124 THE MANAGEMENT OF WOODLANDS. 



England, though practically here a number of annual falls is 

 grouped together to form a periodic fall according to the interval 

 occurring between any two successive good mast years. But 

 with regard to Conifers and other high woods formed without 

 any definite scheme of management having been kept in view, 

 as,, has often been customary in Britain, one must fix the 

 rotation, estimate the growing-stock required, and then de- 

 termine the area to be felled annually in order to maintain a 

 continuous and regular income from the woods. The annual 

 fall can be determined by one or other of the methods based 

 upon (1) the woodland area alone; (2) the yield or cubic contents 

 of the crops; and (3) by a combination of the area and the 

 yield. For easy supervision in each of these three methods, the 

 annual falls can be conveniently grouped into periods or periodic 

 falls, each comprising the annual falls of 20 years ; and more 

 particular attention is devoted to falls in the first half of the 

 oldest or I. period than to those in the second half, or in the 

 II. or subsequent periods. With a rotation of 100 years there 

 will be 5 periods, I. including the oldest woods, 81 to 100 years, 

 II. those of 61 to 80, III. 41 to 60, IV. 21 to 40, and V. those 

 up to 20 years old. And the I. period would be divided into 

 the two sub-periods, I 1 , and I 2 ., respectively denoting woods 

 of 91 to 100 years and 81 to 90 years ; while the remaining 

 periods need not be so subdivided. 



(1) Fixing the Annual Fall from the Woodland area alone 

 is the oldest 'and simplest method, the whole area being divided 

 equally into the number of annual falls needed for the rotation, 

 and the area in each case being therefore equal to the total 

 woodland area divided by the number of years in the rotation. 

 The great drawback .to this very simple method is that it does 

 not allow for differences in soil-productivity or as to .the 

 distribution of the growing-stock in the properly proportionate 

 : age- classes ; hence, in order to ultimately equalise the areas 

 felled in each period it might be necessary to cut some crops 



