GERMAN FOREST MANAGEMENT — FOREST REGULATION. 



^w4tO 



Xormal yield table for spruce. 

 [Main growth (exclusive of thinnings) p(r acre. 



Age. 



Site okas I. 



10 years 



20 years 



30 years 



40 years 



50 years 



60 years 



70 years 



80 years , 



90 years 



100 $ ears 



Ill) years 



120 years 



N nm- 

 bei of 

 trees. 



Site class II. 



10 years 



20 years 



30 years 



40 years 



50 years 



60 years 



70 years 



80 years 



90 years 



100 v ears 



HO^ears 



120 years 



591 

 700 

 065 

 724 

 515 

 390 

 321 

 269 

 243 

 229 

 226 



2, 36* 

 1,619 



1,161 

 842 

 639 

 484 

 356 

 301 

 293 

 291 



Cross- 

 section 

 area of 

 all trees 

 breast 

 Inch. 



Sq. ft. 

 49.2 

 114.4 

 159. 5 

 188 4 

 209.7 

 225. 8 

 237.1 

 244 9 

 250 9 

 258 4 

 2C1.5 

 269. 7 



26 1 



77.9 



89.9 



151 8 



180.1 



200. 1 

 213.6 

 222.7 

 231 3 



239. 2 

 246 5 

 252 3 



Aver- 

 age 

 height. 



Wood 



above 3 



inches 



diameter. 



"Wood, 1 

 total 1 

 mass. 1 



reet. 



Cu. ft. 



Ou. ft 



4.9 



86 



715 



16.7 



1,101 



4*\ L irk 



29.2 



2,603 



4,204 



47 6 



4,748 



6,378 



62.6 



7, 222 



8,623 



76 7 



9,209 



10, 625 



88.2 



10, 582 



12, 198 



97.4 



11,655 



13,213 



105. 3 



lwf OOO 



14,043 | 



112.5 



13,299 



14, 715 



117.7 



13, 971 



15, 272 



121. 4 



14, 586 



15,730 



3 2 





415 

 1,201 



11 5 



315 



2J.0 



1,187 



2,460 



35.1 



2,502 



4,018 



47.2 



4,176 



5,791 



59 7 



6,220 



7,851 



71.8 



7, 808 



9,481 



83.0 



9,295 



10, 725 



91.5 



10,339 



11, 683 



97.7 



11,125 



12, 398 



10 i. 



11, 740 



13,013 



106.6 



12, 269 



13, 585 



Age. 



Nnm 

 ber of 

 trees. 



Site cla«s III. 



10 years.. 



20 years.. 



30 years . 



40 years., 



50 \ears„. 



60 years.. 



70 years.. 



80 years . . 



90 } ears. . 

 100 years. 

 110 years . 

 120 years.. 



3,732 



1,580 

 1,056 

 724 

 500 

 424 

 380 

 346 

 320 



Site clam IT. 



10 years. 

 20 years 

 30 \ears. 

 40 years 

 50 years 

 60 years . 

 70 t > ears.. 

 80 years. 

 90 3 ears . 



100 years.. 



110 j ears. 



120 years., 



3,164 

 1,968 

 1,276 

 864 

 648 

 554 

 500 

 464 



Cross- 







section 



Aver 



Wood 



area of 



above 3 



all trees 



age 

 height 



inches 



bieast 



diameter. 



high. 



Feet. 





Sq. ft. 



Gu. ft. 



18 3 

 53.7 



1.9 

 0.6 





100 



86.6 



15. 7 



472 



130.1 



25.6 



1, 244 



154.9 



36 7 



2, 574 



171.8 



48.2 



4,004 



185 3 



59.0 



5,219 



196.2 



67.9 



6,220 



205 2 



74.1 



7, 093 . 



214 9 



79.4 



7, 922 



223 2 



88.0 



8,694 



230. 6 



85.6 



9,324 



11.3 

 30 5 



72.2 



1.6 



4.6 



10 5 







140 



107.9 



18.0 



515 



130. 1 



26. 2 



1,287 



143. 5 



35.1 



2, 231 



154. 9 



42.6 



3. 089 



162 6 



51.5 



3,790 



172. 3 



57.1 



4,361 



181 5 



61.3 



4,848 



187.0 



63. 3 



5, 305 



191.4 



66.6 



5,720 



Wood, 

 total 

 mass. 



Cu. ft. 



200 



772 



1,G17 



2,760 



4,247 



5, 634 



6,893 



7,994 



8,866 



9, 638 



10, 296 



10, 725 



157 



500 



1,044 



1, 830 



2, 788 

 3,761 

 4,519 

 5, 248 

 5,763 

 6,249 

 6,707 

 7,150 



In very regular growths trial areas only are measured. The more usual manner of deter- 

 mining the rate of accretion, however, for purposes of yield calculation, is by felling sample trees 

 of each class, dissecting and measuring the accretions of past periods. 



In modern times the exact measurements are mostly confined to the growths that are utilized 

 during the first or first two periods of twenty years. 



FELLING BUDGET. 



After all these data for each compartment have been booked, and the yield of branchwood 

 and roots — for even these are mostly utilized — as well as the probable amounts -co be taken out in 

 thinnings, have been estimated and recorded, and after the likelihood of decreased accretion 

 in the different compartments has also been determined from measurements and experience, the 

 " felling budget" is determined as a sum of the stock on hand and the amount of annual accretion 

 multiplied by the time, during which it is allowed to grow, i. e., in the average to the middle of 

 the period in which the compartment is placed, divided by the period of rotation. Thus a growth 

 of eighty-five years, which showed a stock on hand of 3,825 cubic feet per acre, and hence had an 

 average accretion hitherto of 3,825 ~- 85 = 45 cubic feet per year, which is likely to be reduced on 

 account of gradual reduction in stock and other untoward conditions to 30 cubic feet, would yield 

 during the first period 3,825 + 30 x 10 == 4,125 cubic feet. And if the compartment contained 50 acres 

 it should be credited in the working plan in the column for the period I with 4,125 x 50 = 206,250 

 cubic feet. By adding up the amounts of the yield of all the compartments placed in the first 

 period and dividing by 20 (the length of the period) the annual budget which should be felled 

 during the period is found. If, however, it is desired to equalize the fellings more or less through 

 a longer period — for instance, the time of rotation— then the amounts in all the periods must be 

 summed up, and these sums as nearly as possible equalized by shifting the position of the com- 

 partments from one period into another (necessitating always new calculations of the accretion) 

 until the equalization in the periodic sums is effected. 



Even then, however, before finally determining the annual budget, a calculation is made to 

 see whether the area contains as much timber as it normally should; if more, the budget may be 

 increased; if less, a saving must be made in order to bring up the stock on hand to the normal. 

 If, for instance, we know from the experience tables that our forest should normally yield 50 cubic 

 feet per acre a year in a 100-year rotation, then the normal stock would be 100x50-~2=2,500 cubic 



