98 



PRACTICAL FOREST MANAGEMENT. 



Calcula- 

 tion of the 

 yield of a 

 forest by 

 formulae. 



An actual example from the Chuka Working Circle of Pilibhit 

 division is given below : 



P. B. I. Chula Circle, Pilibhit Forest division. 



Annual yield- 



_6,P61,626+(296,693X15) 



30 

 _ 6,961.626+4,450245 



80 



_ 11.411,871 

 30 



i.e., annual yield= 380,396 cubic feet = 380,000 c. ft. in round 



figures. 



NOTE. C. A. I. of trees over 20* diameter is neglected, nince these are overmature, nd any 

 possible increment will be counterbalance! by probable decrement (windfalls, decay, 

 trees drying up, etc.). 



There are two points in forest management in India which 

 have a very material effect in the determination of the yield of 

 a forest. There is first the practical impossibility of enumerating 

 the growing stock of a forest down to seedlings, actually for the 

 United Provinces working plans, enumerations are seldom carried 

 down below trees of 8* diameter. The second point is the rela- 

 tively high definition of timber, which,, for research work generally, 

 and for all forests, where sawn or large timber is the object of 

 management, has been defined as measured down to 8" diameter 

 over bark. Thus in the United Provinces forests generally, the 

 real growing stock (V) represents timber over 8" diameter only, 

 and is ascertained by enumerations of trees o\er 8" diameter (in 

 standard 4* diameter classes), the numbers of trees in each diameteir 



