14 Forestry Quarterly. 



It will be seen that for a 15" d. b. h, the yield is greatest and it 

 suggests that a rotation based on value increment should not 

 exceed 90 years, for after the age of 90 years the volume incre- 

 ment and in this case that means also value increment is practi- 

 cally at a standstill. 



Cut to a diameter limit of 10 inches, measurements of 30 sample 

 plots on poor rocky soil and open stand developed not more than 

 18 ties to the acre. But mature stands on good, well drained 

 soils produced in an average of 50 sample areas, taken over 

 several thousand acres, 150.5 ties, of which 17 per cent. No. i ; 43 

 per cent. No. 2, and 40 per cent, culls — a yield, which by proper 

 silvicultural management could probably be increased by at least 

 25 per cent. 



