Methods Used to Measure The Height of a Tree

The vertical distance between a tree’s base and its topmost branch’s tip is simply known as the tree’s height.

How to determine the height of a tree

Methods of determining tree height are of mainly two types: Direct and Indirect. The selection of the method depends on the location or fate of the tree:

  1. Trees that have been felled are measured immediately with linear tape or a graduated pole from base to tip when they are lying on the ground.
  2. Standing trees can have their height determined directly or indirectly. The majority of methods are indirect because it is frequently impossible to reach the tip or merchantable limit.
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1. Direct methods

a. Climbing using a graduated pole and tape: An accurate method, but only applicable to specific species and under limited circumstances. This expensive, risky method is typically only used in experimental ventures.

b. Height sticks or rods: are a trustworthy technique with an instrument error of under 1%. However, for trees taller than 20 meters, this method can also be pricey.


2. Indirect Methods

a. Non-instrumental methods:

  • Shadow method:

It includes fixing a pole of a practical length upright in the ground and measuring the height of the pole above the ground. Additionally, the poles and the tree’s shadows are measured.

  •  Single pole method:

A 1.5 m pole is held vertically at arm’s length in one hand with a piece of it above the hand that is the same length as the pole’s distance from the eye.

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b. Instrumental Method:

  • By using instruments like hypsometer, clinometer, altimeters, Abney level etc.
  • All these instruments are based either on the geometric principle of similar triangles or on trigonometric principles.
  1. Measurement of the height of trees in the plane area:
  2. Measurement of the height of trees in a sloped area:

Measurement of the height of trees in the plane area:

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The height of the tree is calculated with the help of the tangents of the angle to the top and the distance of an observer from the tree.

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Measurement of height of trees in a sloped area:

  • Where the observer is standing at such a place that the top of the tree is above eye level and the base below it.
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  • Where the top and base of the tree are above eye level.
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  • Where the base and top of the tree are below the eye level
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Because all hypsometers presume that trees are vertical, trees that are slanting either away from or toward an observer will be overstated. If measurements are done so that the lean is to the left or right of the observer, this error will be reduced.

Hence, the height of the tree located at various places having various shapes can be calculated through these above-mentioned methods.

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