66 Forest Mensuration 



CHAPTER IV. LUMBER 



PARAGRAPH C. 



UNITS OF LUMBER MEASUREMENT. 



For rough lumber one inch thick, or thicker, the unit of measure, known 

 as one foot board measure, is a square foot of lumber one inch thick. 

 This unit is the i/i2th part of a cubic foot. 



For rough lumber thinner than one inch, the unit of measure, also 

 known as one foot board measure, is the superficial square foot, and the 

 thickness of the lumber is here entirely disregarded. 



All dressed stock is measured and described as if it were the full size 

 of the rough lumber necessarily used in its manufacture. "Inch flooring," 

 e. g., is actually 13/16 inch thick; and "%i inch ceiling" is actually 5/16 

 inch thick. 



Standard thicknesses are : 



it, I, I, i, it, i*, 2, 2^,3x4". 

 Standard lengths are : 

 in hardwoods 6 to 16 feet; 

 in softwoods 10 to 24 feet. 



In both cases, lengths in even feet (not in odd feet) are required. 

 A shortness of i" or 2" in the length of hardwood boards is disregarded. 

 Standard defects are : 



I. In hardwoods: one sound knot of ij" diameter; 

 one inch of bright sap ; 

 one split, its length in inches equalling the contents of 



the board in feet b.m. 

 II. In softwoods: sound knots, viz. : 



(a) pin-knots of not over J" diameter; 



(b) standard knots of not over i " diameter ; 



(c) large knots of over ij" diameter; 

 pitchpockets, viz. : 



(a) small pitchpockets " wide; 



(b) standard pitchpockets up to f " wide and up to 3' 



long; 

 pitchstreaks, viz. : 



(a) small pitchstreaks not wider than ^ the width and 



not longer than the length of board ; 



(b) standard pitchstreaks with dimensions up to twice 



as large as given under (a); 

 sap, viz. : 



(a) bright sap ; 



(b) blued sap ; 



splits, wane, scant width, tongues, less than &" long. 



