Peggy learns the amazing history of the redwoods.
Segment length: 8:29
- What are the redwoods?
- Should they be saved?
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
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
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
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
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
- 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
- What might be the problem? What are some solutions?
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
- Burnie, D. (1988) Eyewitness books: Trees. New York: Alfred A. Knopf.
- Caduto, M.J. & Bruchac, J. (1989) Keepers of the Earth: Native American stories and
environmental activities for children. Golden, CO: Fulcrum, Inc.
- 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
(membership and services)
Save the Redwood League
114 Sansome St., Room 605
San Francisco, CA 94104
National Office of Project Learning Tree
1111 19th St. NW, Suite 780
Washington, DC 20036
Local Soil Conservation Service
Local university forestry department
How does the height of a tree in your backyard compare to that of a 65-meter (214')
graph paper and pencil
twine measuring at least 100 meters (328')
- 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
- 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?
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?
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.
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