Biology/Chemistry

Data-gathering Activities Relating to Trees in Their Environment

 Charles Buzek John Spry School 2400 S. Marshall Chicago IL 60657 (773) 535-1400

Objective(s):

Upper grade elementary students will be able to determine heights of trees and their ages. A canopy map will indicate optimal growing areas for the tree.

Materials Needed:

measuring tape, pencils, quadrant (bolt, string, cardboard)

Strategy:

The quadrant consists of a cardboard rectangle large enough to copy 90 degrees from a standard protractor and provide room for a rolled-up siting tube. When the student can line up the top of the tree through the siting tube while maintaining a 45O angle, his distance from the tree is equal to the height of the tree. A less accurate but simpler method for determining tree height is to move back from a tree holding out a pencil until the tree is congruent with the pencil-making sure that the base of the pencil remains on the base of the tree-allow the top of the pencil to drop until the student can line it up with some object on the ground. A companion can then pace out the distance from the tree to the object sighted and thus determine the approximate tree height.

The age of the tree can be approximated by using the measuring tape to obtain the girth of the trunk at a point five feet above the base of the tree. This number is basically the age of the tree but bear in mind that this method does not work on saplings. Where possible the use of the tree-ring method on a cut tree could provide verification for the accuracy of this activity

Students should realize that the tree canopy does not radiate equally from the trunk of the tree. This can be demonstrated by making a map of the canopy. Students will select a tree, locate the eight cardinal points, and then proceed to pace out from the trunk in the eight directions until they are beneath the edge of the tree. This data will serve to allow the student to graph the entire canopy and show its relation to the trunk. Once the canopy has been diagrammed the student should enter into the data any external factors which may contribute to the characteristics he/she has plotted. These factors may be position of the sun or the location of other trees.

Performance Assessment:

Each team will collect data relative to their particular tree. By itself this information is relatively meaningless. But at the end of the individual information gathering stage the teams will submit their data to the instructor who will have designed a question for which analysis of the data will provide an answer. This answer will be provided by the team in the form of a short paragraph which develops their analysis of the data.

References:

Chinery, Michael The Complete Amateur Naturalist. Bloomsbury Books, London.

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