NOTES. 



463 



Hunonio 



cuatc rt 



ISO 



leo 



140 

 120 



too 



60 



eo 



40 



180 



leo 



140 

 ISO 

 100 



80 . 



80 



40 



30 



10 20 30 10 50 60 70 60 80 100 UO 120YEARS 



Diagram showing comparative progress of yields of spruce, fir, pine, 

 and beech, on best and poorest site classes. 



classes may be stated as follows, leaving out the yield in the 

 thinnings, which may amount to as much as 40 per cent of 

 the final harvest : — ■ 



Site Class 



III. 



IV. 



Scotch Pine. 

 Norway Spruce . 

 Silver Fir . . 

 'Beech . . . 



cu. ft. 



93 

 154 

 158 

 to6 



cu. ft. 



70 



127 



128 



8s 



cu. ft. 



56 



99 

 102 



70 



cu. ft. 



45 

 78 



n 



5° 



cu. ft. 



35 

 56 



35 



By multiplying this average increment by 100, the years 

 of rotation (or any number of years near that rotation), the 

 total possible harvest per acre is obtained. It appears that 



