28 DEFINITIONS. 



of the area Is worked annually, forms only a single Working Circle, if 

 it is divided into twenty-five annual coupes; *but it may be split up 

 into two separate groups of twenty-five annual coupes each, in which 

 case it would comprise two Working Circles. Further on we shall 

 explain how to operate in order to form Working Circles. 



The quantity of produce that can be extracted year after year 

 from any Working Circle or forest throughout a whole Rotation or 

 part of a Rotation, represents the ANNUAL yield, or simply 

 YIELD of that Working Circle or forest. It is usually expressed in 

 cubical contents or by an area ; thus we say that such and such a 

 Working Circle of high forest returns a yield of 16,000 cubic feet (of 

 wood and timber understood) or that in such and such a Working 

 Circle of copse the yield is 15 acres 3 roods, 17 poles, meaning that 

 the stock on that area is exploited every year. 



In high forests worked according to the Na tural Methoji the 

 Rotation is usually long and even very long. It generally ranges 

 from 150 to 200 years for the oak, and from 120 to ISO years for 

 the beech, Scots' pine and the silver and spruce firs. Now as It is 

 impossible to order at once in advance, for the whole duration of 

 such long terms, the succession and nature of the exploitations to be 

 made in any given forest, it is an invariable rule In organising 

 high forests to divide the Rotation into a certain number of equal por- 

 tions, which we will term Periods. In connection with this division 

 of the Rotation, the area itself of the Working Circle is split up into 

 an equal number of portions, each of which is worked in succession 

 during the corresponding period of the rotation. These divisions 

 of the Working Circle we will call Periodic Blocks. This two-fold 

 division being effected, according to rules to be laid down in a future 

 chapter, the next thing to do is to prescribe, for the term of one 

 Period only, the nature, order and extent of the exploitations to be 

 carried out simultaneously in each of these Periodic Blocks. 



It thus follows that the quantity of wood and timber to b« felled 

 each year is obtained from exploitations differing from one another 

 In character, but which naturally fall into two well-defined 

 categories : — 



• Coupe— area iu which a cutting is made. (Translator.) 



