At the end of the year, it is great to find something fun and relevant to use to engage your students in STEM learning. May 16th is National Love a Tree Day and you can celebrate this day by taking your students outside to count trees, measure trees, collect leaves and measure them, use your trees as a subject for art, and examine stories about trees.
If you are using Defined Learning, there are performance tasks about arborists, foresters, botanists, trees and photosynthesis, and tree-hole homes. You can also read poetry or books about trees including:
You can encourage your students to draw pictures of trees, leaves, roots, etc and/or take photographs of them.
For an interactive experience for all ages, use the “Build a Tree” activity from Sharing Nature by Joseph Cornell. This activity is best if you have 20 or more students and no supplies are required.
How to Play "Build a Tree"
How to play: Tell your students they are going to be acting out the various parts of a tree. You will build the tree one part at a time. As you proceed, you will explain the function of each tree part. The following directions are for 24 players.
1. Heartwood:
To begin, choose a tall student to come forward.
The teacher says: Christina is the tree’s inner core, the heartwood. She provides support for the trunk of the tree. Christina has been around so long that she is dead, but she is well-preserved. All her little pipelines are now clogged with resin. Ask Christina to stand tall and support the tree.
Tree fact: Heartwood is old sapwood (or xylem) that no longer transports water and minerals up the tree. The bulk of the tree trunk is its heartwood.
2. Taproot:
Next, ask a student to sit at the base of the heartwood, facing outward.
The teacher says: A taproot is a long root that anchors the tree to the earth. Miguel, I want you to be a taproot and plant yourself deep in the ground. Most trees don’t have a deep taproot, but this one does. When strong winds blow I want you to grip the earth to keep the tree from falling over. Taproots also gather water that is far underground.
Tree fact: Most trees have shallow but widespread root systems. When trees have taproots, that root usually descends less than 6 feet, although the taproots of some trees grow much deeper. How far down a tree’s roots grow depends on soil density and the presence of water, minerals, and oxygen.
3. Lateral roots:
The teacher chooses 3 students with long hair and asks them to lie on their backs with their feet toward the heartwood and their bodies extending out from the tree.
The teacher says: You are the long shallow roots called lateral roots. A tree has hundreds and hundreds of lateral roots. They grow out from the tree like branches, but underground. Lateral roots help hold the tree upright. Girls, please spread out your hair past the top of your head. At this point, the leader kneels beside one of the lateral roots and helps spread out her hair to demonstrate root hairs. Your root tips elongate and continually search for moisture. At the tips of your roots are millions of tiny root hairs that soak up water and dissolved minerals. I want both the lateral roots and the taproot to practice absorbing water. When I say “Let’s slurp!” all the roots make a slurping noise. Okay, let’s hear your slurp.
Tree fact: More than 90% of a tree’s roots live within the top 18-24 inches of soil. Lateral roots usually grow well past a tree’s foliage or drip line: there’s almost as much of the tree growing below ground as above.
4. Sapwood
Ask 3 students to encircle the heartwood and hold hands. Remind students to avoid stepping on the roots!
The teacher says: You are the part of the tree called the sapwood or xylem. You have tiny tubes that transport water and minerals up the tree from the roots to the leaves. Water is called a social molecule because water molecules stick to one another. As water molecules evaporate through holes (stomata) in the epidermis of the leaves, they draw other water molecules upward. In this way, long columns of water are drawn upward, through the sapwood. On a hot day, a large tree can move 100 gallons of water. In red oaks, water can travel at a speed of 92 feet/hour. After the roots slurp the water from the ground, your job is to bring the water up the tree. When I say “Bring the water up!” you throw your arms up and call out “Wheee!”
Let’s practice: First, the roots will slurp, then I'll tell the sapwood “Bring the water up!” and you’ll raise your arms and call out “Whee!”
Tree fact: On hot, sunny days, if evaporation (transpiration) is faster than the root's ability to keep up, to prevent water loss, the tree will take a midday siesta for several hours by temporarily closing its stomata.
5. Cambium/Phloem
Select 6 students and have them hold hands and face inward to form a circle around the sapwood.
The teacher says: This ring of students represents 2 parts of the tree: cambium and phloem. On the inside of the ring is the thin cambium layer, which is the growing part of the tree. The cambium is found in the trunk, and also, in the roots and branches. During the growing season, the cambium makes new calls that add girth to each part of the tree. Trees don’t grow upward from the base like human hairs. If someone nails a sign to a tree, that sign will stay at the same height year after year. A tree grows out from the middle and also outward from the tips of its roots and branches. The phloem is the outer side of the cambium layer, between the cambium and the outer bark. The phloem carries the food from the leaves down to the rest of the tree. Let’s turn our hands into leaves. Have the students in the circle stretch their arms upward and outward so that their arms cross the next person’s arms at the wrist, leaving their hands free to flutter like leaves. When I say “Let’s make food!” raise your arms and flutter your leaves: you are making food from the sun. When I say “Bring the food down” you go “Whooo!” (make a long descending whooo!) sound, squat down by bending your knees, and drop your arms toward the ground.
Let’s practice!
Tree fact: During spring, food made in the leaves is used for new growth; during summer, extra food is stored in the roots for the fall and winter. The cambium layer enables the trunk, branches, and roots to grow thicker. The phloem eventually turns into bark. The sapwood eventually becomes the heartwood, In temperate climates, different parts of a tree grow at different times of the year. Typically, a tree grows its foliage in spring, trunk in summer, and roots in fall and winter. In humid tropical rainforests, all the parts of a tree grow continually throughout the year.
6. Practice putting the parts together:
Use the tree’s 4 part sounds and motions in the order below and practice 2 times:
- Roots, let’s slurp.
- Leaves, let’s make food.
- Sapwood, bring the water up.
- Phloem, bring the food down.
7. Bark
All the remaining students form a circle around the tree. Everyone faces outward.
The teacher says: All of you are tree bark. Your thick skin keeps the tree safe from insects, disease, temperature extremes, and fire.The protect the tree from danger, raise your arms as would a football blocker, both elbows out and both fists close to your chest. (Pause) Can you hear that high-pitched sound, over there, in the trees? (Pause) It’s the sound of the long-snouted tree borer beetle Eatumupus Giganteus. They are big, ferocious, and always hungry. I’m going to try to stop the giant beetle from coming to eat the tree, but if I fail, it’s up to the bark to protect the tree. The teacher runs and hides behind a large tree. Using 2 sticks for antennae, he reappears as a very hungry tree borer, scowls, and eagerly approaches the tree. The tree borer runs or walks quickly around the tree and tries, at different points, to penetrate the bark’s protective layer. The bark students try to fend off the tree borer. While the teacher is going around the tree, she shouts the commands in sequence to lead the tree parts in their movements and sounds.
Repeat the whole sequence 3 or 4 times:
Heart, stand tall and strong!
Get tough bark!
Roots, let’s slurp!
Leaves, let’s make food!
Sapwood, bring the water up!
Phloem, bring the food down!
After the first round, shout the command without giving the names of the tree parts. When you finish, have the players give themselves a round of applause for being such a marvelous tree. Ask the students to help the roots up off the ground.
You may want to take a class picture in front of a tree in your location. Have fun celebrating trees!
About the author:
Dr. Cindy Moss is a nationally respected thought leader in STEM education and reform. Dr. Moss brings over 31 years of experience in district leadership, classroom instruction, and inquiry-based learning to her work as a champion for STEM engagement and career & workforce readiness. Learn more about Dr. Moss here and follow her on Twitter at @STEMboss
