Topic: Structure and Function of Tree Parts

Time: One class period

Illinois Learning Standards:

Applications of Learning:
*Communicating by expressing and interpreting information and ideas.
*Working on Teams by learning and contributing productively as individuals and as members of groups.
*Making Connections by recognizing and applying connections of important information and ideas within and among   learning areas.

4A.  Listen effectively in formal and informal situations.
4B.  Speak effectively using language appropriate to the situation and audience.
5C.  Apply acquired information, concepts and ideas to communicate in a variety of formats.
12A. Know and apply concepts that explain how living things function, adapt and change.
12B. Know and apply concepts that describe how living things interact with each other and with their environment.
25A. Understand the sensory elements, organizational principles and expressive qualities of the arts.
26B. Apply skills and knowledge necessary to create and perform in one or more of the arts.


Benchmarks:
Early Elementary
Late Elementary

Source:
Adapted from Naturescope: Trees Are Terrific!, National Wildlife Federation
Adaptation by Don Nelson, Western Illinois University

Objectives:
1. Learn the parts of a tree.
2. Explain how each part works.
3. Work together as a human model of a tree.
4. Act out the major function(s) of tree parts.

Vocabulary:
Heartwood - inner core of dead wood that supports the tree.

Sapwood (xylem tubes, part of inner bark)- the youngest layer of wood that transports water and minerals up the tree.

Cambium (part of inner bark) the growing layer that is only one-two cells thick. It makes new cells during the growing season that become part of the phloem, part of the xylem, or more cambium.

Phloem (part of inner bark) - the food supply line that carries sap (water containing dissolved nutrients and sugar) from leaves to branches, trunk, and roots and in the spring brings the sap back up to the tree parts.

Outer Bark - protects the tree from injury and disease.

Taproot - long main root that anchors the tree and absorbs water and nutrients from deep in the soil. It also helps support the tree.

Lateral Roots - underground branches that get smaller and smaller. They take in water and nutrients from every square cm of soil in the area under the tree. They are also part of the support system.

Materials/Procedure:
one slip of paper per student
chalkboard or easel paper showing diagram of tree parts layers ( p. 10 , Trees Are Terrific!)

1. Name the slips of paper as follows. The numbers are suggested for a class of 24 and can be modified for other class sizes.    Heartwood (1), Taproot (1), Lateral Roots (2), Sapwood (Xylem) (2), Cambium (4), Phloem (8), Outer Bark (6).   Each student draws a tree part to act out.

2. Take them to an open area preferably outside.

3. HEARTWOOD (1)
*Cross arms and stand in the center of the area. Or, if more than one, stand back to back and link arms.
*You are the heartwood, the inner core, the backbone of the tree! You hold the trunk and branches upright so the leaves can spread out to get the most sun. You used to be alive, but your thousands of xylem tubes that used to carry water up and phloem tubes that used to carry food down to the other parts of the tree are now clogged with resin and pitch.
*Stand tall and strong!

4. TAPROOT (1)
*Sit at the base of the heartwood facing outward.
*You are the biggest and longest root and are called the taproot. You go down about 4-8 meters (15-30 ft) so you can get water for the tree as well as hold it up. Not all trees have a taproot (redwood), but this one does.
*When I say, "Let's slurp!", you go like this (make loud slurping sounds). You're drinking for the tree.

5. LATERAL ROOTS (2)
*Lie on your backs with your feet against the trunk extending your body away from the tree.
*You are the lateral roots, hundreds of them. You grow outward all around the tree, like branches only underground. You also help hold up the tree. At your tips are tiny root hairs (spread out the hair of one of the lateral roots). Trees have root hairs in every square cm of soil for a long distance from the trunk. They suck up water and nutrients and their tips have cells as tough as football helmets.
*When I say "Let's slurp!", you all go like this (make slurping noises). Let's slurp!

6. SAPWOOD (2)
*Face the heartwood and join hands.
*You are the sapwood (xylem tubes). You draw water up from the roots and lift it to the highest branches. You act like a pump, but have no moving parts. You lift hundreds of gallons of water each day at faster than 100 miles per hour (60 kilometers per hour). The roots will draw the water from the ground and your tubes carry it up the tree.
*When I say "Bring the water up!" you go "Wheee!" and draw your hands up into the air as you get the water from the roots. Let's practice. "Let's slurp!"     "Bring the water up!"     "Wheee!"

7. CAMBIUM (4)
*Hold hands and form a circle facing the sapwood (xylem). Now link arms, if possible.
*You are the cambium layer which is only one or two cells thick, the growing part of the tree. Every year you add a new layer to the sapwood and phloem (inner bark)The trunk branches, and roots grow thicker and longer.
*Chant "We make new cells; we make new cells; we make new cells!"

8. PHLOEM (8)
*Form one or two circles around the cambium layer facing them.
*The phloem carries food that is being made by the leaves to all the other parts of the tree.
*Raise your arms upward and outward so your wrists or forearms touch those of your neighbors leaving your hands and fingers free to flutter like leaves. When I say "Let's make food." raise your arms and flutter your leaves to absorb energy from the sun and make food. When I say "Bring the food down!" you go "Whooo!" (a long sound with the pitch going down like this - demonstrate). You bend your knees and drop your arms and body toward the ground. Let's practice!

Let's slurp!
Let's make food!
Bring the water up!
Bring the food down!

Note: Cambium is chanting in the background. Phloem makes food before sapwood brings the water up. Arms should be down until you say "Let's make food!" so they won't get tired.

9. OUTER BARK (6)
*Form a circle around the tree facing away from the heartwood.
*You are the outer bark. From what dangers could you protect the tree? If they don't, suggest fire, insects, extreme temperatures, people with pocket knives, or dogs.
*Cross your arms across your chest like a football blocker, elbows out and fists close to your chest.
(pause) Do you hear that low pitched sound? (pause) It's a very hungry long snouted pine-borer. I'll go see if I can stop it! If I don't come back, you'll have to take care of the tree.

10. FINAL ACTION
Disappear behind a tree and come out as a pine-borer. Ham it up! Zero in with your antennae and point your long snout toward the tree. Now walk quickly around the tree pretending to try and penetrate the bark's protection. The bark should try to fend you off. While you are going around the tree, lead the rest of the tree groups in their parts. Shout the commands for all the groups in sequence: (First time only!) "Heartwood, stand tall and strong!" and "Get tough bark!"

1. Roots, let's slurp!"
2. "Leaves, let's make food!"
3. "Sapwood, bring the water up!"
4. "Phloem, bring the food down!"

Give yourselves a big hand!

Function is the job done by each part of the tree. The parts give the tree structure and the parts function in a system that gives life to the tree. Tell your function when I call out your name:
1. Heartwood - structure and balance
2. Taproot - water and nutrients, structure and balance
3. Lateral Roots - water and nutrients, structure and balance
4. Sapwood - get water to tree parts
5. Cambium - make new cells
6. Phloem - bring food to tree parts
7. Bark - protect the tree system

ASSESSMENT IDEA: Build a tree model and describe parts and function in the system.