While it's possible to measure the height of a tree from the ground, dropping a line from the very top gives a much more precise measurement than using a clinometers
or even a laser.
So they decided to go out and measure, using a clinometer
made out of cardboard, a plastic straw, and a plum line.
Foresters, arborists, and serious Big Tree hunters dedicated to accurate heights use clinometers or transits to measure angles; a tape measure or infrared laser rangefinder to measure distances; and scientific calculators and simple trigonometric formulas to crunch the numbers.
A clinometer will ensure that you are directly below the edge of the crown.
(about $90): For measuring height, slope, and vertical angles.
An Army Corps of Foresters armed with hypsometers, transits, clinometers
, and trigonometric calculators?
Foresters usually use Abney levels, clinometers
, hypsometers, or transits to determine the height.
Vertical angles--up and down--can be measured with a clinometer that references gravity.
If you are unwilling to spring for the cost of a handheld clinometer, there is another option if you own an iPhone: Several inexpensive apps turn your phone into an accurate clinometer.
Measure it in flight with your clinometer and you'll always have a rough sense of what's realistically within gliding distance.
Then walk up the side of the runway to where you expect to lift off and take clinometer sightings of the surrounding terrain.
A clinometer can be used to judge if a cloud can be topped.