MILIv SCALE STUDIES. 



Trees increase in value as they increase in size. This increase 

 is due to the increment in the quantity of wood, and, to a much 

 greater extent, to the improvement in its quality. The following 

 table is based on actual measurements : 



Proportionate increase in wood quontily I, 2, 3, 4, 5, 6. 



" " " " in the value of the tree i, 2>^, 4, 6, 8, 10. 



In other words, one tree containing three times as much lumber 

 as another, was worth four times as much as the first ; one con- 

 taining five times as much lumber, was worth eight times as 

 much, and so on. 



To determine as accurately as possible the rate of appreciation 

 the Forest Service has been conducting a series of experiments 

 known as Mill Scale Studies. 



The method followed is to measure each tree as it is felled in 

 the woods, record the measurements, mark each log so that it 

 may be identified at the mill, and measure and inspect every 

 board sawed out from the identified logs. The quantity and the 

 grades of lumber from each log are recorded on a separate sheet, 

 and by bringing together the sheets corresponding to the various 

 logs of any given tree the exact amount and the quality of lum- 

 ber obtained from that tree are ascertained. 



The difficulties which beset such a study are numerous, and 

 some of them seem to be insurmountable at present. A few of 

 them will be pointed out in this paper, and remedies suggested. 



There are two classes of factors which affect the quantity and 

 the quality of the lumber of any tree, ( i ) natural, and ( 2 ) arti- 

 ficial. 



A study of the specifications for grading lumber shows that 

 the four main factors which affect the quality of a board are its 

 width, the proportion of sap to heartwood, the presence or ab- 

 sence of knots, and pathological defects. 



In any given stand, the width of the boards that may be cut 

 from a tree, the proportion of sapwood, and the clearness of the 

 wood are all dependent on the diameter of the tree. Generally 

 speaking, the bigger the tree, the wider, clearer, and less sappy 

 are the boards obtained. Since the diameter, however, is a func- 

 tion of the density of the stand, the first three factors mentioned 

 will largely depend on the density of the stand, and a mill scale 



