The main objective of measurement of height of a tree is to find out the volume.
Here are the different methods by which we can get the height of the tree:
- Ocular method: ocular estimate is not reliable and serious errors may result if the estimator has no previous experience of work.
- Non-instruemental method: includes;
(a).shadow method: in this method a pole of convenient height is fixed upright in the ground and it's height above the ground is measured.the shadow of the pole and trees are also measured.the height of the tree can be calculated by simple proportion as :
Where AB is tree height
ab is portion of pole above ground
BD is lenght of shadow of tree
bd is shadow of ab.
(b) single pole metjod: the observer holds a pole of about 1.5m lenght vertically at an arm's length in one hand , in such a way that the portion of the pole above the hand is equal in length to the distance of the pole from the eye.
Let AB be any tree , ac a pole held at b vertically,so that distance from observers eye E to be is equal to ab.
- Instrumental methods:the instruments used are ;
a)Hypsometer: determines height of standing trees
b)Altimeter: typically an altitude measuring instrument ,one such instrument has been decided to determine heights of trees.
c)Clinometer:measures angle of slope.Can be used for determining the heights of trees by trigonometric methods.