THE THEORY AND PRACTICE OF WORKING PLANS 



219 



(3) Both the average age and the age limits are given. 

 The table of age-class distribution takes the following form: 



A separate age-class table is prepared for each " Betriebs- 

 klasse " (working group). 



Areas in process of reproduction are entered in full in Column 

 14. But, if the cutting is shelterwood, the proper propor- 

 tions of the areas appear also in the age class (Columns 4-12) 

 so as to show the existing proportion of old timber, young growth, 

 and blanks. 



Below the actual area of each age class, the normal area 

 thereof is entered for the purposes of comparison. 



(4) As index to the yield the following factors are entered: 



(a) The average height of the stand. 



(b) The sum of the basal areas. ^ 



(c) The site quality and species occupying it. 



(d) The present density in tenths of 1.0 = fully stocked. 

 Stands are to be considered fully stocked if the actual volume 

 per hectare corresponds to the volume given in the yield table 

 for the same age, site quality, species, and silvicultural method. 



