FOREST ECONOMY. 217 



interest to state that for nearly forty years a fierce 

 literary battle as to the propriety of applying either 

 one or the other method has been waged in the 

 German forestry literature between the adherents 

 of the forest rent and the soil rent theory of finance 

 calculation. 



Where, as in the selection forest, the harvest is 

 made by selecting trees here and there, as they 

 grow to suitable size, instead of determining a rota- 

 tion which covers the whole time from the seedling 

 to the harvest stage, a calculation may be made 

 which determines only the last part of the rotation, 

 namely, the time which is required by trees near 

 cutting size to grow from one diameter class into 

 the next higher, and then choose that diameter 

 limit for cutting which appears most profitable 

 the exploitable size. Since this method of 

 ascertaining a conservative felling budget is ad- 

 vocated and used in the so-called working plans 

 prepared by the United States Bureau of Forestry, 

 it may be well to elucidate it more fully. It was 

 first taught in 1746 by the German forester Oettelt, 

 and adopted with various modifications by the French 

 Code forestier, and later by the Indian Forest De- 

 partment, as paving the way for better methods. 



By a forest survey, the number and contents of 

 trees of different diameters near felling size found 

 on the average acre is ascertained ; by a series of 

 measurements (stem analyses) the rate at which 

 one diameter class grows into the next higher is 



