Autumn is the time of brilliance and wonder for many areas across the country as the leaves of deciduous trees burst into a vast array of colors and hues.
During the spring and summer, a substance called chlorophyll makes the leaves green so they can use the energy from the sun to make food for the tree. However, just as the chlorophyll in a green banana breaks down and reveals the hidden yellow color, so do the leaves on deciduous trees as the days become shorter and the temperatures become cooler. Yellow, orange, red, and even purple pigments begin to emerge as the chlorophyll slowly begins to fade.
There are numerous reasons to account for the array of colors in the leaves of a tree. On warm, cloudy and rainy days in the fall, there tends to be less red in the leaves. Trees that are more in shady areas tend to be yellow, while those in the sun are more brilliant shades of red.
Deciduous trees prepare for winter in another way, as well. Trees give off a lot of water through their leaves through a process called transpiration. Since trees can’t take in as much water on cold, wintry days, they drop their leaves to prevent dehydration. As autumn begins, the leaves send their sugars to be stored and a cork layer forms where the leaf is attached to the tree to seal the separation of the leaf from its supporting tissues. Eventually the leaves are blown off by the wind or fall from their own weight and a leaf scar is left behind.
Objective: To provide students with the opportunity to document the changes of the leaves of local deciduous trees in the fall.
Use the Treeture, Autumn, as a guide, icon or symbol to help animate and enhance your leaf lesson. Autumn is a Leaf Turner who helps the leaves turn colors in the fall.
Begin by brainstorming any signs in nature that signal the change of summer to fall. Read the book, Time To Sleep by Denise Fleming and chart the changes of seasons mentioned in the story. Use the background information in this lesson to discuss the preparations that deciduous trees make to prepare for winter. (A further experiment to observe chlorophyll in the leaves of a tree can be found under "Chlorophyll" on the Treeture web site.)
In your Science Journals, predict the date that Autumn will make her first changes of leaf color in your area.
Take Autumn out on a walk with you to identify the types of trees on or around your school campus using a Tree Identification Guide. Number the trees for easy reference. Divide your students into teams and assign each one a tree. Have groups monitor their tree on a daily basis and chart the following:
Have the students compare their findings to see which types of trees changed colors first/last, which changed the most quickly/slowly, and what colors the different species of trees displayed. For a guide to the colors different trees most often display, visit the following web site: http://www.10000inns.com/fall_foliage/leaves_color.htm
*The Treeture characters, as learning tools, can be adapted to any grade level. For example, students in grades K-1 could utilize coloring pages, finger puppets, and collages. Stories, poems, creation of new Treeture characters, newsletters, and plays could be fun and used as mentoring projects by 5th and 6th graders for younger students. Another entertaining and educational activity is to hold a Treeture Fair. This project has been successfully implemented in several schools. Each Treeture character can be enlarged and placed on an easel on a table with an appropriate experiment or example of its tree role.
Totally True Treeture Trivia:
The shaded side of a tree loses 25% less water than the sunny side.