24 Forest Mensuration 



of the angle found between the horizon and the probable sight to the 

 "guidcpoint" (at which the observer expects to find one-half the diameter 

 chest-high). Thus, actually, the instrument merely examines the correct- 

 ness of an original estimate. 



The Pressler telescope can be used for finding the merchantable length 

 of any bole. Merely place a stick, equal in length to twice the minimum 

 diameter permissible in a merchantable log, at the foot of the tree, catch 

 it between the nail points and proceed as described. 



PARAGRAPH XXXVII. 



AUXILIARIES FOR CALCULATION. 



Auxiliaries for calculation are : 



1. Sectional area tables (Schlich, Vol. III.) ; engineering books like 

 Has well's; Bulletin 20; also Green.) 



2. Ideal cylinder tables (Schlich and Bulletin 20). 



3. Multiplication tables and logarithm-tables. 



4. Tables showing contents of logs in any of the 43 rules, according 

 to length and diameter. 



PARAGRAPH XXXVIII. 



TREE VOLUME-TABLES. 



Tree volume tables have been constructed on a very large scale for the 

 leading species in the old country. In the United States, the Government 

 is now beginning to make such tables. The tables give the cubic, lumber 

 and cord wood contents of trees, according to species, diameter and some- 

 times according to total height and merchantable height (number of logs). 



Bulletin 36 reprints the following tree volume tables : 

 A. According to diameter measure merely. 



Page 92. Adirondack White Pine, volume in standards. 



Page 94. Pennsylvania Hemlock, volume in feet, b. m., Scribner. 



Page 94. Adirondack Hemlock, in standards. 



Page 95. Adirondack Spruce in standards. 



Page 96. Adirondack Birch, Beech, Linden, Sugar Maple in Scribner, 

 feet, b. m. 



Page 96. Adirondack Balsam, in standards. 



Page 97. Adirondack White Cedar, in standards. 



Page 98. Arkansas Shortleaf Pine, in feet, b. m., Doyle. 



Page 98. Missouri Ash, Elm, Maple, Cypress, Gum, Oak, Hickory, 

 Poplar, in feet, b. m., Doyle. 



Page 99. Western Yellow Pine, in feet, b. m., Doyle (Black Hills), dis- 

 tinguishing between the volume of first and second growth. 



Page 99. Yellow Poplar in Pisgah Forest in feet, b. m., Doyle, distin- 

 guishing between good, average and poor conditions of 

 growth. 



