QUALITY OF WOODS. 267 



if the yield is fixed for a whole rotation, or when the increment 

 forms the principal basis for the determination of the yield. 

 In the latter case both normal and real increment must be 

 ascertained. AVhen the yield is fixed for only one, or at the 

 outside two periods, the current increment must be ascertained 

 for that number of years, or the mean annual increment of the 

 past is substituted for it. 



For financial questions the quantity-, quality-, and price- 

 increment must be determined, as well as the capital invested 

 in the forest, so as to calculate the indicating or forest per 

 cent. The latter is necessary only for woods, the financial 

 ripeness of which is doubtful, that is to say, for woods which 

 are approaching the normal final age, and woods which have 

 suffered by injurious agencies, such as wind, snow, fire, insects, 

 damage by game, etc. 



3. Determination of the Quality of each Wood. 



a. General. 



Under the quality of a wood or compartment is understood 

 its yield capacity, as expressed by the quantity of produce which 

 can be derived from it. 



The yield capacity depends in the first place on the locality ; 

 but injurious influences may have interfered with the full 

 development of the producing factors of the locality, so that 

 abnormal conditions may be the consequence. The forester 

 distinguishes therefore between normal and abnormal quality. 

 The quality is normal, if no extraordinary injurious influences 

 have affected the development of the wood. 



A further distinction must be made between the quality of 

 the " locality " and of the " growing wood " or standing crop. 

 Either of the two can be normal or abnormal. The quality of 

 the locality may be abnormal in consequence of a variety of 

 causes, such as the continued removal of litter, or excessive 

 exposure to the effects of sun and air currents which have 

 impoverished the soil ; or in consequence of unfavourable 



