INCREMENT, GROWING STOCK AND YIELD. 



annual increment is substituted for the mean annual increment, 

 provided the calculation is made for the rotation, when the 

 normal growing stock calculated from a yield table is equal to 

 that calculated by the mean annual increment. For all other 

 rotations deviations occur, as the following example will 

 show : 



For a rotation of 100 years Cubic feet. 



Annual increment of all age gradations . . = 5,580 

 Total in 100 years = 558,000 



Total yield in 100 years = 558,000 



Normal growing stock in middle of summer, taken 



from yield table =320,000 



Increment laid on by old growing stock 



- 558,000 - 320,000 = 238,000 

 new =558,000-238,000 = 320,000 



2. Allotment of Increment during the Regeneration Period. 



It is of interest to know, in the case of the shelter-wood 

 compartment system, how much of the increment laid on 

 during the regeneration period on the area under regeneration 

 goes to the old growing stock, and how much to the new. For 

 this purpose it may be assumed that the old wood is removed 

 in the course of m years by annuall} 7 equal instalments, and 

 that the cuttings are made in the commencement of the 

 year. Total annual increment = I; the allotment is then as 

 follows : 



Allotment of Increment to 



Old Stock. New Stock. 



During the first year (^zl) x 7. - x 7. 



m m 



second (^Z2) X J. 2 x7. 



m m 



m 



x/=0. 



