ORGANISATION OP SELECTION-WORKBD FORESTS. 189 



sum of production and of the available material on the ground. That 

 quantity should be fixed only for a limited period, and will be; 

 ,large or small according as the forest is well or poorly stoclsed with 

 old trees. The annual yield would vary only once after a fair- 

 ly long interval, to be sustained again for another interval of more 

 or less equal duration. As to the march of the exploitations, there 

 is no reason[here for limiting them to fixed areas ; for it would be a 

 matter greatly to be deplored if poorly stocked compartments were 

 overworked and well-stocked compartments worked under their 

 full capacity. The Amenagiste can therefore only give the order in 

 which the compartments should be severally taken up and state 

 whether the periodicity should be long or short. 



It is necessary to revise frequently the annual yield of forests 

 worked by Selection, when it has been fixed according to cubical 

 contents and not to number of trees to be felled. Such revisions 

 constitute the entire provision against the evil results that may arise 

 out of the necessarily complete uncertainty regarding the annual 

 sum of production. The present condition of the forest compared 

 compartment by compartment with what it was at the beginning of 

 the Period, as described in the Organisation Project, and the volume 

 of the formed trees it now contains as compared with the volume 

 of the trees that have been exploited, will furnish data of the 

 highest necessity for the redetermination of the yield. 



