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Tree Identification - Natural Walk

Keywords: Dendrology, tree identification; Grade Level: grades 5-6; Total Time Required: Five 35-minute class periods; Setting: Classroom and Outdoors (Yellow Creek State Park); Subjects Covered: Environmental Science; Topics Covered: Dendrology or Tree Identification

Goals/Objectives for the Lesson

•    Students will be able to define dendrology as the science of tree identification.
•    Students will recognize coniferous and deciduous trees.
•    Students will be able to distinguish the difference between a simple and compound leaf.
•    Students will be able to identify the difference between a leaf and leaflet by locating the bud.
•    Students will observe the three leaf types: scale-like, needles, broad & flat.
•    Students will observe leaf arrangements: opposite, alternate, whorled.
•    Students will observe leaf margins: entire, serrate, lobed, dentate, double serrate.
•    Student will identify common trees of Pennsylvania using dichotomous key and tree identification field guides.
•    As students acquire information about Penn’s Woods, hopefully, they will develop an appreciation for the forests and become a forest steward.

Materials Needed

•    Summer Key for Pennsylvania Trees
•    Tree Finder field guides
•    Introduction to Forest Management and Silviculture PowerPoint
•    PA Tree ID PowerPoint
•    Sample branches taken from trees that will be observed on nature walk

State Standards Addressed: Science and Technology - Biological Science 3.3.7A

Teaching Model: Direct instruction, Cooperative learning groups

Methods/Procedures

Use Introduction to Forest Management and Silviculture PowerPoint from Forest Resource Institute for Teacher - June 2009 (Slides 29-30).  Ask the group…Is it possible that these trees are the same age?  Clear up the misconception that larger trees are always older trees by discussing the following key points:

  • The trees in the slide are the same age but show very different diameters.
  • Smaller diameter trees are not necessarily younger trees.
  • Smaller trees may be slow-growing species.
  • The growth of smaller trees may have been affected by such factors as genetics, the amount of sunlight, nutrients, water, etc.
  • Narrow growth rings indicate that other trees shaded the young tree, depriving it of sunlight and moisture.

Introduce the term dendrology, the science of tree identification, using Trees + Me = Forestry, pp. 10-17.

In preparation for a field trip to Yellow Creek State Park which involves a nature walk, use PA Tree ID PowerPoint from FRIT - June 2009 in conjunction with Summer Key for Pennsylvania Trees (pp. 16-17 of Trees + Me = Forestry also contains a condensed version) which may be obtained from the local Cooperative Extension office.  Introduce and review:
•    Coniferous trees – bearing cones; needleleaf trees; evergreen; softwoods because most of them have softer wood than broadleaf trees (firs, hemlocks, pines, spruces)
•    Deciduous trees – shedding leaves each year; broadleaf; hardwoods because trees such as beeches, maples, and oaks are tough, hard wood that makes excellent furniture (maple, elm, oak, walnut, willow, ash)

Using Summer Key for Pennsylvania Trees, Tree Finder field guides, and  sample branches of common Pennsylvania trees illustrate and discuss:
•    the difference between a simple and compound leaf
•    the difference between a leaf and leaflet by locating the bud
•    the three leaf types: scale-like, needles, broad & flat
•    the difference between pinnately compound and palmately compound
•    leaf arrangements: opposite, alternate, whorled
•    leaf margins: entire, serrate, lobed, dentate, double serrate

Allow students several days of class time to completely discuss and review PA Tree ID PowerPoint together.  Permit students to take home Summer Key for Pennsylvania Trees and Tree Finder field guides.  Encourage students to explore their yards and the wooded areas around their homes.  As students bring in samples of tree branches, work together in groups cooperatively identifying each example.

Evaluation

During the nature walk, groups of students will identify trees along the nature trail using Summer Key for Pennsylvania Trees and Tree Finder field guides.  After the field trip to Yellow Creek State Park, students will work together in groups to identify the samples gathered on the nature walk and samples brought in from their neighborhoods.  Displays on tables or bulletin boards may be created by each group to exhibit their findings; students would clearly label their samples.

Options to differentiate instruction according to student abilities
•    During nature walk, discuss and direct students to examples of shade tolerant species, such as beech, sugar maple, dogwood, hemlock.  Present examples of intermediate species that tolerate a little of both sun and shade: red maple, oaks, white pine, yellow birch.  Intolerant species, such as aspen, black cherry, ash, hickory, and yellow poplar need full sun.
•    Discuss regeneration. Regeneration - to grow again; to form a new part to replace what is lost.  The regeneration of forests can occur through seed dispersal (Review ways that seed can be dispersed.), stump sprout, root suckers, and artificial means such as tree farming.
•    As an extension of this concept, students would identify the state trees of all fifty states in the United States.  They would then determine if each state tree was a broadleaf, needleleaf or palm tree. To incorporate math, students could then calculate the total number of trees of each type. They would then determine the percentage of state trees that are broadleaf, needleleaf and palm. (There are 29 states that use broadleaf trees, 19 states that use needleleaf trees, and 2 states that use palm trees.)
•    Reinforce the term opposite. Use “MAD Horse” to remember that the maple, ash, dogwood, and horse chestnut are opposite branching.  They are the only native trees in our region whose limbs, branches, and leaves grow opposite each other.

Literature/Sources Cited

Debnam, Betty (1989). The Mini Page. Indiana Gazette.

Hansen, Robert S., and James C. Finley (1996). Trees + Me = Forestry Adapted. University Park, Pa: The Pennsylvania State University.

Introduction to Forest Management and Silviculture PowerPoint from Forest Resource Institute for Teachers, June 2009

Roth, Paul and Rance Harmon (2009). PA Tree ID PowerPoint  fpr Forest Resource Institute for Teachers. The Pennsylvania State University, Department of Ecosystem Science and Management & Cooperative Extension.

Smith, Sanford, and Paul Brohn (2002). Summer Key for Pennsylvania Trees. University Park, Pa: The Pennsylvania State University.

Author

Christine King - Purchase Line South Elementary - Grade 6