Tree Identification by the Use of Leaves

Elaine E. Messal               Henry Clay Elementary
                               13231 South Burley
                               Chicago IL 60633
                               312-535-5600

Objectives:

1) Utilize the phenomenological approach to motivate students at the sixth grade 
level to understand how leaf arrangement and structure can be used for tree 
identification.
2) Develop the ability and desire to use concepts presented to identify all the 
trees included in the mini-teach plus the remaining ones in the neighborhood.

Materials needed:

1) Five motivating clue statements on posters 
2) Two large sheets of construction paper for every two students
3) Four sheets of typing paper for each student 
4) Six leaf samples from the local area for every two students 
5) Prepared leaf drawings for performance assessment
6) Herbarium collection and leaf keys for display   

Strategy:    

1) The night or morning before the lesson, collect six different leaves from the
local area for each pair of students.  Press them between two folded sheets of 
construction paper and seal them with masking tape. 
2) Divide the class into groups of two and give each pair a sealed set of leaves 
plus eight sheets of typing paper. 
3) Display the five motivating clue statements which follow and have the 
students guess what is in each set. 
   clue 1 One of us is believed to be the oldest and largest of all living 
          things. 
   clue 2 Some extinct species of us have been petrified.
   clue 3 Some of us have received names of famous people such as Abraham 
          Lincoln and General Sherman.
   clue 4 Always use our multicultural scientific names, which are the same 
          throughout the world, if you don't want to make a mistake naming us.    
   clue 5 The part of us that manufactures food is squeezed between the papers
          on your desk.  Name that part.  
          Note: Clues 1, 2, and 3 refer to the coniferous giant sequoia tree, 
          and the final answer for all five clues is LEAVES OF TREES.
4) Each pair of students who are sure of the answer should raise their hands and 
secretly give the answer to the teacher.  Jelly candy leaves may be given as a 
reward.
5) When everyone knows that the enclosed objects are leaves the sets are opened 
and each leaf is sketched by each student.
   step 1 A sheet of typing paper is placed over each leaf one at a time.
   step 2 Students use their pencils and sketch over each leaf with an acute 
          angle between the pencil and the paper so the side of the graphite is 
          used.  They must press hard to show entire leaf blades, margins, and 
          petioles.
6) After the leaves are sketched, ask the students to observe and identify the 
following: 
   Deciduous Trees 
        Margins (entire, serrate, lobed, toothed)
        Venation (parallel, palmate, net)
        Shapes (oval, linear, heart, fan, different shapes from the same tree)
        Types (simple, compound, double compound)
        Arrangement (alternate, opposite, whorled)
   Evergreen Trees 
        Needlelike (Bundles of 2-5, clustered)
        Scalelike
7) Show a leaf identification key to develop the concept of identification by 
the use of the above structures.  Name the six leaves sketched.
8) Show other examples of leaves in the local area by using an herbarium 
collection or fresh samples.
9) Take the class on a walk around the school building or local area and 
identify trees by using the leaf structures and arrangements observed and 
discussed in class. 
10) Introduce the importance of using scientific names.  They are the same      
throughout the world.  The same common names have been given to more than one  
plant and improper identification has occurred.  Asimina triloba is deciduous 
and Carica papaya is evergreen, and both have been called paw-paw or pawpaw.  
The common name sycamore has also been given to completely different trees. 
11) Assign students to write reports about trees which are native to an area  
or country representing their cultural heritage.

Performance Assessment:

1) Ask students to identify the trees studied on their walk when the same 
trees are observed again on the return trip.
2) Leaves sketched in class and observed during the walk should be labeled 
correctly in a station to station test conducted in the classroom.  Place
numbers on each sketch, fresh sample, or herbarium sheet, and tell the 
students to write the correct name for each leaf as they are held up or 
observed at a specific location.
3) Require students to define or draw two examples of different margins,
venation, shapes, types, and arrangements.

References: 
      
Petrides, George A., A Field Guide to Trees and Shrubs.

Zim, Herbert S., and Martin, Alexander, Trees A Guide to Familiar American 
Trees.

Elias, Thomas S., The Complete Trees of North America Field Guide and Natural 
History.

http://www.tree-identification.com/