Trees.

Background

Interesting Trees

Trees are the oldest and largest living things on Earth. The oldest living tree known is Methuselah, an almost 5,000 year old Bristlecone Pine in California. The Ginkgo is the oldest known type of tree that still exists today. They were around when dinosaurs roamed the Earth.

Trees are very important to our environment because they produce oxygen, fruit, nuts, seeds, and protection or homes for animals. We use their wood for building, paper, fuel, and other products. Tree parts are used in medicines, syrup, carpeting, rubber, cork, soap, crayons, glue, gum, and flavorings.

Every tree is unique. Trees can be identified by looking at and examining their shapes, sizes, leaves, fruits, flowers, or buds.

Types of Trees

There are two main categories of trees, broadleaf and evergreen. Broadleaf trees usually have wide, flat leaves. In areas that have cold winters, the leaves of these trees turn colors and eventually fall off. They are known as deciduous trees. When the flowers of broadleaf trees are pollinated, they develop into seeds with a hard covering (a nut) or a fleshy covering (fruit). Evergreen trees usually have long, thin leaves. These needle-shaped leaves are thick, which helps protect them from drying out during winter. Evergreens do not lose (their leaves like many other trees. Instead, they have a slow, continuous loss of leaves throughout the year. Their leaves are continuously replaced, unlike deciduous trees which only grow new leaves in spring. Some evergreen trees, called conifers, have cones instead of flowers. Evergreen seeds mature inside the cones.

Parts of Trees

A tree's roots collect water and nutrients from soil. Trees are different from other plants because they have one large, main woody stem called a trunk. The trunk supports the tree and transports water and nutrients between the roots and the leaves. The crown, which is the uppermost part of the tree, contains many branches and leaves.

The center of the trunk is made of heartwood, a strong non-living support for the tree. Surrounding the heartwood is the sapwood, made up of xylem cells. These cells carry water and nutrients from the roots to the rest of the tree. Outside this is the cambium layer, which produces new xylem and phloem cells. The phloem layer, which is outside cambium, carries food from the leaves to the rest of the tree. This layer is followed by the bark cambium, which produces new bark. The strong, outer layer of bark protects the tree from bad weather, injury, and insects. It also helps the tree to breathe. Young trees have a thin bark layer that becomes thicker with time.

Photosynthesis and Transpiration 

Photosynthesis is a process in which plants use energy from the sun to build food from carbon dioxide and water, and then release oxygen into the air. Photosynthesis provides us with most of the oxygen we need in order to breathe. Chlorophyll in the green part of leaves captures the sun's energy. Sunlight energy breaks down water into its two elements, hydrogen and oxygen. The tree or plant releases oxygen into the air. The tree or plant absorbs carbon dioxide and mixes it with hydrogen to make sugar, or food. The tree or plant makes other food substances to use or store for future use. The stored food is called sap.

People and plants are dependent on each other in sustaining life. Photosynthesis is the way plants make food for themselves.

Transpiration is the process of sucking up water and losing it again. Trees breathe in carbon dioxide and breathe out oxygen. They breathe through little holes in their leaves, or stomata. When a tree draws up water from its roots, the water is then drawn up through the tree and comes out through the stomata in its leaves.

Growth of a Tree

Trees produce huge numbers of seeds. Very few of these seeds grow into new trees. Seeds that fall in the shade of a parent tree rarely grow well, due to lack of sun. Seeds that do survive usually have moved to more hospitable environments. Some adaptations that help seeds move include: wings like miniature helicopters, cottony fluff that helps seeds float on air, and coverings on seeds like nuts and fruits. Seeds that are surrounded by fruit are frequently eaten by animals.

A young tree is called a sapling, until it reaches a height of six feet. Conifers grow fairly rapidly, but deciduous trees only grow during the period they have leaves. They have a shorter period of growth, so it takes them longer to mature.

Each year, a new layer of sapwood is formed. The amount of sapwood grown is dependent on the amount of water in a given growing season. In a dry season, sapwood will be smaller. In wet seasons, sapwood will be greater. The rings in a trunk are its layers of sapwood and by studying them, scientists called dendrochronologists (den-dro-chro-nol-o-gists), learn about the climate of the past.

LeVel Pre-A

Main Concepts: Trees are large plants. Trees provide us with many things like fruits, nuts, and wood.

Initiating Questions

1. How are trees useful?

2. What kinds of fruit grow on trees?

3. How long do trees live?

Follow-up Questions

1. What does bark do for a tree?

2. Why do trees change with the four seasons?

3. Why do people need trees? What do trees need?

Vocabulary

Answers: bee, knee, key, pea 

This activity reinforces recognition of rhyming sounds and words. Encourage students to say the words out loud to compare the sounds (example: tree, bee).

Weekly Lab

In this activity, students will guess an answer to the question, "Why do trees have bark?" Because this lab may take place outdoors, the teacher may want to select two different types of trees prior to taking the class outside. As the steps of the lab are followed, remind students to rub gently on the paper with the crayons. Students will compare the two different bark rubbings and discuss the similarities and differences of the tree bark. After completing the rubbings, students will answer the question, "Why do trees have bark?" The answer is: "Trees have bark for the same reason we have skin, to protect. It also helps trees breathe."

Math

Answers: 8 (on the left) and 3 (on the right) Circle the tree with 8 rings.

Explain to students that every year a tree's trunk will form a new ring of sapwood, and this makes it possible to see how old a tree is by looking at its stump. Students will count the rings of both stumps to determine the ages of the trees. They will compare the two and identify the oldest tree, which has the greatest number of rings.

Storytelling 

Students will study the illustrations of the four seasons and how the trees change in each picture. They will tell a story about the four seasons. Discuss with the class that there are two types of trees in the pictures. The one on the left is a deciduous tree. It changes during each season, with leaves first flowering, then becoming green and healthy, then turning color and falling off in that order, from Spring through Winter. The tree on the right is an evergreen. It stays green all year. Students will gain the knowledge that there are different types of trees.

Challenge

Students will use the alphabet and numbers to connect dots. After drawing a maple leaf and an oak leaf, students will compare the two types of leaves and understand that there are different kinds and shapes.

Bringing it Home

Students work together with a parent or family member to identify many different kinds of fruits that grow on trees. Students will cut and glue to make a collage. This activity may be done at home or in class. Using gardening catalogs or magazines helps students find more examples of fruits. Encourage students to find and use pictures of as many different varieties of tree fruits as possible (i.e., pears, bananas, oranges, apples, peaches) for comparison. Compare color, size, and shape.

Level A

Main Concepts: Trees are large plants. They provide us with many things like fruit, nuts, rubber, and wood. They are used as homes by many animals.

Initiating Questions

1. How can you tell how old a tree is?

2. What parts do trees have? What do trees need?

3. What kinds of items come from trees?

Follow-up Questions

1. How do some trees change with the seasons?

2. Why do some trees stay green all year?

3. How are water and sugar carried through leaves?

Vocabulary

Students will copy the new vocabulary words and become familiar with several different items that trees provide.

Weekly Lab

Have students collect many different types of leaves to discover the wide varieties of shape, size, and color. Through this activity, students observe that water and nutrients are carried through leaves. Students will use paint (tempera paint works best) and leaves to make leaf prints and hand prints, and then make comparisons. Ask students how the leaf prints are like the hand prints. (Possible answer: both have unique patterns and lines. Every leaf is different just as every hand is different.)

Math

Answers: 10 + 8 = 18

By counting the rings in each tree stump, students learn that trees form a new ring each year. The center is called heartwood, and the rings are sapwood. Students reinforce addition skills by adding the two numbers to find a sum.

Ask students what kinds of animals they see in the trees. Explain that trees are home to animals like squirrels and birds.

Writing in Science

Students will study the pictures of the four seasons and summarize with descriptive writing. Students will compare and contrast the two trees in the pictures and write complete sentences to explain the changes they see the trees going through. The class may have a discussion about the two types of trees: deciduous and evergreen.

Challenge

Using items that come from trees, students will recognize the variety of materials that are made from trees. They will cut, glue, and decorate to create a picture. If desired, you may provide an outline of a tree for students to fill in. Toothpicks are used as branches, nuts as blossoms, cinnamon as the trunk, cloves as flower buds, green paper as leaves, and walnuts as tree nuts. Explain that not all nuts come from trees, but walnuts and pecans do.

Bringing it Home

Using an inquiry approach, students will walk with a parent or family member to discover different kinds of trees. By writing and sketching in a notepad, students will learn attributes and names for trees.

To extend this activity, you may want to initiate a discussion about the types of trees students found and have the class create a simple bar graph with the combined data.

DID YOU KNOW?

The Oldest living tree is a Bristlecone Pine named Methuselah. It is about 4,700 Years old.

DID YOU

For every ton of Paper we recycle, 17 trees are saved.

Level B

Main Concepts: Trees are large plants that have a crown, a trunk, and roots. They are used as homes by animals and provide people with many useful products.

Initiating Questions

1. What do seeds need in order to grow?

2. How do trees change with the seasons?

3. What kinds of animals use trees for homes or food?

4. What kinds of useful products do trees give us?

Follow-up Questions

1. Why do some trees change with seasons while some don't?

2. How do trees form growth rings? Explain.

3. What special equipment do maple seeds have and why?

4. If you were in charge of the plants in your house or school, how would you take care of them?

Vocabulary

Answers: crown with king's crown and tree's crown; trunk with travel trunk and tree trunk; leaves with boy leaves and tree leaves; bark with a dog's bark and tree bark

This activity reinforces new vocabulary introduced in the text. Students are asked to apply their understanding of words by matching each word with two different meanings.

Weekly Lab By growing lima beans, students observe the growth of a seedling. Lima beans do not grow on trees but are used to demonstrate the growth process: primary root, root hairs, stem, first leaves, and first true green leaves. Students provide their seeds with water and sunlight. They use the scientific process to discover how seeds grow.

Math

Answers: 11 rings; 1994

Problem solving skills are reinforced as students count the rings (sapwood) from the outside to the center (heartwood), counting backwards from 2005.

Writing in Science

Through this exercise, students will write a full paragraph using complete sentences to describe their observations during the weekly lab. Students demonstrate understanding of how seeds grow through writing and drawing.

Challenge

See TN-Level D.

Bringing it Home

Through this activity with parental or family involvement, students learn hands-on about how long pine needles are. Metric measuring and estimating skills are reinforced. Students also identify which household items they measured come from trees.

Level C

Main Concepts: Trees have 3 main parts--a crown, trunk, and roots. There are 2 main groups of trees--broadleaf and evergreen. Trees and their parts have many uses.

Initiating Questions

1. What do seeds need in order to grow?

2. Have you ever planted anything? How long did it take to grow?

3. How are trees useful?

4. Why do some trees change with seasons while others do not?

Follow-up Questions

1. If you were in charge of the plants at your house, how would you take care of them?

2. What stages of growth do you see as seeds grow into plants?

3. Why do maple seeds have wings? What special equipment do some other tree seeds have?

4. How is water essential for living things?

Vocabulary

Answers: 1: crown; 2: trunk; 3: bark; 4: root

Students determine the meanings of the illustrations and write the word. This exercise reinforces new vocabulary as well as the understanding that words can have multiple meanings.

Weekly Lab

Students use the scientific process with an inquiry approach. Students plant and watch lima beans to learn how seedlings grow. While lima beans do not come from trees, they demonstrate the stages: primary root, root hairs, stem, leaves, first true green leaves.

Math

Answers: 12 years old; 1994; 2000

Through counting rings and calculating time, using years, students learn how to determine a tree's age. Students understand that trees form new rings, sapwood, every year. The center of the trunk is called heartwood. Problem solving skills are reinforced through completion of this multi-step problem.

Writing for Science

In this exercise, students practice journalism by gathering data and writing an article.

To extend this activity try having the class make a graph of their favorite trees. A Tree-mendous Tribune bulletin board can display student's stories.

Challenge

See TN-Level D.

DID YOU KNOW?

The oldest type of tree is the Ginkgo. They were around when dinosaurs roamed the Earth.

Students search for hidden words diagonally, horizontally, vertically, and backwards.

Vocabulary is reinforced, and students will find an answer to the question, "What are oak tree seeds called?" Answer: acorns.

DID YOU KNOW??

National Arbor Day is celebrated on the last Friday of every April.

DID YOU KNOW The Dynamite tree of Mexico has fruit that explodes when it is ripe.

Trees Level C

Did you know that trees are the oldest and largest living things on Earth?

Parts of Trees

All trees have three main parts. The crown is the top part of a tree. It has lots of leaves, branches, and twigs. The leaves are very important, because they use water, air, and sunlight to make food for the tree.

Each tree has one big, woody stem called a trunk. The trunk is very strong and tall. It keeps the crown of the tree very high, so the leaves can collect as much sunlight as possible. The trunk carries water from the roots up to the leaves. It also carries food that is made in the leaves down to the roots.

Under the ground are the tree's roots. They hold the tree in place. The roots also collect water and minerals (min-er-als) from the soil. A tree needs these things to grow.

Types of Trees

Broadleaf (broad-leaf) and evergreen (ev-er-green) are two types of trees. Broadleaf trees have wide, flat leaves. They also have flowers, fruits, and nuts. Most broadleaf trees lose all of their leaves during the cold winter months. Evergreen trees have leaves that look like needles. A few of these needles fall off all throughout the year. New ones are growing all the time, too. So, these trees stay green all year round.

Trees are used for many things. Trees are home to many animals. Wood, rubber (rub-ber), cocoa (co-coa), and maple syrup ma-ple syr-up) come from them. People and animals eat the fruit and nuts of trees, too.

DID YOU KNOW??

The oldest type of tree is the Ginkgo. They were around when dinosaurs roamed the Earth.

DID YOU KNOW??

National Arbor Day is celebrated on the last Friday of every April.

Level D

Main Concepts: Trees have 3 main parts--a crown, trunk, and roots. There are 2 main groups of trees--broadleaf and evergreen. Trees and their parts have many uses.

Initiating Questions

1. What useful things do you use every day that come from trees?

2. What types of structures do plants have? (leaves, stems, roots, flowers)

3. How do plants and trees reproduce? (pollination, seeds, etc.)

Follow-up Questions

1. How do plants feed themselves?

2. What are some necessary components of photosynthesis?

3. Why is chlorophyll important?

4. What is the role of sunlight in the process of photosynthesis? Water? Sugar?

Vocabulary

Answers: 1: leaf; 2: root; 3: trunk; 4: crown; 5: wood

While searching for hidden words, students review new words introduced on the first page.

Math

Answers: 1, 4, 2, 3 (from left to right)

By sequencing the stages of photosynthesis, students use critical thinking skills to number the pictures correctly. Students gain knowledge about the process of photosynthesis.

Weekly Lab

The lab provides an opportunity to observe chlorophyll as it is extracted from leaves.

Students make a prediction, form a hypothesis, record data, observe, and draw conclusions. Students will write a lab report in the WRITING IN SCIENCE section as they complete this lab. Before starting the lab, if faster results are desired, an adult can boil the leaves first.

Writing in Science

With the provided format, students will learn to write a lab report in full sentences.

The completed report demonstrates what the students learned from the hands-on lab experience.

Challenge

Students learn that tree seeds grow poorly if they land in the shadow of their parent tree. Through creation of a maple seed flyer, students explore how some seeds come with special equipment, such as wings, to help them move to a place where they can put down roots and grow. Some other seeds are surrounded by cottony fluff that helps them float on the air. Remind them to straighten their wings upward before launching flyers for better results. Students may experiment with different wing sizes and compare and contrast flying ability. With a partner and as a contest, students can measure distances using the metric system to compare how far the seeds fly.

Puzzle

Before solving the forest maze, the class might brainstorm the many things we use everyday that come from trees. We use wood for building, fuel, paper, furniture, pencils, etc. Tree parts are used in syrup, rubber, cork, carpeting, soap, crayons, glue, gum, and flavorings. Fruits, nuts, coffee beans, and cacao beans (from which cocoa and chocolate are made) are also products of trees. Medicines, like aspirin and the cancer-fighting drug Taxol, are derived from trees.

(See top of next page for solution to maze.)

DID YOU KNOW??

The spice, cinnamon, is made from the bark of a cinnamon tree.

Level E

Main Concepts: Trees have three distinct parts--the crown, trunk, and roots. Deciduous and evergreen are the 2 main types of trees. Trees and their parts have many uses.

Initiating Questions

1. What are two different types of trees? Compare and contrast.

2. Why do some trees lose their leaves in the fall while some do not?

3. How is water carried through a tree to keep it healthy?

Follow-up Questions

1. How would you compare your state's forests with the rest of the United States?

2. What are xylem cells and what is their purpose?

3. Explain the process of transpiration.

4. How are trees and plants necessary for all forms of life?

Vocabulary

Answers: 1: trunk; 2: root; 3: crown; 4: leaf; 5: branch; 6: bark; 7: growth ring

Students match vocabulary words to the definition or purpose.

Weekly Lab

Students use the scientific process to discover that water is carried up from the bottom of the celery stalk by xylem cells, just as it is in trees. The cells are found in bundles in the celery stalk. When stalks are checked the next day, the leaves should have a reddish color. When the stalk is broken, the xylem areas are visible as small circular, red areas. Xylem cells are located in the rings of trees. In the bonus experiment, students find moisture collected in their plastic bags. Water molecules evaporate from tree leaves, into the air, through tiny openings called stomata. This is called transpiration.

Math

Answers: Green states are Maine, New Hampshire, Vermont, and West Virginia. Brown states include Illinois, Iowa, Kansas, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, and Texas. All other states are yellow.

This map activity is an opportunity to review geography of the United States while learning how much of the country is forested. Show students a U.S. physical map, pointing out that prairie and desert states have less forested areas than other states. Including all states, the U.S. is 32.25% forested. Students color the map using their knowledge of percentages.

Writing in Science

Using the information learned in the MATH activity, students will create a graph of the data. They will think about the results in order to write what they have learned in a full paragraph. Next, students will identify their state tree and write five facts about it.

Challenge

Answers: Tree 1 began growing in 1976, was chopped down in 1999, and was 24 years old. Tree 2 began growing in 1968, was chopped down in 1995, and was 28 years old. Tree 3 began growing in 1966, was chopped down in 1987, and was 22 years old.

Puzzle

Pictures depict several useful things that come from trees. Each student will create a crossword puzzle using the grid provided to aid them. They can use a colored marker or highlighter to trace over the boxes they are using for their puzzle if it helps them. Students will number the crossword puzzle appropriately and write hints or definitions for each word. Knowledge of the material is demonstrated; and, critical thinking and problem solving skills are utilized to complete the task. Have students trade papers and solve each other's puzzles. (Example: Down: 1--a popular pancake topping made from maple trees. Answer: maple syrup. Tell students that they may use a space between the words of a phrase in a crossword puzzle or not. In published puzzles the spaces are sometimes omitted.)

DID YOU KNOW??

Many of the oldest trees in the world are in the White Mountains in California. Some are 4,500 years old.

Weekly Resources

Helpful Sources for Planning Your Science Weekly Classroom Activities

Recommended Resources

* Aronson, Steven M. L. Trees (A Fandex Family Field Guide). New York: Workman Publishing Co., 1998

* Bosveld, Jane. While a Tree Was Growing. New York: American Museum of Natural History--Workman Publishing Co., 1997

* Bulla, Robert Clyde. A Tree Is a Plant. New York: HarperCollins, 2001

* Burns, Diane L. Trees, Leaves and Bark (Take-Along Guide). Sandpoint, ID: Northwind Press, 1998

* Hickman, Pamela. Tree Book--Starting With Nature. Buffalo, NY: Kids Can Press, 1999

* Morgan, Sally. Flowers, Trees, and Fruits (Young Discoverers). New York: Houghton Mifflin Co., 2002

* Martin, Alexander and Herbert S. Zim. Trees: A Golden Guide. New York: St. Martin's Press, 2001

* Petrides, George A. Peterson First Guide: Trees. New York: Houghton Mifflin Co., 1993

Internet Resources:

http://www.idahoforests.org/kids1.htm

http://www.units.muohio.edu/dragonfly/trees.htmlx

http://www.smokeybear.com/

http://www.realtrees4kids.org/elementary/elementary.htm

National Geographic's Fantastic Forest--http://www.nationalgeographic.com/forest/html/enter.html

Forests for Our Future--http://www.forestsforourfuture.org/APPI

National Arbor Day Foundation--http://www.arborday.net/arborday/index.html and their Kids Corner--http://www.arborday.org/carly/large.htm and their Kids Make A Difference--http://www.arborday.org/programs/kidsdif.html

Tree Rings--http://vathena.arc.nasa.gov/curric/land/global/treestel.html

Tree photos and information--http://www.naturehills.com

State Trees--http://www.ibiblio.org/london/agriculture/feedback/new.links /msg00061.html

Vocabulary

Look at the pictures on the left. Write the one word on the line to the right that describes both pictures.

leaves crown --

[ILLUSTRATION OMITTED]

treasure box trunk--

[ILLUSTRATION OMITTED]

bark dog--

[ILLUSTRATION OMITTED]

cheering squad roots--

[ILLUSTRATION OMITTED]

Weekly Lab

Trees grow from seeds. How do seeds grow?

You need: 2 lima beans, a clear plastic cup, a paper towel, water, an index card

Step 1: Write a sentence on the index card about how you think seeds grow.

[ILLUSTRATION OMITTED]

Step 2: Wet the paper towel and place around the inside of your clear cup.

[ILLUSTRATION OMITTED]

Step 3: Place the lima beans between the cup and the paper towel.

[ILLUSTRATION OMITTED]

Step 4: Put your cup in a sunny place for several days.

Step 5: Watch your seeds. Twice a week, on the index card, record your observation of how your seeds change.

Step 6: What happens in a few weeks' time? On your index card, explain in full sentences whether or not your prediction was correct and why.

Keep paper towel wet. Add water every day!

Math

Every year a tree grows new wood. This wood makes a new growth ring.

1. Count the rings. How old was this tree?

2. What year did it start to grow? Count backwards from 2005.

3. During a good year, with lots of rain, the growth ring will be bigger. What year was the best growing season for this tree?

DID YOU KNOW

The spice, cinnamon is made from the bark of a cinnamon tree.

Writing In Science

As the star reporter for the "Tree-mendous Tribune" newspaper, you've been given the "tree-rriffic" assignment of writing a news story on people's ideas about trees. Interview 5 different people about their views.

Ask them:

* What is their favorite tree?

* What is their favorite tree fruit?

* What is the most unusual thing they know about trees?

DID YOU KNOW??

The largest wing thing on Earth is a Giant Sequoia tree named General Sherman.

ChallengeP

Seeds have many ways of traveling, so they can move to a good place to grow. Maple seeds use wings.

Make a Maple Flyer: 1) Cut out the flyer. 2) Fold the wings to look like the picture. Then straighten them up again. 3) Add a paper clip. 4) Now, hold your flyer high above your head and let go! 5) Stand next to a partner and both of you release your flyers at the same time. Measure how far away they land. Whose flew the farthest?

[ILLUSTRATION OMITTED]

Puzzle

What are oak tree seeds called? Complete the word find, then use the leftover letters to spell the answer.

nuts

wet

oak

broadleaf

sunlight

branches

twigs

food

water

trunk

crown

rubber

air

roots

tree

wood