152 A MANUAL FOR NORTHERN WOODSMEN 
tence of sawyers is one cause of this, and that, according to 
careful mill men, may readily amount to 10 per cent. Then 
market demand affects the matter, some mills being so 
situated that they can market only the larger sizes of lumber. 
The type of saw employed and the methods of handling 
on the carriage also have their effect. 
TABLE I 
Yield in inch boards, squared, of second growth white pine 
logs. Based on 740 logs; study by Harvard Forest School. 
Growth extra tall and smooth; large and small trees in 
the stand, which was cut clean; logs with 2 in. crook or 
over thrown out. Sawed by circular saw cutting ^-inch 
kerf. In scaling, fractions of inches up to .5 were thrown 
off, fractions of .6 and over taken as if of inch above. 
Boards merchantable down to 2 feet, surface measure; 
some wane allowed. 
Top 
Diameter 
Yield B.M. 
12-foot Logs 
14-foot Logs 
5 inches 
14 
15 
6 inches 
20 
23 
7 inches 
26 
30 
8 inches 
34 
39 
9 inches 
43 
50 
10 inches 
53 
61 
11 inches 
67 
76 
12 inches 
81 
90 
13 inches 
95 
105 
14 inches 
110 
122 
15 inches 
128 
139 
16 inches 
147 
160 
17 inches 
170 
18 inches 
202 
A practice that in some localities of recent years has 
greatly increased the merchantable product of logs is that 
of sawing waney or round-edged boards. Portable mills in 
southern New England sawing lumber for boxes or finish 
follow this practice largely, and stationary mills in many 
localities have a box or other saw to which they can turn 
over the small and crooked logs for this most economical 
