36? Forest Management 



tween the normal growing stock (Ng) and the actual growing stock 

 (Ag). 



Ng AG 

 P = S - 



n 

 "n" is the number of years forming the installation period. 



The field work in this method is timestaking; especially so under 

 the selection system or group system when the actual growing stock 

 can be ascertained only by complete valuation surveys. On the other 

 hand, the method prevents any over-cutting or any under-cutting of the 

 forest, and shows clearly how much of the revenue obtained is, in fact, 

 net revenue and not capital withdrawn, or else, how much of the reve- 

 nue is left latent being used to increase the original growing stock. 

 This method is well adapted for irregular forests. The method re- 

 quires: 



1. A detailed description of compartments giving the normal and 

 actual volume, and the normal and actual increment for each compart- 

 ment. 



2. A statement showing the normal growing stock, the actual grow- 

 ing stock, and the total increment for the period of installation. 



3. A statement enumerating the compartments in which the possi- 

 bility is to be cut. 



No particular stress is put on reaching a normal gradation of age 

 classes. 



PARAGRAPH XXII. 



HUNDESHAGEN METHOD. 



Hundeshagen assumes that the ratio existing between the incre- 

 ment and growing stock is constant. With the help of yield tables, he 

 ascertains the ratio existing between normal increment and normal 

 growing stock and, further, the actual growing stock found in the for- 

 est. Multiplying the actual growing stock by the above ratio, Hun- 

 deshagen obtains his actual annual possibility of the forest. 



In normal forests (yield table forests), the ratio is necessarily at 

 an optimum. If that optimum is applied to abnormal forests, over- 

 cutting seems the necessary consequence. Absurd results are apt to 

 crop out if the growing stock is under normal and the increment poor. 



Inasmuch as the method requires periodic stock taking, over-cut- 

 ting or under-cutting the forest for any length of time is, however, 

 excluded. Indeed, any method is good which controls its own results 

 by periodic stock-taking. Hundeshagen's method is applicable to all 

 sorts of silvicultural conditions, and might well be applied in a tentative 

 first working plan. In that case, it will be sufficient to express the 

 ratio, "normal increment over normal growing stock" by the frac- 



2 



tion . 

 n 



