Measure the height of a tree
Measure the height of a tree using a tape measure, homemade clinometer or smartphone app, applying basic geometry to record your findings.
Step-by-step guide to measure the height of a tree
Using basic math to calculate the height of a tree & where it'll fall #tree #treeremoval #tools #diy
Step 1
Gather all the Materials Needed and bring them outside to the tree you want to measure.
Step 2
Decide which measuring method you will use: make a homemade clinometer or use a smartphone clinometer app.
Step 3
If you chose the homemade clinometer tape the straw along the straight edge of the protractor so you can look through it.
Step 4
If you chose the homemade clinometer tie the string to the center hole of the protractor and attach the small weight so the string can hang freely.
Step 5
If you chose the smartphone app open the clinometer app and make sure it shows angle degrees when you point the phone.
Step 6
Measure the height from the ground up to your eyes with the tape measure and write down that eye height on your paper.
Step 7
Walk straight away from the tree until you can see the top of the tree clearly and stop at that spot.
Step 8
Use the tape measure to measure the horizontal distance from the tree trunk base to where you are standing and write that distance down.
Step 9
If you built a clinometer hold it at your eye level look through the straw at the top of the tree and read the angle where the string crosses the protractor then write the angle down.
Step 10
If you are using the smartphone app point the phone at the top of the tree and read the angle in degrees on the app then write that angle down.
Step 11
Calculate the tree height using the formula height = distance × tan(angle in degrees) + eye height using a calculator and write the result.
Step 12
Draw a simple labeled diagram of the triangle you used showing the distance angle eye height and final tree height and add your measured numbers.
Step 13
Share your finished measurement process and diagram on DIY.org.
Final steps
You're almost there! Complete all the steps, bring your creation to life, post it, and conquer the challenge!
Help!?
What can we use if we don't have a protractor, straw, string, small weight, or tape measure listed in the materials?
Substitute a printed protractor or straight ruler taped to a stiff card for the protractor, a rolled-up paper tube for the straw, a paperclip or washer tied as the small weight to the string, and use a cloth tape, long ruler, or count measured paces for the tape measure while following Steps 3–6.
What should we do if we can't clearly see the top of the tree or the clinometer reading seems unstable?
If the top isn't visible or the angle wiggles, move farther back as in Step 6 until the top is clear, make sure in Step 3–4 the straw is aligned and in Step 4 the string hangs freely untwisted while holding the clinometer vertical or steady the smartphone with both hands before recording the angle in Step 8 or 9.
How can we adapt the activity for younger children and for older kids who want more challenge?
For younger children, have an adult perform Steps 5–10 (measure eye height, distance, read angle, compute height) while the child draws the labeled triangle in Step 11, and for older kids repeat measurements at different distances, compute averages, and check the height using the height = distance × tan(angle) + eye height formula in Step 10 for error analysis.
How can we extend or personalize the tree-measuring activity after finishing the basic measurement and diagram?
Extend the project by measuring several trees from different distances using Steps 6–10 to compare heights, decorating and improving your homemade clinometer, taking photos of each Step 3–11 to create a photo tutorial, and uploading your labeled diagrams and process to DIY.org as instructed in Step 12.
Watch videos on how to measure the height of a tree
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Facts about measurement and geometry for kids
📏 Many pocket tape measures are about 5 m (16 ft) long — plenty to measure the ground distance from you to a tree.
📱 Smartphone clinometer apps use your phone’s accelerometer and gyroscope to measure angles quickly and easily.
🪵 The old-fashioned "stick method" uses a stick held at arm’s length to make similar triangles — no calculator required.
🌲 The tallest known living tree, Hyperion (a coast redwood), is about 115.92 m (380 ft) tall — taller than a 35-story building!
📐 With similar triangles or basic trig, tree height ≈ distance to tree × tan(angle to the top).
How do you measure the height of a tree with a clinometer or app?
What materials do I need to measure a tree's height?
What ages is measuring tree height suitable for?
What are the benefits and safety tips for measuring tree height (plus variations)?
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