TREE IDENTIFICATION (MODIFIED FOR ADEED)

Transcription

1 TREE IDENTIFICATION (MODIFIED FOR ADEED) Objectives: The student will: identify and illustrate characteristics of various Alaska trees. Targeted Alaska Grade Level Expectations: Science [6] SC2.1 The student demonstrates an understanding of the structure, function, behavior, development, life cycles, and diversity of living organisms by using a dichotomous key to classify animals and plants into groups using external or internal features. [6] SA1.1 The student demonstrates an understanding of the processes of science by asking questions, predicting, observing, describing, measuring, classifying, making generalizations, inferring, and communicating. Materials: Clipboards Writing paper or field notebooks Pencils or pens Small ruler Hand lens Crayons (brown, black, and green) Alaska Ecology Cards ( STUDENT INFORMATION SHEET: Task Card STUDENT INFORMATION SHEET: Forest Facts Activity Procedure: 1. Find an outdoor site where there are examples of the different trees in the area. 2. Discuss the activity. Depending on grade level, lead the children through the steps on the Science Card or ask them to complete the activity independently. 3. Students use their field notes and the Alaska Ecology Cards or a field guide to trees to identify the trees they saw. They write the name in the column Species. 4. Below the tree s name, students write one trait that will help them separate it from similar trees. Extension Idea: 1. Compile a mural of bark and leaf rubbings. Students take rubbings from the variety of local trees and leaves and create an artistic mural for the classroom or hall. Label each rubbing with the name of the tree, but conceal the name under another flap of paper. Fellow students try to guess the tree s name and lift the flap to see if they guessed correctly. Lesson Credit: This lesson adapted with permission from Alaska Department of Fish and Wildlife s Alaska s Forests and Wildlife curriculum. (2001).

2 TREE IDENTIFICATION TASK CARD Task Card Chart 1. Look at the Chart. It shows some of the different shapes and characteristics of Alaska trees and their parts. Notice the different types of tree shapes, branching arrangements, and leaf shapes. 2. Turn your notebook so that the long side of the page is facing you. Write the heading Alaska Trees along the new top edge of the page. Write these headings across the page to form columns as shown : Tree Shape Branching Leaves Twig Bark Species 3. Look at the nearest tree and fill in your Alaska Trees chart with drawings of the shape and branching of this tree. Make a crayon rubbing of the bark by holding your paper against the bark and rubbing a crayon over the top of the paper. Make a rubbing of the leaf by placing the leaf under the paper, then rubbing the crayon over it. 4. Measure the length of a leaf using a ruler and write this measurement below your crayon rubbing. Tree Shapes alternate opposite whorled Branching Patterns Conifer Leaf Shapes 5. Look at a twig at the end of a tree branch. Draw the twig. Examine it with the hand lens. Is it covered by small hairs, or is it smooth? Write hairy or smooth under your drawing of the twig. 6. Draw a line under these drawings, then find a different kind of tree and repeat Steps 3-5. Complete your chart so it includes information on all the kinds of trees in this area. Use a second page if you need it. simple leaves compound leaves Broadleaf Shapes Twigs

3 TREE LEAVES Leaves are the food factories of trees. Leaves capture light energy from the sun and gases from the atmosphere. They combine those with water pumped from the roots to make the sugars the tree uses for food. This process of making food is called photosynthesis. Skinny spruce needles and broad cottonwood leaves all work as food factories. Look at the Cross-Section A cross-section of a leaf shows several layers of cells that are organized in three systems: (1) protective, (2) food producing, and (3) transporting. 1. Protective A protective skin covers the entire leaf. It has two layers: the epidermis and the cuticle. The cuticle is a waxy layer that is usually thickest in plants growing in windy or hot, dry regions. The skin lets in light, but blocks the movement of water and gases. Little mouths or stomata in the skin on the under-side of the leaf open and close to let in carbon dioxide, release oxygen, and control the loss of water. A single leaf has many thousands of these little mouths. In most plants, the stomata open in the day for gas exchange during photosynthesis and close at night to prevent water loss. 2. Food Producing The producing system of a leaf, the mesophyll, has several layers. The palisade layer has thin-walled cylindrical cells called chloroplasts. These close packed cells contain chlorophyll, the pigment that absorbs light energy in photosynthesis. Beneath the palisade is the spongy layer which has loose-packed, irregularly shaped cells that form large air spaces. Most gas exchange oxygen (O 2 ) and carbon dioxide (CO 2 ) occurs in this area. 3. Transporting Veins transport materials to and from the leaf. The veins are tubes divided into the xylem and the phloem. The xylem carries water and minerals up from the roots. The phloem transports food produced by the leaf down to the rest of the tree.

4 ALASKA S BROADLEAF TREES Look at the leaves. If they are broad, flat leaves, the tree is a broadleaf, angiosperm, or hardwood. Broadleaf trees have flowers as well as broad, flat leaves. Flowers on a majority of Alaska s broadleaf trees are small and green and do not look like a typical flower petal. Broadleaf trees in Alaska are deciduous, losing their leaves in the fall. They become dormant as an adaptation to the cold and reduced daylight.

5 ALASKA S CONIFER TREES Look at the leaves. If the leaves look like needles or scales just picture a Christmas tree the tree is a conifer, gymnosperm, or softwood. Conifer seeds grow inside cones rather than flowers and sometimes hang on the tree for several years. The tree s crown looks like a cone as well. Since conifers typically keep their narrow, needle leaves all winter they are also called evergreens. One Alaskan conifer the tamarack is deiciduous and loses its needles each autumn.

6 Forest-related Organizations and Careers Forest science used to be relatively simple: Identify the most economically valuable tree species,assess the best timber harvest methods, and find ways to control insects. Now forest science encompasses the forest ecosystem, fisheries and wildlife biology, soil conservation, medical research, recreation planning, and climate studies just to name a few. We no longer manage and study forests by focusing on timber alone. A. USDA Forest Service (forest planning and management,wildlife biology, silviculture, hydrology, ecology, geology, forest recreation, fire management and control, plant pathology, entomology, international forestry aid, personnel, budgeting) < and < r10> for Alaska. B. Bureau of Land Management (land-use planning, wildlife biology, ecology, plant pathology, entomology, personnel, fire management and control) < and < for Alaska. C. National Park Service (park planning and management, wildlife biology, fire management, law enforcement, recreation, education) < gov> D. Alaska Department of Natural Resources (landuse planning, forest management, fire management and control) < E. Alaska Department of Fish and Game (research and management of forest wildlife) < ak.us/adfg> F. Native groups (forest management, land-use planning, environmental education, forest or natural resource law, lobbying) Contact the Alaska Native Knowledge Network s regional coordinators <www. ankn.uaf.edu> G. U.S. Geological Survey (study of forests as watersheds, research, soil science) < H. University of Alaska or other universities (research and teaching in forest ecology and management, horticulture, plant pathology, entomology, land-use planning; Institute of Northern Forestry) < I. USDA Forest Service Forest Products Laboratory (wood products research, chemistry, laboratory technology, statistics, library, computer technology) < J. The Alaska Forestry Association (represents the forest products industry) < K. Timber harvesting companies (planning, budgeting, forest engineering, surveying, logging operations, truck driving, forest or natural resource law, lobbying) (refer to Alaska Forestry Association for contacts at above web address) L. Lumber mill (mill work, mechanical operations and maintenance, management, accounting, forest or natural resource law, lobbying) (refer to Alaska Forestry Association for contacts at above web address) M. Lumber store (sales, stock handling, transportation, managers, accountants) N. Greenhouses and landscaping companies (tree and shrub horticulture) O. Conservation organizations (These groups use people with careers in biology, ecology, forestry, lobbying, natural resource law, forest conservation, resource education, natural interpretation, marketing and fund-raising) Examples include: Alaska Outdoor Council and the Alaska Fish and Wildlife Conservation Fund <www2. polarnet.com/users/outdoor> Alaska Trappers Association < paulbunyan.net/users/trappers/ata. html> National Audubon Society < org> National Wildlife Federation < The Nature Conservancy P. Tourist guiding companies ( ecotourism guides may be knowledgeable about forests, forest recreation) Alaska Wilderness Recreation and Tourism Association < Q. Occupational Handbook < describes all occupations.