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Leaf Identification

Keywords: Conifer, Deciduous, Photosynthesis, Oxygen, Carbon Dioxide, Chlorophyll, Alternate, Opposite, Margin, Serrate, Pinnate, Palmate, Vein, Leaflet; Grade Level: Grade 3; Total Time Required: Three forty minute classes; Setting: Classroom, Outdoors with a variety of trees(I use a State Park)

Subjects Covered: Science, Arts

Topics Covered: Leaf types, Tree types of Pennsylvania, Using a key, Importance of leaves

Goals

  • The students will understand the difference between a conifer and deciduous tree.
  • The students will understand how leaves make food.
  • The students will use a leaf key to identify various Pennsylvania tree leaves.

Materials Needed

 

A variety of Pennsylvania tree leaves, and a leaf key for each student.

State Standards Addressed: 3.2.4, 3.2.7, 3.2.10, 3.3.4, 4.3.4, 4.6.4

Methods

 

Lecture, Using a guide, Applying skills

Introduction

Discuss of the different ways that trees can be identified. (Bark, location, leaves, etc.) Explain how leaves supply animals with oxygen while using carbon dioxide, chlorophyll and sunlight to make food for the tree. I often draw a diagram of the photosynthesis process.

Next, I hand out a variety of leaf samples on small branches that I bring in from home. (I am fortunate to have a wide variety of trees on our property) I make sure that I have samples of both deciduous and coniferous trees. We discuss and look at the differences between them as well as name some examples found in our state. I mention that our Pennsylvania state tree is the Eastern Hemlock and shown the a sample. We use the Summer Key for Pennsylvania Trees to identify several leaf samples. I allow them to help one another and offer help as needed. I point out some of the characteristics used such as opposite and alternate leaf arrangements on a limb. I make sure that the students understand the difference between a leaf and a leaflet. Other key terms illustrated and explained are serrate, pinnate, palmate, vein, and margin. These are all found and illustrated in the key. It may be helpful to get transparencies of these as well. They can be obtained from the Publication Distribution Center at The Pennsylvania State University, 112 Agricultural Administration Building, University Park, PA 16802.

I ask the students to bring in a small tree branch the following day to be identified. We review vocabulary words and pass the branches around to identify. Sometimes we take a short hike outside where I have previously place small branches at the base of the tree it came from. I ask the students to use their keys to identify it and record the proper name on a piece of paper. ( I try to have between six and ten different trees) This is sometimes hard to do at a school location, however very easy at a state park. Once we return to the classroom answers are discussed. When mistakes are made we use the key for that particular leaf as a group. This could be used as a quiz grade along with the vocabulary covered.

Other activities to accompany this topic are leaf rubbings, aging trees, planting trees which can be obtained through DCNR, having a guest forester, and a unbelievable amount of wonderful books and videos through United Streaming.

Evaluation

 

Participation, quiz on vocabulary and skills taught

Literature Cited

 

Summer Key for Pennsylvania Trees copyright The Pennsylvania State University 2002

Pa DCNR Web site: www.dcnr.state.pa.us

Trees of Pennsylvania Web site: www.treesofpa.com

Author

Ben Porkolab, Woodland Elementary