APPENDIX j 69 



22. Spruce forest. 



a. Present practice: Natural reproduction, takes 10 years, 

 requires no artificial help ; rotation 90 years, i. e., 90 from end of one 

 reproduction to end of next; thinning needed early, 15 years after 

 reproduction is started, costs $5 an acre. 



Second thinning costs v$2 per acre at age of 25. 



Third thinning at 40 years brings $5 net. 



Fourth thinning at 60 years brings $20 net. 



Fifth thinning at 80 years brings $40 net. 



Yr at 90 years would be $600 but owing to extra cost of logging 

 is only $560. 



e is $i per acre and year, including taxes; p = 3%. What is 

 Se here? 



b. Plan is now to change this as follows : 



Plant 5 year transplants space 6x6; plants cost $3 per M, set- 

 ting costs $5 per M. 



First thinning at 20 years pays expense. 



Second thinning at 40 years pays $20. 



Third thinning at 60 years pays $40. 



Fourth thinning at 80 years pays $100. 



Yr should be $600 but heavy thinning reduces volume but raises 

 quality so that we still have $540, saving $40 on cost of logging. 



e and p same as before. What is the new Se, and how does this 

 compare to the old plan? 



23. Beech forest, site II, is not satisfactory as to income. 

 Make concrete case from Schwappach to show how this would work 

 out if changed to spruce and to pine. Put p - 3 %, e = $i, C = $10. 



24. State of Michigan has been selling land inclusive of some 

 growing stock at $i per acre. If put in pine, C = $10, e = 50 cents, 

 p = 2% and r^=8o years, how much pine must the state cut per 

 acre to beat the $i, with stumpage at $10 per M? 



25. Work out Se at 2, 4 and 5% for spruce, pine and oak, 

 all for site II; C = $io, e = $i, and r = 4O, 60, 80, 100 and 120 

 years. 



Yr and thinnings as by Schwappach. Tabulate. 



26. What is Se in coppice, rotation 25 years ; Yr 20 cords at 

 $2 ; thinnings cover expenses and taxes, planting costs $2 in each 

 rotation, i. e., at each cut; p 3%. Is this really Se? 



27. Fe, pine in North Carolina ready to cut over now, for 

 10 M. feet at $6, can return every 20 years ; e = 50 cents, soil = $5, 



= . Find Fe. 



