460 Forestry Quarterly. 



All data available confirm this conclusion, that the total volume 

 production cannot be increased beyond a certain amount attain- 

 able under proper crown density. From the standpoint of vol- 

 ume production a rational practice of the old method of thinning 

 seems to be unassailable. 



The second requirement, namely of value production, however 

 changes the aspect. 



After referring to what constitutes value and to the observa- 

 tion that diameter and price more or less parallel each other up 

 to certain limits (see p. 340 of this volume), the author points 

 out that of two stands of the same species, same soil, same age and 

 density, the one with the smaller number of stems has the larger 

 diameters (although usually smaller volume) : where a smaller 

 number participates in the crown cover, the individuals have larger 

 diameters, in other words, the diameter is a function of the light 

 enjoying crown. 



Since, apparently at least, a given site presents a limited growth 

 energy, if a larger number of individuals must grow on it, each 

 individual secures less than if there were fewer. Hence, the 

 number of stems per acre, stock density, is of importance, and the 

 regulation of numbers, which does not enter into the considera- 

 tion of the old thinning practice, becomes a second primary con- 

 cern. Examples are given which accentuate the failure of the 

 old method in this respect. 



The third primary requirement which influences value produc- 

 tion is to secure best stem forms ; not only forms of bole, but of 

 the crown as well, which is in relation to form development. 



Finally the author formulates the object of stand improvement; 

 to utilize to the fullest the source of energy on a given site for the 

 existing stand and to distribute its results over stems determined 

 as to kind and number. 



This direction is given by opening up around selected individ- 

 uals in order to increase the lighted part of the crowns. The 

 apportionment of the existing growth energy among the individ- 

 uals would appear the most important and most productive task 

 of the forester, and this is attained by thinning in the dominant, 

 which will furnish larger intermediate and smaller final harvest 

 yields, the opposite of thinnings in the subordinate stand. 



General recipes of procedure to attain these objects cannot be 

 given. General considerations are, that in order to preserve soil 



