26o Forestry Qttarterly. 



Only the greater amount of foliage of the more tolerant trees 

 offsets their lesser assimilation energy, the general rule being 

 that foliage amount is in inverse ratio to energy of assimilation. 



From a managerial standpoint light is all potent. The problem 

 is to increase the yield or shorten the rotation for the same 

 yield, or both. The solution is to make a greater use of light 

 influence in the care and regeneration of stands. 



With suitable form, value increases with volume, i. e. diameter, 

 almost ad infinitum for such species as oak, ash, beech, larch, 

 pine, etc., but only up to a certain diameter for others as spruce, 

 etc. In general then, our aim should be to attain satisfactory 

 volume production. For this, only the vigorous promising better 

 shaft- formed trees should be favored by increased growing space. 

 This idea of favoring selected trees by earlier or later lighting is 

 already old, but in spite of its excellent results its advocates have 

 made no noteworthy school. If to-day we take a middle position 

 between open stand and closed stand management, we have to 

 thank chiefly the knowledge given us by forest experiment sta- 

 tions. A practical knowledge of the light question is possible 

 only through sufficiently long, systematic and result-compared ex- 

 periments in regard to the different methods of handling stands. 

 The publication of the results of such experiments, especially 

 those of Schwappach and others in Prussia has advanced very 

 much the valuation of light influence- The highest value pro- 

 duction is not in close crowned, densely stocked stands and long 

 rotations, but in stands of fewer and more vigorous stems with 

 crowns .3 to .4 of total height, which will form equal annual 

 rings to a greater age. Max Wagner says each light beam idle 

 because not rightly guided means a loss of power. We may go 

 farther and say that the light should be devoted only to trees 

 producing usewood. Of course, too severe thinnings which fa- 

 vor the humus exhausting soil flora must be avoided; but the 

 procedure of allowing loss of power by keeping full crown 

 cover during the entire life of the stand, is very unsatisfactory. 

 And even if the volume production is uninjured, e. g. for spruce 

 and pine, the value production suffers. Growing stands in open 

 position cannot, to be sure, produce more total increment, but 

 putting it on fewer stems means quicker diameter and value 

 increase and therefore greater profits. For oak and beech, the 

 most important broad-leaved species, the sam.e holds in even 



