Photo of Natchez Trace, National Park Service (http://www.nps.gov/natr/planyourvisit/fall-colors.htm)

Fall Color Activities

Based on Why Leaves Change Colors (Purdue Extension, YSS-1, out of print)

2015

Fall Color Activities Introduction The activities in this document are intended to teach youth about plant and tree biology. We suggest that this package be used in the fall of the year. Several of the activities provided are best suited for use when the leaves are changing their colors. The activities can be used in a classroom, workshop, camp setting, or 4-H club. You can decide how you want to use the activities and which ones will work best for your learners. Audience Target audience: youth in grades 3 - 8 Instructions Select the ones work best for your situation and the age, or age range, of the youth. Older youth may prefer to help with the organizing and teaching. The first six activities introduce leaf differences and biological processes. Activities 4 and 7 introduces the biology of leaf color change. Science Standards 1) Structure, function, and information processing (elementary school; middle school if cellular

changes are discusses) a) Key words: leaves, color

Author: Bill Chaney Department of Forestry and Natural Resources, 1999 Editor: Randy Spears, Agricultural Communication, 1999 Revisions: Natalie Carroll, 2015 Contents: Activity 1. Leaf Comparisons Activity 2. Nature Walk Activity 3. Sunlight and Chlorophyll Activity 4. Anthocyanin Pigments in Leaves, and Beets Activity 5. Tree Color Tour Activity 6. Trading Leaves Activity 7. Why Leaves Change Color

Activity 1. Leaf Comparisons This activity should be done cooperatively with younger (elementary aged) youth. Older youth (middle school) may have more fun completing the activities as a relay race. Divide the group into teams of 3 to 4. Give each group a plastic bag and ask them to collect 20 leaves. They should try to get leaves from several different kinds of trees and collect leaves with different shapes and colors. Leaves may be picked from the ground or from low hanging branches. Give the youth a time limit to collect the leaves (10 or 15 minutes should be plenty of time). Each team then places their bag of leaves on the floor or a table. They need to be able to sit closely enough to reach the leaves. 1) Color Matching

a) Give each team five small pieces of colored construction paper: yellow, red, purple, green, and brown.

b) Ask the youth to sort the leaves they collected into piles that most closely match each of the colors on the construction paper.

c) Each team should count how many leaves they have of each color and enter their values in a table on a board or large Post-it pad.

d) Compare and contrast the totals for each color. e) Relay race: place each team’s leaf pile away

from the ‘start’ and have youth take turns running to their pile; sorting out one color; counting as they return that color of leaves to the plastic bag; entering the value in the chart; and returning to their team before the next team member starts. Some youth will make two trips to their leaf pile. They must take turns entering the data even when there are ‘0’ leaves of any color. The team that finishes first presents their leaves and justifies the color selections they made by showing each leaf and placing it in the appropriate color pile. If they made a mistake, they must be disqualified and the second place team shows their leaves and justifies their selections.

2) Tree Identification a) This activity requires copies of the center page from the booklet, Fifty Trees of Indiana

(4-H-15-80, by T.E. Shaw) for each team. Elementary youth may need the help of a middle or high school student to complete this activity.

b) Show the group the center of the book showing the taxonomy key. Explain that leaves are arranged (attached to a twig) in one of two ways: “Alternate” or “Opposite.” Page 9 of the reference book shows the difference and other important differences used to identify leaves that can be discussed if you are working with older youth.

Team Yellow Red Purple Green Brown1234

Totals

c) Have the teams work together to identify 10 of their leaves using the leaf arrangement and the pictures in the taxonomy key. Older youth can use the additional information to more accurately identify their leaves.

d) Relay race: see which team can correctly identify their leaves the fastest. If you are not comfortable with assessing their ID’s, many Ag and Natural Resource Extension Educators or an IDNR District Forester (see www.in.gov/dnr/forestry/files/fo-District_forester_list_print_version.pdf) may be able to assist you.

3) Leaf Outlines and Veins a) Have each team member chose two of their favorite leaf shapes from the leaves they

collected. They cannot share a leaf. b) Youth then place a sheet of white paper (20# or lighter) over the two leaves and rub the

with a pencil, crayons, or markers to show the leaf outlines and veining. c) Ask youth to compare and contrast their outlines with their teammates d) Hold a general discussion with all the teams

4) Relay race: after the youth have outlined their leaves, place each team’s leaves back in the plastic bag with their leaf outlines on top of the bag at one end of the room or at a set distance (if outside). Teams line up in front of their leaves and (when organized) move one bag to the right (or to the other end, in the case of the team that is on the far right). At the “start” signal, team members must take turns to take one sheet of paper and locate the two leaves that were outlined. They return to the line with the leaves and the outlines and the next team member does the same until all the leaves that were traced are found. Adjustments will be needed if teams have different numbers of team members to assure that all teams must find the same number of leaves.

Activity 2. Nature Walk: Signs of Autumn This activity requires a wooded area and focuses on observation skills. Begin the activity by asking the group the questions below and recording their answers on a board or large Post-it pad. Then, take a walk through a wooded area containing both deciduous and evergreen trees. Ask the youth to observe as much as they can to help them answer the questions more accurately. Return to the classroom/outdoor lab and discuss each question again. See how much detail the youth can add. Questions:

1. How many different colors can you find in nature? What are they? 2. What different leaf colors do you see on trees? What do you see most? Second most? (Or,

what percentage of each color do you see?) 3. Are all the leaves on a tree the same color? 4. How are deciduous (trees that lose their leaves in the fall) and evergreen trees different? 5. Do leaves fall from all trees at the same time? 6. What happens to the leaves and needles that fall from trees? Does it matter where they

fall (park, city, woods, school, home)?

Activity 3. Sunlight and Chlorophyll This activity shows how chlorophyll needs sunlight to continue to produce the green coloration that is commonly seen all summer. It takes a few days (at least four to five) to see a change so will need to be set up ahead of time if the youth you are working with do not meet two weeks in a row. Do not do this activity if rain is expected. The instructions are given for classrooms or meetings that are about a week apart.

1. Have each student cut out a sunblock in the shape of a circle, square, or even their own name (in block letters) from lightweight cardboard or construction paper. The size of the sunblock should be about so it will cover about 1.5 x 1.5 inches2.

2. Select trees with low hanging branches and leaves that youth can easily reach. 3. Have each person find a leaf that is in direct sunlight and at least twice as big as their

sunblock and attach the sunblock to the leaf. a. Use two paper clips to attach the sunblock to the leaf surface that is towards the

sun. b. You may prefer to demonstrate this at the first meeting and ask the youth to do

this on a tree at their own home so they can observe the changes each day. They should not disturb the sunblock, rather observe from below. They should bring the leaf to the follow-up class, with the sunblock still attached.

4. Remove the sunblock after four to seven days. 5. Compare and discuss the effect of the sunblock on the leaf.

a. Explain that leaves need sunlight to produce chlorophyll* and remain green. Chlorophyll is a leaf pigment that serves as a photoreceptor, or light receiver, for the tree. Chlorophyll must be made constantly by the tree because continued exposure to sunlight destroys this pigment.

b. Ask if students have observed a similar color change in grass. (This change will also occur when grass is covered for a few days and can be shown by leaving a piece of wood or other flat object on the grass during this experiment.)

Activity 4. Anthocyanin Pigments in Leaves, and Beets This activity shows how the pigment anthocyanin, found in some deciduous trees, flowers, and beets can cause red coloration. You may want to do step 1 up to a day ahead of time to show that this pigment is not released by the leaf (or beet) until it is cut.

1. Place 3-5 undamaged leaves with red fall color and an entire beet in different bowls or jars of water.

a. There will be little (perhaps no) color change in the water after several hours to a day.

b. The pigment anthocyanin has not been released. 2. Cut the leaves and the beet into slices with a knife and place them back in the bowls/jars. 3. Some red coloration should color the water as the anthocyanin pigment escapes from the

damaged cells. 4. Boiling the leaf slices and beet slices in different pots to further enhance the release of

pigments as more cells are damaged. 5. Discuss these color changes. Additional information (use as appropriate):

a. The red, pink, and purple colors in leaves are created by anthocyanin and influenced by pH.

b. Fall weather conditions affect anthocyanins more than the other pigments. Shades of yellow and brown will always appear but warm sunny days followed by cool (not freezing) nights are favored for the formation of bright red autumn colors.

c. Anthocyanins are in a class of pigments known as flavonoids. Flavonoids are found in a variety of plants and in a variety of colors, and they are the substances that give flowers and fruits their hues. Flavonoids are thought to be important in attracting birds, insects, and mammals to the plant for pollination.

d. Anthocyanins are not usually present in leaves until autumn. e. Some trees, such as the Norway maple, have such high levels of anthocyanins

causing the trees to have a red or purple leaves throughout the summer. f. Not all trees have the genes required to produce anthocyanin, however. Ash and

oak, for example, have no anthocyanin, and tum bright yellow in autumn. g. Trees that have more anthocyanins, such as red maple, sugar maple, sumac,

sassafras, scarlet oak, and winged euonymus can produce spectacular displays of red and crimson.

Activity 5. Tree Color Tour Divide the group into teams of 3 to 4. Each team will make a video recording to guide other through a short tour of 10 trees to teach about fall leaf color. The team should work together to plan their video and choose the trees they will show before they begin taping. The team should decide what their primary focus will be. They can focus on one fall color (e.g., red or yellow), many colors, different types of trees, different aged trees or any other variable that they are interested in. This activity could be done by middle or high school youth to make a recording for elementary youth. Recordings should include the following.

1. Team introductions – Who are they? 2. Start location – Where does the tree color tour start? 3. Directions to the first tree – Directions can be given using land- marks, compass

directions, or distances as measured in steps (sized to the target audience). 4. Tree description – Describe tree size, general shape, bark, and leaf color (s).

a. Optional: older youth who have completed activity 7 (Why Leaves Change Color) should include the pigment (cause of the color).

5. Directions to the next tree – repeat step 4 for each of the 9 remaining trees. Once the videotaping is complete, teams can share and analyze each team’s work and suggest improvements. They can then be shared with other friends, parents, or younger audiences. The video tape process could be repeated during other seasons (winter, spring, and summer) to show how these trees change throughout the year. Comparing the same tour over multiple years, particularly in the fall, while time consuming, will show how weather conditions affect fall colors.

Activity 6. Trading Leaves This activity requires finding an educator in a different part of the country willing to supply leaves common to their area. This activity will be more effective if you can find a source outside the Eastern Deciduous Forest habitat (shown by the light blue in the map shown below). The leaves should be attached to sheets of paper with transparent tape to keep them flat for mailing. Choose one, or all, of the Activity 1. Leaf Comparisons topics (Color Matching, Tree Identification, Leaf Outlines and Veins) to help youth understand how trees can be different from those we find in Indiana. A discussion about how weather and climate effects plants and animals will help youth understand 1) why there are differences and 2) how they might learn to identify a location in a picture by understanding the trees that grow there. See the Level 1, Weather and Climate Science manual (4-H-1023. Available at Purdue University’s The Education Store, www.edustore.purdue.edu)

Activity 7. Why Leaves Change Color This activity includes scientific names and more complex biological processes so is most appropriate for middle and high school youth.

1. Divide youth into teams of 2-3

2. Give each team a copy of the Why Do Leaves Change Color text and graphic from Appendix A of this booklet

3. Have each team work together to complete: o Read the information provided. o Complete one of the matching handouts given in Appendix B (2 options) using

the information they read together.

4. Answer keys are given in Appendix C (and below).

Glossary Anthocyanin- complex pigment that ranges in color from red to blue which is dissolved in the

cell sap inside the vacuole of plant cells. Carotene- yellow-to-orange pigment located in the plastids of plant cells. Chlorophyll- green pigment located in the chloroplasts in leaves that can

capture the energy from the sun and is essential for the process of photosynthesis.

Deciduous- growth habit in which leaves fall from trees each autumn. Glucose- a basic six-carbon sugar that is a product of the process of

photosynthesis. Photosynthesis- the production of sugars and oxygen in plants from carbon dioxide and water in

the presence of chlorophyll using the energy from the sun. Tannin- substance dissolved in the cell sap inside the vacuole of plant cells that imparts a brown

color to leaves, bark, and some fruits. Notes _______________________________

Appendix A. Why Leaves Change Color Why Do Leaves Change Colors? Deciduous trees shed their leaves each year after capturing important nutrients from them and become dormant rather than risking loosing these nutrients during winter. Shedding leaves also allows deciduous trees to replace damaged leaves. Fragile leaves are often are damaged by insects, diseases, or weather during the summer. Thin leaves are easily damaged by freezing. Replacing the leaves each spring allows the tree to start fresh each year with a set of undamaged light collectors. Growing New Leaves Tree store nitrogen from leaves in twigs and branches over the winter. They use this nitrogen in the spring to make amino acids. Amino acids are the building blocks of proteins and are required to make new tissue including new leaves. Some of the nitrogen also will be used to create new chlorophyll. Biology of Leaf Drop Deciduous trees begins breaking down chlorophyll in the leaves and moving the sugars and starches into storage cells in the twigs in the autumn in response to environmental changes (day length, light quality, and temperature). The nitrogen in the chlorophyll also is moved into storage cells. Nitrogen is valuable to plants, and each chlorophyll molecule contains four atoms of it. So, rather than let that nitrogen just fall to the ground with the leaves the tree takes it to the twigs and then sheds the leaf. Once the leaf is drained of its chlorophyll, the tree begins a process that removes the leaf. Trees release two hormones during the growing season: auxin and ethylene. When auxin levels are high, leaves stay attached to the trees. When fall approaches auxin levels drop and ethylene begins to affect a thin layer of cells near the base of the leaf (the abscission zone). This causes the production of enzymes that dissolve the polysacchmide (“glue") that holds the cells together. Once the polysacchmide is dissolved, the cells in the abscission zone to separate and the leaf to drop to the ground. Many people call leaf drop “falling” but scientists often refer to it as “shedding.” Favorable Conditions For the best color show, bright sunny days and cool nights are needed. The clear days allow photosynthesis to continue and allow the maximum production of anthocyanin. The cooler temperatures of autumn decrease the loss of nutrients, such as carbohydrates, through respiration and allow the pigments to accumulate. Leaf colors can vary because of differences in the amounts of soluble sugars in the leaves. Trees exposed to the sun may continue photosynthesis and turn red while others in the shade may be yellow. A single tree may have different colored leaves due to one leaf shading another. A mild or moderate drought will also increase the brilliance of the reds of autumn by stimulating anthocyanin production.

Leaf Pigments and Seasonal Changes Chlorophyll – Green & Overpowering The green in the leaves from May to October is created by a pigment called chlorophyll. Chlorophyll absorbs the radiant energy of the sun and is essential for photosynthesis – the conversion of carbon dioxide (CO2) and water (H2O) into sugars and starches necessary for tree growth. Chlorophyll serves as a photoreceptor, or light receiver, for the tree. Chlorophyll must be made constantly by the tree because continued exposure to sunlight destroys this pigment. As temperatures begin to drop in the late summer, trees prepare for winter by stopping the production of chlorophyll. The chlorophyll already present in the leaves begins breaking down into simpler compounds, which are stored for the winter in the tree's twigs. As the chlorophyll is broken down, other colors -- the familiar yellow, orange, red, and purple colors of autumn -- are unmasked. Carotenoids – yellow-orange The yellow-orange colors in leaves in the autumn are caused by pigments known as carotenoids. This pigment also gives the characteristic orange color to carrots. Carotenoids work in conjunction with chlorophyll by capturing sunlight and quickly transferring the energy they receive to chlorophyll. They assist by capturing different wavelengths of light, and also by guarding chlorophyll from receiving excessive solar energy. Carotenoids are not visible during the summer because there is more green chlorophyll. We begin to see the yellowish colors when a tree reduces the production of chlorophyll. Trees with brilliant displays of yellow in the autumn include the Norway maple, Ohio buckeye, yellow poplar, sycamore, birches, hickories, ashes, beech, honey locust, and ginkgo trees. The same process accounts for the yellowing of leaves due to nutrient deficiency or a disease that reduces the production of chlorophyll. Anthocyanin (Flavonoids) - Red The red, pink, and purple colors in leaves are created by anthocyanin and influenced by pH. Fall weather conditions affect anthocyanins more than the other pigments. Shades of yellow and brown will always appear but warm sunny days followed by cool (not freezing) nights are favored for the formation of bright red autumn colors. Anthocyanins are in a class of pigments known as flavonoids. Flavonoids are found in a variety of plants and in a variety of colors, and they are the substances that give flowers and fruits their hues. Flavonoids are thought to be important in attracting birds, insects, and mammals to the plant for pollination. Anthocyanins are not usually present in leaves until autumn. Some trees, such as the Norway maple, have such high levels of anthocyanins that the trees have a red or purple leaves throughout the summer. Not all trees have the genes required to produce anthocyanin, however. Ash and oak, for example, have no anthocyanin, and tum bright yellow in autumn. Trees that have more anthocyanins, such as red maple, sugar maple, sumac, sassafras, scarlet oak, and winged euonymus can produce spectacular displays of red and crimson. Tannins – brown Tannins cause the brown hues of trees in the autumn. They are always present in leaves, as with the other pigments, but only become visible when the chlorophyll and carotenoids are no longer being produced. Tannins are the pigment that causes the color and flavor of teas.

Appendix B. Why Leaves Change Color Activity Sheet Read Appendix A. Why Leaves Change Color and review the graphic provided. Then cut out the pigments and “callouts” below and match each callout with the pigment that describes it best.

Draw a line from each text cell to the pigment that it best describes.

Guards chlorophyll from receiving sunlight

In a class of pigments known as flavonoids

Creates reds, pinks, and purple in leaves

Not all trees have the genes required to produce this pigment.

Not usually present in leaves until autumn

Cause the brown hues of trees in the autumn

Examples: Ohio buckeye, yellow poplar, sycamore, birches

Pigment that causes the color and flavor of teas

Absorbs radiant energy from the sun

Sunlight destroys this pigment

Appendix C. Why Leaves Change Color Keys