A number of different instruments can be used to determine height. With the exception of the Biltmore stick, all work on the same principle of taking two slope readings. The scales in each instrument are just housed in a different setting.
- Clinometer – as shown in Chapter 1
- Relaskop—see section 3.3
- Laser range finder/electronic hypsometer (these do the math for you!)
- Biltmore stick hypsometer
Though not commonly used, a Biltmore stick is an inexpensive tool for obtaining a rough estimate of tree height. It is based on the principle of similar triangles (Figure 2.14).