'92 PRACTICAL FOREST MANAGEMENT. 



Moreover, from what has been written in Chapter VI, it is probable 

 that stl will not persist as a fully stocked crop to a greater age, 

 and the undoubted factor of rot and hollow more than counter- 

 balances any possibility of price increment. 



" A rotation of 96 years (including 10 years for establishment 

 of seedlings) will give the following mean crop diameters : 

 Quality II .... 16" 

 III .... 13" 



' These diameters are the average of the crop ; the best trees 

 will be considerably larger, e.g., over 20* diameter on reasonably 

 good sites. It is doubtful if fully stocked healthy crops of a 

 larger mean diameter can be grown under the growth conditions of 

 this locality. 

 The rotation for this working circle is therefore fixed at S6 years." 



Where yield tables have notjyet been prepared as for cliir and 

 deodar, as well as in the case of selection forests and standards in 

 a coppice, we are compelled to fall back on the volume tables for 

 individual trees and to make a comparison of the ages, volumes 

 and value of average trees of the different diameter classes, 

 comparing the amount realisable at each age on the one hand by 

 felling the tree and on the other hand by preserving it. By felling 

 the tree its price can be placed out at compound interest ; by 

 preserving it the tree would acquire an additional value with 

 increased size. The two figures so obtained for different rotations 

 can be compared, when it is at once seen whether it is profitable 

 to fell the tree or keep it standing to a longer rotation. As 

 an example the method of calculating the yield of the Regular 

 Working Circle of the Kulu plan is given below. 



40 " From the statistics given in the volume tables it is possible 

 tion of the to obtain all figures necessary to the calculation of the rotation for 

 rotation deodar. First of all if the mean annual increment in cubic feet 

 conifers * sawn scantling be examined, it will be seen that starting from a 

 in Kulu. 



40 Kulu Working Plan. -TREVOR 



