The Biltmore Pachymeter 



It might be stated, that any stick or pole, even a walking cane, 

 having parallel edges, will answer the purpose of establishing 

 and measuring upper diameters. The Biltmore Pachymeter is 

 merely a device convenient to handle. 



The observer holds the Pachy- 

 meter, pendulum fashion, by 

 the hand of the outstretched 

 arm in a position parallel to the 

 tree trunk, and he moves the 

 instrument backward or for- 

 ward until the edges of the slot 

 cut off even with the desired di- 

 ameter shown on the target. 

 Then, the eye following upv/ard 

 along the trunk and sighting 

 through the slot, that point on 

 the tree bole is readily obtained 

 where the bole cuts off with the 

 edges of the slot. The position 

 of this point above ground can be ascertained easily with the help 

 of any hypsometer. 



It might be wise to combine the Biltmore pachymeter with 

 Christen's hypsometer, so that the size of an upper diameter, as 

 well as its position, may be found by the use of a single instru- 

 ment.* 



It is evident that upper diameters can be ascertained with the 

 help of the pachymeter, without any knowledge of the distance 

 of the observer from the tree and without any reference to the 

 position of the observer above or below the foot of the tree. 



If the slot at its lower extremity, is made of double width, 

 then it is easy to find Pressler's guide point (point along the bole 

 where the diameter is one-half of the d. b. h.) directly before 

 measuring the diameter of the tree at breast-height and without 

 the use of a target and, of course, without measuring the distance 

 of the observer from the tree. 



Ralph G. Burton. 



*See eimplest method on p. 195, Vol III of Forestry QuarterIvV — Ed 



