FOCUS: Winter trees may look dead, but concealed in their buds are the beginnings of next year’s shoots, leaves, and flowers. Food is scarce in our winter woods, and for many animals the twigs, buds, and bark of dormant trees provide a welcome source of nutrition. Animals have no trouble recognizing which trees make the best meals, but for us identifying trees when their leaves are gone requires a close look and attention to detail, the skills of a good detective.
INTRODUCTION: TWIG QUESTIONS
Objective: To begin to explore and ask questions about trees in winter.
Ahead of time, cut twigs from a variety of trees including some that have alternate branching (e.g. elm, beech, oak, poplar) and some that have opposite branching (red maple, sugar maple, and ash). Make sure to cut twigs so they are long enough to show at least two years’ worth of growth. With maple and ash twigs, pick those that show opposite branching rather than just opposite bud scars, as these can be hard for children to see. Pass out a twig and a magnifying lens to each child. Ask them what they notice about the twigs. Also, what do they wonder about them? Make lists of their observations and questions on the board. Collect the twigs to use again later for Twig Dress-up and the journal activity.
Materials: variety of twigs showing at least two years of growth (one for each child), magnifying lenses.
A BRANCH THROUGH THE SEASONS
Objective: To model the yearly cycle of growth and change in a tree branch.
Divide the class into groups of six to eight children with an adult leader. Give each child a Branch through the Seasons card showing a stage of twig development on an American beech branch. If there are more children than cards, they can act as a “directors.” Ask the children in each group to line up in order, based on the illustrations on their cards, starting with winter. Have the lines face each other and compare to see if all agree about the correct sequence. Now demonstrate with one group how they could form a circle, since these events repeat each year. Have all groups form circles to model the ongoing cycle of growth and change in a tree branch. What are tree buds for? (They contain the beginnings of shoots, flowers, and leaves for the next growing season.)
Materials: Branch through the Seasons cards (enough sets of cards for small groups of six to eight students).
PUPPET SHOW “A Budding Detective”
Objective: To consider the importance of buds to the tree and to animals in the winter woods, and to compare the characteristics of different types of twigs.
Perform the puppet show, or have a group of children perform it for the class. Afterward, ask questions to review the key details and vocabulary in the story. Why does a tree have buds in winter? (They contain the beginning of the shoots, flowers, and leaves for the next growing season.) Why are buds and twigs important to some animals like the hare? (Food in winter.) What are some distinguishing characteristics of different winter twigs? (Thorns on hawthorn; fuzzy twigs on sumac; round, red buds on basswood; bad taste in cherry; brown twigs and pointy buds on sugar maple; alternate versus opposite branching of different twigs.)
Materials: puppets, script, stage.
Objective: To model how attention to detail helps us notice subtle differences.
Have the children choose partners, then form two lines with partners standing directly across from, and facing, each other. Explain that a good detective must be very observant and pay attention to the smallest details. Tell the children they will have a minute to observe their partner carefully, and then partners will change one thing about their appearance. Now have all the children in one line turn and face away from their partners and change one thing about their clothing, such as rolling up a sleeve, untying a shoelace, etc. It must be something visible. Now have children turn back and ask their partners to figure out what they changed. Repeat with the roles reversed. Explain that we’re going to be Twig Detectives, looking for the clues that will help us tell twigs apart. First we have to learn the names of twig parts, so we can talk about them.
Objective: To use a model to learn the parts of a twig and their functions.
Ask for a volunteer (usually the teacher) to be dressed up as a twig. Use props to represent the different parts of a twig. Give each child a twig so they can look for each part as you describe it. As you dress the teacher, point out each feature on the Parts of a Twig diagram. Include these props and terms:
- Bark: A brown or gray sweater or coat to represent bark: point out that bark can have different colors and textures and can look different when the tree is young or old.
- End (or Terminal) Bud: Paper cone hat.
- Side (or Lateral) Buds: Smaller paper cones on the hands. Have the teacher show how they can be opposite (hold both elbows at waist with hands out to the sides) or alternate (hold one elbow above the other, hands held out to the sides).
- Leaf Scars: Paper cut-outs (see Twig Dress-up patterns). This scar is left when the stem of the leaf breaks off.
- Bundle Scars: Sticky dots. These marks show where the vessels broke off when the leaf fell off the tree. They carried water and nutrients to and from the leaf.
- Bud Scales: Paper cut-outs (see Twig Dress-up patterns). These scales are protective covers on a bud, often arranged like shingles on a roof.
- Bud Scale Scars: Yarn wrapped around the waist a few times. These rings are left when the bud scales fall off and the twig extends or grows a flower or leaf. They look like the threads on a screw. They mark the beginning of each year’s growth. Have children count the years of growth visible on their twigs.
- Lenticels: Felt strips or sticky dots. Lenticels are corky areas in the bark, for gas exchange or places where the bark can expand.
Materials: costume pieces: brown or gray sweater or coat, paper cone hat, two smaller paper cone buds, paper (or felt) cut-outs from Twig Dress-up patterns, piece of yarn several feet long, sticky dots, Parts of a Twig diagram, a twig for each child or pair of children, magnifying lenses.
Objective: To record observations about the detailed structure of a twig.
Using the twigs from Twig Questions and Twig Dress-up, have the children draw their twigs in their journals, including the parts introduced during Twig Dress-up. Have the children examine their twigs closely to see how many years of growth are visible. Older children can label their drawings and/or draw and label an opposite and alternate twig for comparison.
Materials: a twig with at least two years of growth for each child, journals or paper and clipboards, pencils, magnifying lenses, Parts of a Twig diagram.
I SPY TWIGS (Grades K-2)
Objective: To review the parts of a twig and observe similarities and differences among different species.
Have children work in small groups with an adult leader. Lay out six twigs and describe one of them by saying, for example, “I spy a twig that is opposite and it has reddish buds.” Children point to the twig with those features. Continue in this manner until all of the twigs have been described and guessed, or allow students to take turns describing the twigs.
If possible, use the same kinds of twigs for I Spy Twigs that you will use outside on the playground for Find Your Tree. This way, children will already be familiar with the twigs.
Materials: twigs (enough for each small group to have a set of five or six different types of twigs), Parts of a Twig diagram.
GUESS MY TWIG (Grades 3-6)
Objective: To review the parts of a twig and observe similarities and differences among different species.
Have children work in small groups and give each team a set of five or six twigs and a paper bag. Have them lay out their set of twigs on a table or rug. Place a set of labeled twigs in a central location. Now have one child from each group come up and choose a twig from the labeled set and put it in their bag, returning to their team without revealing the twig. Group members then ask questions to try to determine which of the twigs in their set matches the one in the bag. Have teammates use the Guess My Twig Questions to find out clues about the mystery twig:
Guess My Twig Questions
Are buds opposite or alternate?
Is the twig fuzzy, smooth, fat, thin?
Are the buds pointy, rounded, fuzzy, smooth?
Is there one end bud? None? Several?
Are there lenticels (dark or light spots or lines on the twig)?
What color are the buds? What color are the twigs?
Once the group has guessed the correct twig, they may compare it to the twig in the bag. Now have a different child return the labeled twig and choose a different one to put in the bag. Repeat until all twigs have been matched. Compare twigs to those on Some Common Winter Twigs.
Optional: Consider using the same kinds of twigs for this activity that you will use outside on the playground for Find Your Tree. This way, children will already be familiar with the twigs.
Materials: a set of twigs from five or six different tree species, labeled with tree name; for each group: a set of five or six twigs that match the labeled set, Parts of a Twig diagram, Some Common Winter Twigs diagram, Guess My Twig Questions.
FIND YOUR TREE
Objective: To observe patterns of similarities and differences in trees outside and identify them by their winter twigs.
Ahead of time, mark several different trees outside with surveyor’s tape, labeled with the tree’s name. Have the children work in small groups with an adult. Give each child a twig from one of these trees (ideally the same species used for I Spy Twigs or Twig Match-up). Stop at each tree with the group and ask if anyone has a twig that matches the tree. Have them hold it up for all to see, and compare it to a branch on the living tree. Note that twigs with opposite buds also have opposite branching, and twigs with alternate buds have alternate branching. In addition, have children look at the bark color and texture and at the shape of the trees. Are there other trees of the same kind on the school grounds? How many different kinds of trees can they find?
Afterwards, as a whole group, choose a tree close to the school to mark with surveyor’s tape. Students can make regular visits to the tree to see how the twigs change throughout the year.
Materials: surveyor’s tape and marker pen to label nearby trees, twigs cut from trees on the school grounds, or from the same species of trees (enough for each small group to have a set of five or six different types of twigs).
Objective: To observe the texture of bark on different tree species and learn how bark patterns can help in tree identification.
Ahead of time, make bark rubbings from a few different types of trees in your schoolyard. Mark these trees with numbers and surveyor’s tape. In small groups, pass around the bark rubbings and have the children carefully observe them, noting the differences in patterns. Have the groups visit the marked trees and try to match the rubbings to the trees. At each tree, make (or have children make) a rubbing so the group can compare it with the originals and confirm their guesses.
Alternative: If there is little tree diversity in the school yard, make rubbings from a variety of firewood logs and bring them in to do the activity instead of with trees.
Materials: sets of rubbings from three to five trees in the schoolyard (or from firewood logs you bring along), surveyor’s tape, paper, crayons (with wrappers peeled off).
UPPER GRADES CHALLENGE: Keying out Twigs (Grades 5-6)
Objective: To use a dichotomous key to identify a winter twig.
Have students work with a partner or small group, and provide each team with a Winter Twig Key and two or three twigs to key out. Practice using the key by having everyone follow along as you key out one of the twigs (everyone with the same kind of twig). Now have the student teams try to key out the other twig(s) on their own. Were some steps more difficult than others? What accounts for this? (There is a lot of variation in twigs, even in a single species.) Have the students compare their branch to the pictures on Some Common Winter Twigs and Twig Detectives.
* Be sure that the twigs you supply are ones that are included in the key provided. This key includes some common trees in northern hardwood forests, but there are many others that are not included in order to keep it simple and manageable.
Materials: for each group: magnifying lenses, ruler, two or three twigs from those on the Winter Twig Key (including several of one species of twig so everyone can follow along as you key it out), Winter Twig Key, Some Common Winter Twigs, Twig Detectives.
Objective: To share thoughts about winter twigs.
Have children complete this sentence: “My favorite discovery about the twigs we met today was _____.”
A STEP BEYOND
Twig Relay Race: Have the children form two lines. Lay out a set of twigs on a blanket at the start of the course and a second set at the finish line. To begin, have a child from each line pick up a twig from the first set, run to the finish line, pick out a matching twig from the second set, show the pair to the “judge” (adult) to verify that it is a correct match, and then run back to tag the next child on the team. Repeat until all twigs are matched up with their twins and everyone has had a turn.