72 



taken; but in India, in the ease of selection fellings, 25 

 years or more have sometimes been found expedient. An 

 interval of time varying from 10 to 30 years would, there- 

 fore, generally be that within which the prescriptions 

 would run. 



(«*) Area operated on. — The area or coupe to be operated 

 on each year may be determined by dividing the number 

 of acres in the whole forest, less blanks, etc., by the number 

 of years in the felling rotation, and then by apportioning to 

 each block or natural sub-division, according to the fertility 

 of the soil, a certain number of coupes each of that area. 



The following example will explain this process. Suppose a forest of 3,870* 

 acres oontaining a crop insisting of three types, only one of which is at present 

 pTodactive owing to the others containing no !>aleahle species ; also that four blocks 

 bounded by roads, rivers or other landmarks, hare been formed and analysed as 

 follows : — 



We will assume that the felling rotation adopted is 15 years, and that it is 

 consequently required to divide ihe total area into 15 poitions of egnal forest 

 productivity. This may be done as follows : — 



Total area of forest 3,870 acres 



Deduct blanks and nnezploitable areas . . 87o 



Total exploitable area 



if.OOO 



The average area to be operated on annually is ^=j^= 200 acres. In order to lay 

 out these areas each block may be divided into an integral number of coupes contain- 

 ing an area of exploitable forest greater or smaller than the average acoordinjt to 

 fertility of the soil. Thus, Paimar, Datwind and Haigla, containing very cood 

 fertile soil at the base of the hills, might each be divided into coupes contaiuins on 

 an average, less than 200 acres of sfil forest ; whilst Baira, sitnatod iu rocky ground 

 m the bills where the quality of the soil is poor, might be divided into five portions 



■ * It neodlardly be explained that small areas of unexploitable forest would be included 

 where necessary in a working-oirole. 'uviuuou 



