Method for Regulating Yield. 23 



rough regulation, the latter marking recent progress. All these 

 are necessarily general, applying as they do to varied conditions 

 over a large area, and much is left to the intelligence of the local 

 administrating officer for the successful application of them. 



Cultural rules alone are all that are necessary for treating very 

 irregular stands where a superabundance of over-mature trees 

 form the bulk of the felling, and for those partially ruined by 

 misuse or fire. Elsewhere, in addition to cultural rules, guides 

 for regulation are demanded. Especially is this true in the 

 management of the selection forest. 



Before developing principles for the regulation of the selection 

 forest, a few words as to what constitutes a normal selection 

 forest will not be out of place. In the normal selection forest 

 the trees of all ages are apparently intermingled with no degree 

 of order, but, ideally, on each area the total area occupied by any 

 age class will equal the total area occupied by any other age class'. 

 It follows, then, that the number of individual trees on such an 

 area will progressively vary from very many of a young age 

 class to relatively few of an old age class ; but the areas occupied 

 by each class will be equal. 



If to this normal age class gradation we add the condition that 

 each tree at all times must be correctly spaced so that it is neither 

 unfavorably retarded by crowding nor yet given so much space 

 that it develops into a limby, knotty tree of impaired commercial 

 value, we shall attain both normal growing stock and normal in- 

 crement and hence a normal forest. Such a stand might well 

 serve as the ideal to strive for, or, rather, toward ; for the com- 

 plete attainment of it can scarcely be expected. Each timber 

 sale, however, offers the opportunity to make some headway 

 toward the desired goal. 



Our forests are abnormal, except possibly by accident on small 

 areas, in one, two, or all three of the above conditions. Before 

 remedial measures can be wisely taken, obviously, it is necessary 

 to analyze the stand in order to ascertain in what respect and to 

 what extent it is abnormal. General rules for regiilation, unlike 

 cultural rules, are of slight value, because each stand diflfers so 

 widely. Hence, principles for deriving specific rules applicable 

 to the stand in question should be understood, in order that each 

 may formulate his own rules to fit the case. With normal yield 



