 Here are some helpful hints for measuring tree height. First, remember to always take height measurements from a distance greater than you think the tree is tall. When using the percent side of the clinometer, it can be read directly when standing 100 feet away from the tree. But when reading from the topo side of the clinometer, you should be 66 feet away from the tree to read measurements directly. Next, always measure tree height when you are standing perpendicular to the tree lean. Finally, it can be helpful to place a walking stick or something with a known height against the tree you want to measure. It makes it easier to identify the tree you're measuring. And if it's difficult to see the base of a tree due to forest undergrowth, you have something to side on for your base measurement.