258 Forestry Quarterly 



The above shows that : 



a) With a reasonable technical rotation (90 years and over) 

 the interest actually made by the growth of a normal forest of 

 spruce on good land is 3.3 per cent or less ; 



b) With a rotation of 120 years the influence of planting costs 

 and current expenses becomes almost trivial. 



Interesting, in this connection, are the following figures : 



Interest Rate Made by the Normal Forest of Different Species, 

 ON Sites I-IV Regulated to a Rotation of 120 Years 

 Pf={Yr+XTq-c-re)100 



These figures indicate that the sites do not materially affect 

 the per cent made. 

 Summing up: 



1) The normal forest of Central Europe, in ordinary rotations, 

 makes between 2 and 3 per cent on the sale of the forest ; 



2) The rate made by the forest is quite independent of site; 



3) Beech and oak exceed pine and spruce in the rate made in 

 a 120-year rotation, not by a better income, but by a smaller 

 value of the growing stock in young stands and consequently 

 less value of G^ , the important part of the capital; 



4) The rate made by a forest varies within narrow limits for 

 all reasonable rotations, and is little affected by current ex- 

 penses ; 



5) The rate does not vary materially with changes in price of 

 timber, since such changes affect capital and income alike; 



6) Extensive forestry, with small expenses and small incomes, 

 will produce as good a percent (for ordinary lands and rota- 

 tions of 100 years and over) as intensive forestry, but the in- 

 come and capital are both smaller, and such a forest does not 

 fully perform its public duties ; 



7) In farming a reduction in the sale value of the land (farm) 

 radically affects the per cent made by the farm. In forestry the 

 usual values of the land are, with ordinary rotations, of little 



