tape measure
  • graph paper and pencil
  • twine measuring at least 100 meters (328')
  • several friends
  • Select a tree to measure.
  • Standing near your tree, press the ruler horizontally against the bridge of your nose, holding the ruler at its end.
  • Flip the ruler vertically, making sure to keep it at a distance of one ruler's length from your face.
  • Walk backward until the top of the ruler lines up with the top of the tree.
  • Using the tape measure, calculate the distance between the tree and where you are standing. Add the measurement of your height to this calculation to find the approximate height of your tree.
  • Make a graph of the redwood tree, your tree, and your friends' trees.
  • To visualize your graph, try this. Find an open area outside. Using twine, measure the length of the 65-meter redwood. First measure the length of your stride. Have a friend hold the ball of twine. Holding the other end of the twine, count your strides to measure the length for the redwood. Once you reach 65 meters, have a friend stand in that spot. Follow the same directions to measure the length of your tree. Imagine your tree next to a giant redwood as you compare the two lengths of twine.

Questions

  • Using your knowledge of right triangles, can you explain why this technique of measuring trees works?
  • Identify the trees you have graphed. Can you make any generalizations about the height and type of trees you have measured?

Resources

  • Earth Works (1990) 50 simple things kids can do to save the earth. Kansas City and New
    York: Andrews and McMeel Books.
  • Hewes, J.J. (1992) Redwoods: The world's largest trees. New York: Smithmark Publishers.
  • National Audubon Society videotape: Rage over trees. PBS Video: (800) 344-3337.
  • Teale, E.W. (1954) The wilderness world of John Muir. Boston: Houghton Mifflin.

Additional sources of information


Arbor Day Foundation
211 N. 12th St.
Lincoln, NE 68508
(402) 474-5655
(membership and services)
Save the Redwood League
114 Sansome St., Room 605
San Francisco, CA 94104
(415) 362-2352
National Office of Project Learning Tree
1111 19th St. NW, Suite 780
Washington, DC 20036
(202) 463-2462

Community resources


Local Soil Conservation Service
Local university forestry department

How Tall Is It?<br>Measure the heightof your favorite tree.  Compare it to a California redwood.