188 



PRINCIPLES OF AMERICAN FORESTRY. 



TABLE SHOWING PERCENTAGE OF ACTUAL VOLUME 

 OF LOGS ON WHICH THE SELLER GETS RETURNS 

 ACCORDING TO SCRIBNER'S RULE. 



his work. Where there has been a survey of land by the 

 government, as is common, he will not be called upon 

 to make one, as maps sufficiently reliable for his purpose 

 may be had from official records; but to meet all the re- 

 quirements of his position, the forester should be an 

 expert surveyor, and provided with all the necessary instru- 

 ments for the work, including drawing instruments, tables, 

 stationery, etc., for office work, in mapping and platting 

 his field observations. The work of forestry mensuration 

 is concerned mainly with taking diameters and heights of 

 trees, determining the areas on which they stand and the 

 rate of growth. 



