GERMAN FOUKST MANAGEMENT SILVICULTURE. 



253 



Since it is observed that in the struggle for existence among the individual trees there are 

 quite early some trees getting the advantage and becoming dominant, it is interred that thinnings 

 are most effective in the earlier period of the crop. 



In discussing the degree to which the thinning is to be made, a classification of the trees 

 according to the character of their development is made by German foresters as follows : 



Domiuaut or superior growth. 



Dominated or inferior growth. 



l.'laui I. Predominant trees with highly developed crowns. 



I'liixx :. Coilomiuaiit trees with tolerably well developed crowns. 



Clans S. Subdommant trees with normal crowns, hut poorly developed and crowded 



above. 

 Clans -1. Dominated trees with crowns poorly developed and crowded laterally. 



(a) Crowns wedged in laterally, yet not overtopped. 



(i) Crowns compressed, partly overtopped. 

 dux* S. Suppressed trees, entirely overtopped. 



(a) Crowns still having vitality (shade enduring species). 



(6) Crowns dying or dead. 



The following illustration of the appearance of these tree classes will be found serviceable in 

 understanding these relations. 



3 4 5 6 7 8 9 10 11 12 15 14 15 16 17 18 13 20 



FIG. 26. Tree classes : Classification according to crowu development. Schematic. Class 1 (predominant) : Nos. 1,3, 0, 11, 16, 20; class 

 2 (codomiiiant) : Nos.8,13,18; class 3 (sundominant) : Nos.9,14,17; class 4 (oppressed) : Nos.5,7,12; class 5 (suppressed, a) : Nos.2,19; class 

 5 (suppressed, b) : Nos. 4, 10, 15. 



The degrees of thinning usually resorted to are the following : 



(1) Slight thinning takes out trees of class 5. 



(2) Moderate thinning takes out trees of class 5 and 4/>. 



(3) Severe thinning takes out trees of class 5, 4, and sometimes 3. 



The time when the first thinning should take place is generally determined by the possibility 

 of marketing the extracted material at a price which will cover at least the expense of the 

 operation. This is, however, not always possible, and the consideration of the increase in value 

 of the remaining growth, or rather of the detriment to the same by omission of timely thinning, 

 may then be conclusive. 



Ou good soil and on mild exposures interlucation may take place earliest, because here the 

 growth is rankest and a difference in the development of the different stems is soonest noticeable. 



