Have you ever wanted to know how to measure the height of a tree? Here are three ways to measure a tree height.
Using a Biltmore Stick
There's actually a ruler made for this specific purpose. It's the Biltmore Stick. Here's a great article giving detailed instructions on using the Biltmore Stick.
Using a Yard Stick
This information comes from the Indiana Department of Natural Resources
"A simple and quite accurate method of measuring tree height can be done with a yardstick. To do this, temporarily mark a spot 4 feet up from the base of the tree to serve as a sighting point for measuring tree height. A ribbon around the tree or masking tape may work well or have a friend hold his/her hand at a point 4 feet up on the tree’s trunk. Next, back away from the tree with the yardstick held straight up and down as if you were sighting straight up and down the tree. It is very important that your stick be held straight for an accurate measurement. Keep backing up (about 100 feet) until the 4 foot section you marked on the tree occupies exactly ONE INCH on your yardstick. Now, without moving your stick, site to the base of the tree and then to the top of the tree noting the number of inches the tree height occupies. Remembering that one inch on your yardstick equals four actual feet, multiply the measured tree height time four to determine the total tree height."
and, of course, there's a phone app to handle it
You can try the AboReal app.
Disclaimer here: I haven't used this app, but it looks pretty good. As always, research it thoroughly before you download anything.