324 DETERMINATION AND REGULATION OF THE YIELD. 



Supposing, that the real growing stock is greater than the 



r X / 



normal : ^„r,,„, = — - — + ./• ; then. 



r r 



2 2 



more than the increment will be cut, so that the surplus of 

 growing stock will gradually disappear. 



All these assumptions depend, however, on the supposition 

 that the normal increment is laid on. If the increment is 

 deficient, the abnormal state may be further increased, until 

 the increment has reached its normal size. 



The merits of the method are approximately those of 

 Hundeshagen's method. It introduces an additional inaccu- 

 racy by being based on the assumption, that the normal 



I X r 

 growing stock is = — - — . On the other hand, the normal 



A 



growing stock and normal yield need not be determined ; in 

 other words, the method can do without yield tables. It is 

 only necessary to measure the growing stock, and to determine 

 the rotation. 



The method is very simple, and it is specially suited for 

 determining the yield of selection forests. 



4. Brandis' Method. 



The method to be described under this head will be best 

 understood by indicating the circumstances, which lead to its 

 elaboration. 



Doctor (now Sir Dietrich) Brandis, on being appointed 

 Superintendent of the Pegu forests in Burma in 1856, found 

 himself confronted by enormous areas of teak forests in 

 danger of being heavily overworked. These forests contained 

 teak in varying proportions, but on the whole to a limited 

 extent, which has since been ascertained to amount to perhaps 

 10 per cent., while about 90 per cent, of the growing stock 



