Periodical Literature. 477 



the understand (par le has) vary irregularly and differ very little, 

 while in d and e, i. e. thinnings in dominant and selection thin- 

 nings which were made in a few cases did not show much better. 

 The total average showed 



Thinning degree a b c d e 



Valuemeters 100 98 102 106 92 



Increment per cent 4. 4.1 4.5 4.5 4.9 



The thinnings in the subordinate stand of pine showed also no 

 tangible result, the increment per cent for a, h, and c thinnings 

 being 4., 4.1, 4 respectively, the volumes 96, 100, 96. 



A much more satisfactory experiment with different methods 

 of calculation was carried on by the author independently in 

 beech. The procedure started with the thought that a thinning 

 produces two effects: an increase of increment on the remaining 

 stand which is expressed by the difference of the increment per 

 cent of the thinned stand {s) and that of the unthinned main 

 stand (3') ; and on the other hand, an earlier money income which 

 can earn interest (p) instead of the increment per cent (x) of 

 the subdominant stand of the unthinned stand, so that, if the 

 original dominant stand was H, the thinned stand D, a precise 

 financial expression of a thinning would be: ^^=H(c — y) 

 -{-D (p — x). In practice, recognizing five stem classes, the per- 

 formance of each of them would have to be ascertained and the 

 sum found. 



The three experimental areas were thinned every 5 years, alto- 

 gether 5 times (original ages 6y, 67, 63), the first one, with thin- 

 nings in the subdominant, tree classes I-III ; the second, by selec- 

 tion thinning, tree classes III-V; the third one by thinning in 

 the dominant, tree classes II-IV. A fourth area lightly thinned 

 was used to determine increment per cents 3; and x of the form- 

 ula, while the increment per cent s of the thinned stands was for 

 each stem class in each area calculated from the 20 year period. 

 The following results appear. 



Stem class I II III IV V 



X or y 3 2.2 3.3 3.6 3.8 



2: in area 1 1.2 2.1 3.6 4.3 3.9 



z in area 2 2.4 ^.6 3.8 3.5 3.1 



z in area 3 1.5 3.6 4.6 3.9 4.1 



