8 BULLETIN 275, U. S. DEPARTMENT OF AGRICULTURE. 



capable of producing large saw timber, can not be justified. * * * 

 It would probably be better to fix the rotation at the period during 

 which the rate of volume production is greatest or shortly after it, 

 provided this is long enough to give the most valuable product." 



Munger 1 comes somewhat closer to a consideration of the financial 

 factors for a rotation of Douglas fir in pure even-aged stands in the 

 Pacific Northwest. 



From the quotations given, one fact stands out clearly: We are still 

 groping more or less in the dark where choice of rotation is con- 

 cerned, and we are even lacking the fundamentals upon which to 

 base the principles to govern us in making a proper choice. It also 

 appears that in many cases the term "actual felling age" should be 

 substituted for rotation. Rotation in itself signifies return or succes- 

 sion in a series. Fernow 2 has warned, as early as 1905, against mix- 

 ing up ' • actual felling age, the time when a stand is actually cut or to 

 be cut, and normal felling age (rotation), the time when in a scheme 

 of continued management it is proposed to have it cut again and 

 again — a mere standard time. Few stands are cut in the age of the 

 rotation determined for the forest as a whole." Where a "rotation" 

 of yellow pine, for instance, of 200 years is advocated, it is evident 

 that this can not be meant to constitute the fixed period at which 

 yellow pine should be cut again and again in the future. It is really 

 the actual felling age, the time when a given stand of yellow pine is 

 actually to be cut in the future, not a succession of 200-year periods. 

 The rotation itself will be much shorter, as European experience has 

 shown us. Moreover, it is more than doubtful whether our successors 

 in 200 to 400 years will pay much attention to the rules we may try to 

 lay down for so remote a future. 



CUTTING CYCLE. 



The impossibility of predicting with even a modest degree of proba- 

 bility what will happen in the future and of anticipating changes in 

 conditions of an economic nature is responsible for the vagueness with 

 which the question of fixing definite cutting cycles is treated. Tenta- 

 tively, cutting cycles of about 50 years have repeatedly been advo- 

 cated for uneven-aged stands (mixed and pure) under the selection 

 method, as a policy to be followed on virgin national forests. If 

 present economic conditions should prevail in the next 50 years — that 

 is, if the demand for timber should continue to fall far short of the 

 actual annual increment — it would hardly pay a lumbering concern 

 of the future to extend its operations to cut-over areas before 50 to 

 60 years had elapsed. Even then it seems doubtful whether the 



1 Munger, T. T. The growth and management of Douglas fir in the Pacific northwest. U. S. Dept. Agr., 

 Forest Serv. Circ. 175, 27 pp., 4 figs., 1911. 

 2 Femow, B. E. Forest terminology. In Forestry Quart., v. 3, no. 3, pp. 255-268, 1905. (See p. 264.) 



