show #1211

Peggy learns the amazing history of the redwoods. Segment length: 8:29

Contents

Insights &Connections
 

Vocabulary


Resources


Main activity


Try this

INSIGHTS & CONNECTIONS

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."

VOCABULARY

cambium layer of the trunk that produces new wood cells for the tree. The cambium is only one cell thick and lies just beneath the phloem.

conifer a tree that produces seeds in cones

erosion removal of surface soil by the forces of rain and wind

heartwood innermost layer of a tree's trunk consisting of dead, tightly packed cells that provide the strength of the tree

phloem a layer of the bark of a tree's trunk that carries food downward from the leaves to the rest of the tree and roots

photosynthesis the chemical process by which green plants convert sunlight and carbon dioxide into food

resin a substance produced by some plants and trees, often used to make varnish

sapwood layer of the trunk beneath the bark that carries water and soil nutrients upward and throughout the tree

tannic acid a yellowish substance produced by redwoods and other trees, often used in tanning, dyeing, and making medicines

watershed the tributary streams of a major creek or river and its surrounding land

RESOURCES

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

MAIN ACTIVITY

How does the height of a tree in your backyard compare to that of a 65-meter (214') redwood?

MAIN ACTIVITY

  • a tree
  • ruler
  • tape measure
  • graph paper and pencil
  • twine measuring at least 100 meters (328')
  • several friends

    Questions

    TRY THIS!

    Trees send water through their trunks and out their leaves. Fill two cups with the same amount of water, mark the water levels, and tape paper covers over the cups' tops. Take two twigs, removing the leaves from one. Place one twig in each cup, poking the stems through the covers. Wrap a plastic bag around a few leaves to catch the moisture. Which cup loses the most water?

    TRY THIS!

    Water comes up through the tree's trunk and out to the leaves. Does moisture evaporate through a conifer's needles as it does through leaves of a broadleaf tree? Find out. Tie a small plastic bag over the needles of a conifer. Do the same for a broadleaf tree. Check the bags after a few hours and observe the amount of moisture in each bag.

    TRY THIS!

    Take a trip to a lumberyard. Collect various wood samples, including a piece of redwood. Interview a lumberyard employee about the desirability and availability of redwood. Finally, identify the woods and compare their characteristics. Try driving a nail through each wood sample and compare and contrast the densities of each sample.
    Newton's Apple is a production of KTCA Twin Cities Public Television. Made possible by a grant from 3M. Educational materials developed with the National Science Teachers Association.