102 



in fixed areas were prescribed in advance the material cut 

 could not be solS. It has been sometinaes sought to get 

 over this difficulty by prescribing the areas to be talieii in 

 hand each year, leaving the executive officers to make the 

 felling heavy or light according to the demand at the time. 

 This, however expedient it may be from a revenue point of 

 view, is nevertheless sylviculturally a faulty system. Theo- 

 retically the state of the crop determines the nature of the 

 felling. The object of restoration fellings during a provi- 

 sional rotation is to assist in bringing the crop to its normal 

 condition. To regulate the intensity of the fellings by the 

 demand might have just the contrary effect, and might 

 defeat the chief object which the plan should have in view. 

 In practice, however, it would often be mischievous to fell 

 trees which might be profitably disposed of hereafter. The 

 conditions of each case must be weighed ; and it may some- 

 times be advisable to confine the restoration or improve- 

 ment fellings to the trees least capable of improvement, 

 . leaving other stems, which in strictness ought to be removed,, 

 for possible sale in the future. 



The transformation fellings should be prescribed by area^ 

 in the manner already explained for fellings regulated by 

 the cultural method. 



Section IX. — The working scqemb and the calcula- 

 tion OP THE POSSIBILITY TIN DEB THE METHOD OF 

 SUCCESSIVE REGENERATION FELLINGS. 



1. General worhing scheme.— The essential cultural feature 

 of this method consists in the gradual removal, by successive 

 fellings over definite and limited areas, of the crop to be 

 regenerated. While this regeneration by successive fellings 

 is proceeding, the crops whioh have been or have still to be 

 regenerated are subjected to cleanings and thinnings. The 

 principal or regeneration fellings are prescribed usually by 

 volume, though in special cases, where an absolutely equal 

 volume return is not desired, the possibility may be expressed 

 by number of trees. In the forner case, the pcssibility in 

 cubic feet having been ascertained, as many trees as are 

 found to jield this Tolume are removed wherever, in view of 

 the state of the crop, this is required for sylvicultural 

 reasons. 



a. The possibility.-(ffl) Volumetric me^Aod— Formerly the 

 volume of material to be removed annually was determined 



