Based on the relatively simple trigonometric principle of similar triangles, a Biltmore cruiser stick is a yardstick-styled "instrument" used to measure tree diameters and tree heights without climbing the tree or wrapping a tape around the trunk. Using this one stick, a tree's dimensions can be easily determined very quickly for approximate values and checking eyeball estimates.
Foresters often use the cruiser stick tool to keep their ocular estimates honed but most timber estimation data is measured and compiled using more sophisticated and accurate tools like diameter tapes and clinometers to measure diameter and heights. Some of these instruments - a perfect example is a relascope - can actually do all the calculating from one spot. They are also pricy.Just a little history on our simple Biltmore stick. The Biltmore cruiser stick was developed for forestry students in the late 1800's at Professor Carl Schenck's forestry school on Biltmore Estate near Ashville, North Carolina. The instrument has passed the time test and is included in every forester's tool kit.
So, lets make and calibrate a Cruiser Stick. Materials you need to get started:
- 1 straight strip of wood approximately 30 inches long, one or two inches wide and one quarter inch thick
- 1 engineers scale (an inch rule broken into tenths)
- 1 small carpenter's square
- 1 yardstick with straight edge (preferably metal)
- 1 lead pencil and a permanent black pigment ink pen
- 1 hand calculator with a square root function key
- Optional: a 25" reach Biltmore stick to check your calculations