95 



part been so overfelled and mal-treated that they contain 

 little or no sound mature stock ; and where the crops have 

 not been mal-treated, there is generally no demand for any 

 but the principal species. 



Length of the felling rotation in selection-worked forests.— 

 It will have been seen that the application of the possibility 

 involves the determination of the felling rotation ; and, in 

 fact, the first step towards introducing order in the working 

 consists in restricting the locality to be worked over each 

 year or period to a definite area. The object of this is to keep 

 the extent of each separate felling within manageable limits ; 

 to conduce to effective supervision of the work ; and to ren- 

 der the extraction of produce easier and less expensive. 

 Theoretically, every acre of the whole area ought to be 

 worked each year by the removal of the exploitable trees. 

 But this would not be practicable ; as the trees to be felled 

 would be scattered over so large an area that it would not 

 be profitable to remove them. It is, therefore, necessary to 

 decide what time may be allowed to elapse between succes- 

 sive fellings in the same place, and, having determined this, 

 to divide the forest into a corresponding number of coupes, 

 one of which will be exploited each year or period. 



Where the possibility is calculated by the usual Indian 

 methods and prescribed by number of trees, it may be found 

 convenient to make the length of the rotation equal to, or a 

 sub-multiple of, the average number of years required 

 for trees of the lowest girth of the second class to attain the 

 lowest exploitable size. In other cases it may be found 

 that the felling rotation should, in order that the working- 

 plan may be as simple in construction as possible, be a sub- 

 multiple of the exploitable age. This can easily be done 

 by slightly enhancing or reducing the calculated exploitable 

 age. There is nothing wrong in such an adjustment ; for 

 it is ridiculous to suppose that the calculated rate of growth 

 is so accurate that a variation of a few years either way will 

 make any material difference. 



Within limits, it is a matter of comparatively small im- 

 portance from a sylvicultural point of view at what intervals 

 of time fellings are repeated in the same area. With a short 

 as compared to a longer interval, the area gone over at each 

 felling is larger, and the quantity of produce removed is less 

 per unit of area ; while the crop has a shorter time in which 

 to recover from any injurious effects attributable to the 

 operation of felling. Practical considerations, as regards 



