Sometimes, whether wishing to cut down a tree or take measurements for forestry work, it is necessary to measure the height of a tree. There are several methods of calculating tree height, but they almost always involve complex calculations, expensive equipment, or totally unreliable “guesstimates.” Luckily, there is a super easy way to calculate the height of a tree that involves using nothing but a stick (and maybe a 100′ tape).
For this exercise, you will only need two things.
- 100′ Tape (optional)
1. Find an Arms-Length Stick
To start, you will need to find a stick. Any stick will do. Make sure it is long enough to reach your eye when your arm is fully extended in front of you, however.
2. Hold the Stick Straight Up With the Bottom Level with Your Eye
Next, grab on to the base of the stick and hold your arm out fully extended in front of you, being sure to keep your hand at eye level. Ensure the stick is just long enough to reach your eye from this position. Adjust your grip as necessary to get just the right length. Once you are sure the stick is at the right length, hold the stick straight up at 90 degrees, being sure once more that your hand is still held up at eye level.
3. Stand in a Position Where the Top of the Stick Is Visually Aligned With the Top of the Tree
From here, get a visual of the tree you wish to measure and adjust your physical distance from the tree until, from your visual perspective, the top of the stick you hold is perfectly aligned with the top of the tree. Try to stay on the same ground level as the tree while moving around. The final position should resemble something like the diagram below.
4. Measure Your Distance From the Base of the Tree
From here, your physical distance is roughly equal to the height of the tree! All that is left to do is to measure that distance, which you can do either by physically measuring the distance with a 100′ tape or estimating the distance using pacing.
Measuring With a 100′ Tape
Measuring your distance from the tree with a 100′ tape is the most accurate way to do so, but it is also fairly inconvenient. First, you will need to get yourself a tape if you don’t have one. Then, take one end of the tape and secure it to the tree and walk back to your previous position (hopefully you marked it). All that is left to do then is to record the measurement.
Estimating by Pacing
The less accurate but more convenient method of estimating distance is by using pacing. Measuring distance with pacing is simple. All you need to know is the average distance of your pace (one pace is defined as two steps. Every time your right foot touches the ground is one pace, for example). Count how many paces it takes you to walk to the tree from your position and multiply that number by your average pace length.
If you don’t know your pace length, you can use the table below to estimate it based on your height:
|Height||Women’s Pace (Feet)||Men’s Pace (Feet)|
|5 ft. 0 in.||4.2||4.2|
|5 ft. 1 in.||4.2||4.2|
|5 ft. 2. in.||4.3||4.3|
|5 ft. 3 in.||4.3||4.3|
|5 ft. 4 in.||4.3||4.5|
|5 ft. 5 in.||4.5||4.5|
|5 ft. 6 in.||4.5||4.5|
|5 ft. 7 in.||4.7||4.7|
|5 ft. 8 in.||4.7||4.7|
|5 ft. 9 in.||4.7||4.8|
|5 ft. 10 in.||4.8||4.8|
|5 ft. 11 in.||4.8||4.8|
|6 ft. 0 in.||5||5|
|6 ft. 1 in.||5||5|
|6 ft. 2 in.||5.2||5.2|
|6 ft. 3 in.||5.2||5.2|
|6 ft. 4. in.||5.2||5.3|
|6 ft. 5 in.||5.3||5.3|
Remember: A single pace is equal to two steps!
5. Make Final Adjustments to Your Calculation to Get the Final Tree Height
Great, you are almost done finding the height of the tree! All that is left to do is make a few adjustments based on the circumstances. First, because you were holding the stick at eye level, it is likely the base of the stick was aligned with eye level on the tree as well. To adjust for that, add on your eye height (generally your total height minus six inches) to the distance measurement in step 4. Congratulations! That’s your final answer!
There may also be times when you are unable to stay on the same level as the tree, maybe going a bit downslope or upslope from its base. If that’s the case, simply make a heuristic adjustment. If you went downslope, subtract the approximate elevation decline. If you went upslope, add the approximate elevation gain.
Why it Works
While it may seem odd, this method works by essentially doing pre-calculated trigonometry. If you recall from your high school geometry class, the internal angles of a triangle must equal 180 degrees. When we measure trees, we know the tree stands at roughly 90 degrees from the ground, which gives us 90 more degrees to work with. If we ensure the bottom angle is 45 degrees, we can guarantee the top angle is 45 degrees also, and if that is true then the adjacent side (bottom) and opposite side (right) of the triangle must be identical. X=X.
When we hold a stick to our eye and flip it up, we are creating a small triangle with two equal sides to be able to sight-in 45 degree angles on a much larger triangle, ensuring once more that the opposite and adjacent sides are equal. When we pace our distance to the tree, we are measuring X, which measures simultaneously two sides of the triangle, including the height of a tree!
…Hello? Did I lose you? Ok, good!
Why This Is the Best and Easiest Way to Measure Tree Height
There are many ways to measure the height of a tree, and to be honest, I have tried them all. Unless you are measuring the (former) height of a tree you already cut down, the only way to do it is by using some form of trigonometry. In some cases, you use a clinometer to measure an angle and do the math manually (annoying and time consuming, as well prone to error). In other cases, you can buy an expensive device ($2,000) to measure angles and distances and do some automatic trigonometry for you. On the other hand, you can use an ancient technique known as “eyeballing it.” While eyeballing it is popular, it has certain accuracy issues.
While all these methods can work, they all have a significant drawback. Using a stick, you can get incredibly accurate results using cheap-as-free equipment and do almost no math to get the answer. It is by far the best and easiest method of calculating tree height. Once you get the hang of it, combine it with other mensuration skills like measuring DBH and then get usable data like volume estimates of how many cords of firewood are in a tree. Have fun!