Handbook of Nature-Study · Lesson CLXXXVIII · Topic 28: Tree study
188. Tree study: adopting a tree for a year
Goal: Your child adopts one tree, describes it carefully, and measures its girth, its thickness and its height by its shadow.
You'll need
- A tape measure (a cloth sewing tape is fine)
- A yardstick or a stick exactly 3 1/2 feet long
- A nature notebook and a pencil (colored pencils if you have them)
- Crayons or watercolors
- A calculator if you like
What's in the book
This lesson is a set of questions for following one tree through the year: Autumn Work, Winter Study and Spring Work, ending with how to measure a tree's height by its shadow and its thickness from its girth.
The lesson, step by step
Choose your tree
Begin in autumn. Walk around and let your child pick one tree to visit all year: in the yard, on the street or in a park. Give it a name in the notebook, and its kind if you know it.
Autumn questions
What is the color of the tree in its autumn foliage? Sketch it in water colors or crayons, showing the shape of the head, the relative proportions of head and trunk.
What is the color of the bark? Is the bark smooth or rough? Are the ridges fine or coarse? Are the furrows between the ridges deep or shallow? Of what use is the bark to the tree?
As the leaves begin to fall, can you find two which are exactly the same in size and shape?
How thick is it?
Measure around the trunk three feet from the ground. The book says:
To find the thickness of the trunk, divide the circumference just found by 3.15.
Today we use 3.14 (the number pi), but the answer comes out almost the same. Work it out together.
How tall is it?
On a sunny morning, push the 3 1/2-foot stick into the ground so 3 feet stand up. Right away, measure the stick's shadow and the tree's shadow. The book's example:
Supposing that the shadow from the stick is 4 feet long and the shadow from your tree is 80 feet long, then your example will be: 4 ft.:3 ft.:: 80 ft.:? Which will make the tree 60 feet high.
In plain words: the tree is as many times taller than the stick as its shadow is longer than the stick's shadow.
Plans for winter
Read a few winter questions to look forward to:
If we place a nail in a tree three feet from the ground this winter, will it be any higher from the ground ten years from now?
(Just think about it; don't hammer a nail into your tree.) In February you will bring in a twig, put it in water, and watch the buds open.
Plans for spring
At what date do the young leaves appear upon your tree? What color are they?
What birds do you find visiting it? What insects? What animals seek its shade?
Nature notebook
Start a "My Tree" page: a sketch of the whole tree, a leaf or a leaf rubbing, a bark rubbing (paper on the bark, rub with the side of a crayon), the date, the girth, the thickness and the height.
Afterwards
Visit the tree once a month. Each season, add a new sketch and answer that season's questions from the book page.
Tip
Making a leaf print or rubbing of the two leaves that differ most is a quick way to see how much leaves on one tree can vary.
Answers to the book's problems
Book example: 4 : 3 = 80 : 60, so the tree is 60 feet tall. Thickness = girth divided by 3.14; for example, a 63-inch girth means a trunk about 20 inches through. A nail will not move higher: trees grow taller only at the tips of their twigs, and grow thicker by adding a ring of wood each year.
Worked out for this site from the scan. If a number in your copy differs, trust the book.