Students observe leaf buds over time to see what happens as the tiny, bright green leaves burst forth.
Time Considerations
Three to four 30-minute intervals, spread out from fall or late winter to spring
Materials
- Adopted tree or other tree with branches low enough for students to observe
- Tree journals, writing utensils
- Twigs with buds (see Getting Ready)
- Plastic knives
- Sharp knife (for teacher)
- Hand lenses or magnifying boxes
- Flagging tape, colored ribbon or other marker (optional)
- Daylight Hours student page (optional)
Key Vocabulary
bloom, blossom, branch, bud, calendar, growing, leaf, pattern, season, spring, twig
Getting Ready
- Plan to conduct the first part of this activity sometime between late fall and late winter, before plants are leafing out, and then several times during the spring. You may focus the observations on your class’s adopted tree, and have students make their observations in their Adopt a Tree journals. SAFETY: Check the site for any hazards such as deep holes, sharp objects, or poisonous or irritating plants.
- Gather student journals so that they can record their data.
- Collect fallen or pruned twigs that have large buds (e.g., buckeye, hickory, poplar, rhododendron, tulip tree, some viburnums) for students to take apart. You may also collect twigs that exhibit various stages of bud development.
Doing the Activity
- Begin by asking students where they think a tree’s new leaves will come from. (They form from leaf buds.) When are leaf buds formed? (Usually the previous summer.) Are there leaf buds on the trees now? (Yes, if it’s the fall or winter.) Encourage students to share their ideas.
- Show students the twigs with large buds you have collected. Encourage children to take the buds apart, using plastic knives. Magnifying lenses will help them see the insides, or use a sharp knife to cut through a few buds and put them in magnifying boxes.
- Use a variety of collected twigs for counting, matching, and sorting. Ask: What are some things that are the same or different? Which twigs do you think came from the same kind of tree? Encourage the children to sort the twigs by the type of bud, color, or length. Ask: How did you decide what to look at when you were sorting the twigs?
- Take students outside to look closely at the branches of a tree. Hold a branch so that the students can examine the tree’s buds. Have students point out any other features they notice on the branch (bark pattern, leaf scars, buds, thorns, etc.).
- Explain to students that they are going to observe their buds over time. Have each student choose a live twig from their adopted tree to examine. Have students take notes about what their twig and its buds look like. Students should draw a picture of the twig and a close-up of one or more of its buds. You can help the students mark their twigs with flagging tape, colored ribbon, or some other marker so that they can return to the same twig each time they make their observations. Also, be sure to record the length of day for each observation day by checking the official sunrise and sunset times on the National Weather Service website.
- As spring unfolds, have students visit their buds several times and record their observations in their tree journals. Have students practice their measuring skills by helping them measure the lengths of stems and buds and record any changes. They should look for changes in the buds and any signs of animals eating the buds. Have them make notes and draw pictures of what they see. Point out that buds swell and elongate before leaves emerge.
- Ask students to compare their observed bud changes over time with the temperature and daylight data previously collected in the Adopt a Tree activity. Discuss how environmental factors, such as longer days and higher temperatures, influence tree and bud growth each spring. (Consider using collaborative discussion strategies for leading the discussion.) What would happen to the tree if the weather stayed cold or if the tree didn’t receive as much light?
- Help students use all the data they collected in their tree journals to understand observable patterns in temperature, sunlight, and tree growth. For example, you might provide students with copies of the Daylight Hours student page and show them how to use the data previously collected in their My Tree Journals to complete it. Then, challenge students to graph the data using the student page. Emphasize again the Essential Questions for Level B.
- Optional: You can “force” some trees and shrubs to flower earlier by taking cuttings indoors. Apple, forsythia, maple, oak, and pussy willow are good choices. Cut off small twigs with a sharp knife or pruner, and put them in water immediately. Change the water frequently, and recut the stem ends if needed. Compare these twigs with the trees and shrubs outside. Ask: Which do you think will open first: the buds on the twigs we brought inside or the buds on the twigs outside? Which buds do you think will be flower buds? Which buds do you think have leaves inside them? Why do you think some trees have big flowers and some trees have little flowers?
Remember to visit the Enrich tab for recommended children’s books that support the science concepts covered in this activity.
