THE THEORY AND PRACTICE OF WORKING PLANS 201 



soil-rent values checked by actual sale values. The prescribed 

 interest rate is 2.5 per cent. While — quite properly — the man- 

 agement is not to be based upon a strict calculation, the prin- 

 ciple is laid down, that the aim of the management is to be to 

 secure the highest forest net income possible under sustained 

 yield management besides at the same time attempting to 

 secure an adequate interest rate on the capital involved in the 

 management. 



Hence, stands are to be considered ripe when the periodic 

 increment of the forest net yield begins to decline considerably, 

 and to determine this rotation, forest net yields and average 

 interest calculations are to be made, also soil expectancy values 

 with interest rates of 1.5 to 3 per cent are to be calculated to 

 exhibit the time of culmination. 



If then the rotation based on the forest rent and the financial 

 rotation based on an " adequate " (if no special considerations, 

 2.5 per cent) interest rate coincide, it is accepted. If not, then 

 investigation is to be made to see by what changes in manage- 

 ment coincidence can be secured. 



In this way, for the first time, at least a financial check is 

 introduced. 



Where the determination of the rotation in this way leaves 

 uncertainty, the index per cent, or with very valuable stands 

 only the value increment per cent, is to be used for judging 

 ripeness. 



Rules of management for districts of similar conditions of 

 production are to be formulated to stop the continual experi- 

 menting of each manager. 



For regulation of the cut the stand method (method No. 16) 

 has been adopted. 



The securing of normal age-class distribution in area and 

 volume is to be especially attempted. 



In very uneven-aged stands or with long periods of repro- 

 duction, a comparison between actual and normal stock is to 

 be used as a check with Heyer's formula (method No. 9), or 

 else the volume rate per cent may be used as a check. 



