SIZE OF THE AGE CLASSES. 21 1 



and the age-classes : 



Blanks : none. 



C'l ( 1— 20 years oM woods) =rXii = 10x'20= 200 acres. 

 C2 (21— 40 „ „)=„=„= 200 „ 



C'3 (41— 60 „ „)=„=„= 200 „ 



C4 (61— 80 „ „)=„=„= 200 „ 



C's (81—100 „ „)=,,= „= 200 „ 



^=1,000 acres. 



//. Shellpr-ii'ooil Compartment Si/stfm. 



As already explained, under this system the old crop is 

 gradually led over into a young wood in the course of a 

 number of years, which has been indicated by m. There is 

 always an area under regeneration, which contains a certain 

 number of old trees and young growth, and this may be called 

 the regeneration class = C\,; it wanders gradually through the 

 whole forest, until, at the beginning of the second rotation, it 

 is found in the original position. As regeneration in some cases 

 takes only a few, and in others more, years, it is impossible 

 to define its duration accurately, and least of all can m be 

 placed equal to n, the number of years in the period. Under 

 these circumstances, the arrangement of age classes can 

 be indicated only approximately, somewhat in the following 

 manner : — 



Cuttings in the oldest age class commence, when the crop 



is r — — years old, and the last cuttings occur, when the crop 



is ?■ + ^ years old ; then the annual cutting area, as before, 



= — , and the area of the regeneration class =— x w. If 

 r r 



m<^)i, then the regeneration class contains areas as vet 



blank, young trees from 1 to m yeai-s old, and the remaining 



old trees up to r + - years old. It forms part of the 



n 



p2 



