- Leaf samples
- Measuring tape
- Tree pictures from old calendars or magazines
- Pencil and Paper
- Optional: Tree Identification Books
(The Arbor Day Foundation has a tree identification booklet available called "What Tree is That?"
Holding a community tree contest is a great way to get kids interested in the trees in their neighborhoods. Students will learn some of the techniques used to measure champion trees and have the opportunity to identify some community trees.
Tell the students they are going to take part in a "Tree-mendous Trees" contest to find the biggest trees in town or in the neighborhood community. Ask students to think about the trees they see on their way to school. Where do they see the biggest trees...in yards, in parks, around the school? Record their comments. Then ask them how many different kinds of trees they see.
Help students understand that not all tree species grow to be the same height. Some trees, like the Redwoods in California, are giants towering more than 250 feet above the forest floor while a Flowering Dogwood may only reach a height of 35 feet. Both could be considered champions if they were the largest of their kind.
Explain to students that trees are divided into two main groups:
conifer and broadleaf.
are trees with cones that have needle-like or scale-like
(awl-shaped) leaves. Most conifers are evergreen since
they do not lose all their leaves at once. Pines, firs,
cedars and spruces are conifers. Larches and bald cypresses
are conifers, they have cones, but they lose their leaves
trees are trees with leaves that are shed annually.
They may bear flowers, fruits or nuts. Oaks, maples,
birches, and sycamores are just a few of the many different
kinds of broadleaf trees. Broadleaf trees are sometimes
referred to as deciduous trees. In warm climates, some
broadleaf trees, like magnolias, do not shed all their
leaves at the same time so they appear to remain evergreen.
Palms are not trees. We often call them trees because
of their size and similar role they play in tropical climates,
but they are actually woody monocotyledons that bear fruit
Ask students to think again about trees that they pass en
route to school.
For visual learners, it is helpful to have a leaf sample
from a conifer with needle-like leaves, a conifer with
scale-like leaves, and broadleaf tree. An inexpensive
acrylic picture frame works well to keep brittle leaf
samples protected and in place while still offering students
a clear view of actual leaves.
Cut tree pictures from old calendars or magazines and
have the students group them as conifer or broadleaf.
Take a walk around the school grounds and have the students
distinguish between conifer and broadleaf trees, then
have the students calculate the ratio of conifers to broadleaf
trees in the area visited.
- Are there more conifers or broadleaf trees?
- Can any generalizations be made about where broadleaf
and conifers are planted? (Often conifers are planted
in parks or large, green spaces because of their pyramidal
- Where might you go to look for the biggest broadleaf
trees? Where might you find the biggest conifers?
From the comments generated by the students, determine
some of the best areas in the community in which to find
large, mature trees.
Determine how large an area of the community is feasible
to include in the contest. Is transportation available
to your class or do you need to stay within walking distance
of the school? Are there many sites in the community with
large trees, or just a few? Designate an area and set
Your class may choose to simply search for the biggest
tree in the designated area. They may wish to find the
biggest broadleaf and the biggest conifer. Students might
learn to identify a particular tree species, perhaps their
state tree, and hunt for this kind in the community.
Our experience is that students profit from learning how
to actually identify a tree by leaves, bark, shape, fruit,
flowers, and buds. Learning how to use a good tree identification
key is a great introduction to biology and dichotomous
tree key use. (For upper elementary classrooms, The National
Arbor Day Foundation has the
Trees are Terrific unit that teaches taxonomy
and tree identification.)
In all cases, students should be able to make the distinction
between conifer and broadleaf trees and understand how
to properly measure a tree.
Foresters have a special formula to measure trees. This
formula includes the tree's height, circumference, and
crown spread. A tree receives one point for every foot
of height, one point for every inch of circumference (taken
at 4 1/2 feet), and one-fourth of a point for every foot
of average crown spread.
Explain to the students that they are going to practice
measuring trees before looking for a "Tree-mendous Tree"
winner. Divide students into groups of three or four.
Each group will need measuring tape, yardstick, and a
pencil and paper to record their findings.
It may be helpful to assign roles to each student within
a group. Group jobs include:
Recorder - records measurements and tallies
Investigator - takes the measurements
Manager - assists the investigator to make sure
measurements are accurate and is responsible for the
measuring tape and yard stick
Reporter - reports findings to class
Take students to a nearby area with enough trees to
allow each team to measure a tree. Explain that they are
measuring these trees for practice and later they will
search for the Tree-mendous Trees in their community.
The height of a tree is measured from the top of the tree
to the ground. Follow these steps to measure tree height:
1 - Students should stand on level ground
to take measurements.
2 - The student investigator extends his/her
arm out straight so that the top of his/her fist is
at eye level. Carefully using the yardstick, the manager
makes sure the top of the investigator's fist is at
eye level and then measures the distance from the investigator's
fist to the investigator's eye. The recorder writes
down this information.
3 - The investigator directly faces the tree
to be measured holding the yardstick vertically in his/her
extended fist so that the distance from the top of his/her
fist to the top of the yardstick is the same eye-to-fist
distance measured in the previous step. The manager
checks the measurement then makes sure the investigator's
arm is straight out, fist at eye level with the yardstick
straight up and down.
4 - The investigator slowly (and carefully)
walks backward away from the tree until he/she can see
the base of the tree by looking over the top of the
fist and the top of the tree by looking over the top
of the yardstick.
5 - The manager measures the distance, in
feet, from the investigator to the tree. This distance
is the height of the tree.
6 - The recorder writes down the height measurement
and gives the tree one point for every foot of height.
The circumference of a tree is the distance around its
trunk. The circumference is measured 4 1/2 feet from the
ground. If the tree forks or if there are branches at
the 4 1/2 foot mark, the circumference is measured at
the narrowest point below the 4 1/2 foot level.
Follow these steps to measure circumference:
1 - The investigator holds one end of the
tape against the tree trunk at a measured point 4 1/2
feet above the ground.
2 - The manager wraps the tape around the
trunk until it reaches the starting point.
3 - The investigator reads off the measurement
in inches. This is the circumference of the tree.
4 - The recorder writes down the circumference
and gives the tree one point for every inch of distance
around the trunk.
The crown spread of a tree is the distance its branches
spread away from its trunk. The crown spread is calculated
by measuring the distance of the widest spread and the
distance of the narrowest spread. These two figures are
then added together and divided by two to get an average.
A tree receives 1/4 of a point for every foot of the average
crown spread. Follow these steps to measure crown spread:
1 - The investigator finds the branch that
sticks out the farthest from the trunk and stands directly
under its tip.
2 - The reporter goes to the opposite side
of the tree and stands under the tip of the branch extending
farthest out on that side.
3 - The manager measures the distance in
feet between the investigator and the reporter and the
recorder records this number. This distance is the widest
point of the crown spread.
4 - Next the investigator finds the branch
nearest the trunk of the tree and stands directly under
5 - The reporter goes to the opposite side
of the tree and stands under the tip of the branch closest
to the trunk on that side.
6 - The manager measures the distance in
feet between the investigator and the reporter and the
recorder records this number. This distance is the narrowest
point of the crown spread.
7 - The recorder adds the two distances together
and divides by two to get an average crown spread. The
recorder then awards the tree 1/4 of a point for every
foot of average crown spread.*
* If students have not yet studied fractions the teacher
may wish to instruct the students to divide the average
crown spread by 4.
Up a Winner
Before starting the "Tree-mendous Trees" contest:
- Review conifer and broadleaf distinctions.
- Make sure students understand how to correctly measure
- Inform the community of the project so people will
not be surprised to see the kids in their yards.
- Ask for parental volunteers to accompany the students.
- Determine how the students will get to the designated
area or areas to measure trees. Make necessary transportation
- Create a form for the student recorders to use in
their record keeping. The form should include:
- The formula for measuring tree size
- Room for students to describe the location of
the tree. If you are measuring trees in neighborhood
yards, students can record the house address where
the tree is located. If you are measuring trees
in parks, students will need to write down a brief
description of each tree's location along with some
distinguishing characteristics of each tree. In
all cases, students should differentiate whether
the tree is a conifer or broadleaf.
When you are ready to begin, give each group a recording
form. Make sure they have something firm to write on and
pencils to record their results. Check with each group
manager to see that they have a tape measure and yard
Establish an organized system for groups to explore the
designated area or community. When students return to
the classroom, have each group reporter report their findings
to the class and compile results.
Have students put together a list of the community's biggest
trees. Interested students may wish to do research to
learn more about winning tree species and share their
results with the class.
After determining the "Tree-mendous Trees" contest winner(s),
your class may wish to present an award certificate to
the owner of the tree if it is on private property. Or,
make a presentation to the mayor or city council if the
tree is on public property. Announce the tree winners
on Arbor Day. Include a visit to the winning tree(s) as
part of your school's Arbor Day celebration.