measuring trees

i found this fascinating…yes, i need a life.

from the Old Farmer’s Almanac site, three ways to measure the height of a tree without risking your neck:

(1) A local New Hampshire forester uses a Biltmore stick, which is marked with a special scale. He paces off 66 feet from the tree, holds up the stick vertically, and sights along the marks to the tree’s top and bottom. The scale tells him the height of the tree. (2) If you don’t have a Biltmore stick, take a yardstick and walk 27 paces from the base of the tree. Give the yardstick to a partner and ask him or her to hold it at the spot where you stopped. Then walk 3 more paces and lie down on the ground (on your stomach) facing the tree. Have your partner mark the points on the yardstick where you see the top and the bottom of the tree. The tree will be about ten times taller than the measurement on the yardstick. (3) Stand far enough way from the tree that the angle of inclination when you look to the top is 45 degrees. You will have created a right triangle with two sides of equal length. Then pace off the distance to the tree, which should equal its height.

3 thoughts on “measuring trees

  1. dan_ad_nauseam says:

    1 and 3 are variations on the concept of proportion. Another approach is to take an object of known length, measure its shadow and the shadow of the tree, and work out the ratios.
    Of course, you could also take an object to the top of the tree, drop it, time the fall with a stopwatch, and calculate the height by the formula d = 1/2 * 9.8 * t^2.
    And there are more direct methods. Take a barometer, and find the landowner. Offer the barometer in exchange for the height of the tree.

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