FOREST commissioners' REPORT. IO3 



the brush seems unwise at present, or at least until paper birch 

 is much scarcer and dearer than it is now. 



Volume and Yield Tables. 



The accompanying tables show the average volume of paper 

 birch trees. The figures can not be applied to individual trees, 

 which often vary from 10 to 15 per cent from the average, but 

 applied to a large number of trees will give accurate estimates. 

 The diameters given are outside the bark. The figures are from 

 trees in central Maine and eastern New Hampshire, localities 

 which are representative of the paper birch region. All board 

 feet are by the New Hampshire log rule. 



Table 3 shows the total volume of trees of different diameters 

 and heights in cubic feet. Table 4 shows the merchantable 

 volume of trees of different diameters and heights in both cubic 

 feet and board feet by the New Hampshire rule. Table 5 

 shows the merchantable volume of trees of different diameters 

 and merchantable lengths in both cubic feet and board feet. 

 All of these tables can be applied to either seedling or sprout 

 growth. With trees of the same diameter average sprouts have 

 greater height and, therefore, greater volume than average seed- 

 lings. P>ut when they do happen to have the same diameter 

 and also the same height, then their volume is the same. In 

 other words, the shape of the stem is the same for both seed- 

 lings and sprouts, provided they have the same height and 

 diameter. If the volume tables were based on diameter alone, 

 separate tables would have to be made for seedlings and 

 sprouts, but when both diameter and height are used in the 

 classification they can be grouped together in one table, as is 

 done in this case. 



