ROTATIONS AND CUTTING CYCLES 227 



trees furnish the kind of produce naost wanted." Endres says "^ that 

 "by rotation period or rotation is meant that time which elapses under 

 normal conditions between the planting and the utilization of a stand. 

 In the case of the working group the rotation is the average time of grow- 

 ing merchantable material which is the fundamental consideration in 

 working plan calculations." Variations from the normal may be due 

 to unusual silvicultural, financial, or economic conditions. Rotation 

 is not to be confused with cutting-cycles ^' in selection forests, which 

 is the period elapsing between cuts on the same area. Obviously in 

 selection forests the length of the cutting cycle has an important in- 

 fluence on the amount removed, and the frequency of cut also has a 



" Endres, pp. 220-221. 



2^ There are strong arguments in favor of a long cutting period. The longer the 

 time between cuts the more time will be allowed for eradicating damage caused by log- 

 ging. When it is necessary to cut a amall amount per acre over a large area it neces- 

 sarily increases the cost of logging. Some argue that the cutting cycle should not be 

 less than the time which it will take the tree to pass from one diameter class to the follow- 

 ing. On the other hand well-known writers, like M. Gazin, argue that the cutting cycle 

 should be very short — 5 or 6 years — in order to secure the yield without opening up 

 the stand too much and without the necessity for heavy cuttings. If, for example, the 

 growth per cent is 4, a cutting cycle of 5 years means removing an amount equal to 20 

 per cent of the original volume; with a 10-year cutting cycle 40 per cent miist be re- 

 moved; and with 15 years, 60 per cent, which is certainly too much from a cultural 

 point of view. A short cutting cycle, moreover, enables the removal of dead and 

 dying trees which otherwise would lose a great deal in value. As a general rule, the 

 more intensive the treatment the shorter the cutting cycle. With the recognized 

 tendency to coniferous forests, intensive treatment becomes more and more necessary 

 if the spruce, fir, or pine is to be favored in the cutting. Moreover, recent yield in- 

 vestigations show that the growth of coniferous stands is much more than had been 

 supposed. Schaeffer, a specialist in fir forests, advocates neither the very short nor 

 the very long cutting cycle, but has called attention to the possibility of cutting over 

 the same ground twice during one cycle. This double cut idea is only advocated, how- 

 ever, for the rich compartments, since one cut per cycle would be sufficient for the 

 areas where conditions of growth are less favorable. He says: "The cutting cycle of 

 16 years, usually followed under average conditions in the Savoie Alps, can be con- 

 tinued with 8 years between the cut. In calculating the yield with conservatism it 

 will result in certain compartments realizing every 16 years 30 per cent or more of the 

 stand. This volume cannot be secured at one time without endangering the future of 

 the stand." Two cuts, therefore, would be justified during the course of the formal 

 felhng cycle. However, it should be recognized that in exceptionally rich forests it 

 would be possible to reduce the cutting cycle to 12 years and the interval between the 

 two cuts to 6 years. On the other hand, in certain stands where the time necessary for 

 trees to pass from one diameter class to another is 40 years, 20 years woxild be a 

 better felling cycle, but instead of fixing the length of the cutting cycle arbitrarily 

 Schaeffer advocates the determination of the number of years which it takes a tree to 

 pass from one diameter class to another, and adopts this figure, provided during this 

 cutting cycle each compartment will be cut over twice, but after the first cutting no 

 new stocktaking need be made. (De la Dur6e de la Rotation dans les Futaies Jar- 

 dinfe. A. Schaeffer, 1907. B. de S. F. de F. — C. et B.) 



