CALCULATION OF THE ROTATION FOB CONIFERS IJs KULU. 93 



diameter of 12" the increment gradually rises from '16 to '30 

 at a diameter of 18'' and '49 at 26" corresponding to a rotation 

 of 120 years. Even now this increment has not reached its 

 maximum but increases to '52 at a diameter of 28" remains the 

 same for 29' / and then commences to decline. If the figures of 

 the current annual increment calculated on the volumes of trees 

 on which the yield is based are examined, it will be seen that 

 trees of diameter 12 // to 18" having an average volume of 30 c. ft. 

 and being of an average age of 66 years produce an annual 

 increment of 1'27 c. ft. This increment increases to 1'48 in 

 the trees of diameter class 18" to 24" and reaches its maximum 

 of 2 00 in the diameter class 24* to 26' / . Hereafter it declines 

 to 1 ' 50 in the diameter class 27" to 29' / and to 43 in the 

 diameter class 30" to 32". As a rotation of 295 years has now 

 been exceeded no useful purpose is served by continuing this 

 investigation. Indeed an examination of the thousands of 

 statistics on which these calculations are based show that the 

 average tree does not attain a diameter greater than 32". 



' It is now necessary to consider the bearing of compound 

 interest on the values of trees at different ages. First of all the 

 current sale value of the trees and the amount being received for 

 their cubical contents may be examined. A deodar 18" and 

 over but less than 24" in diameter yields 67 c. ft. of the value 

 of Es. 7-5 a value of 1'79 annas per c. ft. A I class tree 24" 

 to 26" is worth Es. 22 '5 or 3 -42 annas per c. ft. and similarly 

 the class 27" to 29" is worth 3' 5 annas and the class 30" to 32" 

 3 '59 annas per c. ft. respectively. It is thus evident that the 

 current prices for I class trees are approximately 3 50 annas 

 per c. ft. and it will therefore suffice to adopt actual prices 

 now being received for the trees in considering this aspect of the 

 matter. 



" A II class (18" 23") tree enters this class at the age of 80 

 years and reaches the I class (24" 26") at the age of 110 years : it 



