You may need to know what it could hit if it falls, how high up the fruit is, or may simply want to establish bragging rights. Whatever the reason, measuring the height of a tree is not difficult. Below are four methods that work in most situations. All methods require that you are fairly level with base of the tree. This method requires a square piece of paper or card and a way to measure distance from the tree.
But keep in mind that height measurements should be looked at very critically. Walk away from the tree until the top of the tree corresponds with the tip of the stick, from your point of view. Then turn the stick horizontally and remember with which spot as far away from you as the tree is the tip of stick corresponds.
The height of the tree equals the distance from the tree to that spot. These methods assume the tree is not growing on a slope and the top of the tree can be determined by surrounding trees or by the round shape of the crown the actual top of the tree can remain hidden for the observer. Also, 'distance to the tree' is not entirely correct: it should be 'distance to the orthogonal projection of the tree's top on the ground'.
The difference between the 'distance to the tree' and that projection is half the diameter of the tree near the ground. Fold one corner over so it forms a triangle with the opposite side, then cut off the extra paper above the triangle. You should be left with the triangle you need.
The triangle will have one right 90 degree angle and two 45 degree angles. One of the short sides should be horizontal flat , and the other should be vertical pointing straight up.
You should be able to look up along the longest side by raising your eyes. The longest side, the one you'll be looking along, is called the hypotenuse of the triangle. Move back from the tree until you can sight the top of the tree at the top tip of the triangle. Close one eye and use the other to look directly along the longest side of the triangle, until you see the exact top of the tree.
You want to find the point where your line of sight follows the longest side of the triangle to the very top of the tree. Mark this spot and measure the distance from it to the base of the tree. This distance is almost the full height of the tree. Add your own height to this, since you were looking at the tree from the height of your eyes off the ground.
Now you have the full answer! To learn how this works, see the "Using a Clinometer or Transit" section. Method 2. Use this method if you only have a tape measure or ruler. You don't need any other equipment to use this method, and you should get an accurate estimate of how tall the tree is.
You will need to do multiplication and division problems, but no other math. Measure your height. Use a tape measure or yardstick meter ruler to measure your height while standing straight. Do this while wearing the shoes you will be wearing to perform this method. Since you'll need a piece of paper anyway, write your height down so you don't forget the exact number.
You'll need a single number, such as your height in inches, not a combination of feet and inches. If you're not sure how to convert into one number, you can use the height of a yardstick or meter ruler standing vertical instead 3 feet or 1 meter. Use the ruler's height and the length of the ruler's shadow anytime you are asked to use If you are in a wheelchair or cannot stand straight for another reason, measure your height in whatever position you'll be in when you go outside to measure the tree.
Stand on sunny, flat ground near the tree. Try to find a spot where your shadow falls along flat ground so you can get an accurate measurement. For best results, do this method on a bright, sunny day. If the sky is overcast, it may be difficult to precisely measure the shadows. Measure the length of your shadow. Use a tape measure or yardstick meter ruler to measure the distance from your heels to the tip of your shadow.
Or better yet, place the rock anywhere on the ground, and then position yourself so the tip of your shadow is at the rock; then measure from where you're standing to the rock. If the tree's shadow is on a slope, there might be a different time of day when the shadow avoids the slope either by being shorter or by pointing in the other direction.
Most trees grow straight upwards, so the highest tip of the tree should be above the exact middle of the tree. If you're having trouble seeing how wide the trunk is, draw a tight square around the base of the trunk and measure one side of that square.
Shadow lengths are proportional to the height of the object. In other words, your shadow's length divided by your height will always equal the tree's shadow's length divided by the tree's height. If you are 5 feet 1. Divide the answer by the length of your shadow. Using the example above, if your shadow is 8 feet 2.
If you're having trouble with the math, find a tree height calculator online such as this one. Method 3. Use this method as an alternative to the shadow method. While this method is less accurate, you can use it when the shadow method won't work, such as on an overcast day. Also, if you have a tape measure with you, you can avoid having to do math. Otherwise, you'll need to find a tape measure later and do some simple multiplication problems. Stand far enough from the tree so you can view the whole tree—top to bottom—without moving your head.
Your view of the tree should be as unobstructed as possible. Grasp the stick by the tips of the thumb and index finger and hold it out in front of you with your arm fully extended. The stick must be held vertical. Walk toward or away from the tree until the tip of the stick is visually lined up with the top of the tree and the bottom of the stick is lined up with the bottom of the tree. Your line of sight to the tree base should be as close as possible to horizontal.
In sighting to the top and bottom of the stick rotate your eye rather than your head. The distance from your eye to the base of the tree is equal to the height of the tree.
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