314 



NEW ENGLAND TREES IN WINTER. 



from a distance equal to several times the length of the tree, the 

 height of a 10 ft. pole beside the trunk or a mark on the trunk 

 of known height may be compared with the height of the whole 

 tree. Instruments for more accurate measurement are on the 

 market under the name of hypsometers. A home-made instru- 

 ment may readily be constructed which has been found to compare 

 favorably in accuracy with the expensive Faustmann hypsometer 

 of which it is a modification. A rectangular board about a foot 

 in length is ruled in squares or more conveniently has squared 

 coordinate paper pasted on one side (fig. 1). Care should be 



M 



K 



Fig. 1. Home-made Height Measurer. 



observed that the top of the board AF is straight and accurately 

 parallel to the lines running lengthwise of the paper. The line 

 MC is numbered from M in any convenient unit, say up to 100, 

 and using the same unit, the line HK is numbered in both direc- 



