178 



FARM FORESTRY 



several forms and are known by different names. A simple 

 one is the clinometer, which when sighted at the tip of a tree 

 from a distance of 100 feet will read directly the height of 

 the tree. 



There are several methods for finding the heights of trees 

 without instruments. One of the simplest methods is to meas- 

 ure the length of the shadow cast by the tree and the length 

 of the shadow cast by a lo-foot pole set perpendicularly in 

 the ground. When the length of the shadow cast by the tree 



is multiplied by the length of the pole and the product divided 

 by the length of the shadow cast by the pole the result will 

 be the height of the tree. The heights of trees can be found 

 in this way only when they stand in the open. 



A staff about 4 feet long, one end held to the eye and 

 grasped at arm's length and then held vertically in front of 

 the eye, can be used in measuring the height of trees. A posi- 

 tion is found out from the base of the tree where the top of 

 the tree will be seen just over the top of the pole and the base 

 of the tree over the hand. The distance the observer is then 

 away from the tree will be the height of the tree. 



