572 Forestry Quarterly. 



(3) The legitimate period of rotation which appears to be 

 indicated from the above considerations, may be said to be in 

 the neighborhood of 100 years. That would allow the felling of 

 112,500 acres a year, carrying a yield per acre of 40,000 b. f., or 

 4-| bilHon b. f. altogether. The actual period of rotation may 

 prove in the end to be either greater or less than 100 years. If 

 it should prove to be 120 years, the area available yearly would be 

 94,000 acres with a production of 4,747,000,000 feet ; and if, on 

 the other hand, the visible supply should be depleted in 80 years, 

 the acreage available each year would rise to 140,000, yielding 

 4,200,000,000 feet. 



Although there would not be so great a difference in the total 

 annual yields for the two periods, as might be expected, owing 

 to the compensating effect of the change in area available, it may 

 be said that the longer rotation period would be the more ad- 

 vantageous, not only on account of the greater proportional pro- 

 duction and higher stumpage value, and therefore increased reve- 

 nue, but also because at 120 years there would be a greater per- 

 centage of clear lumber and a finer quality. 



Again, it is hardly an exaggeration to say that the strictest 

 economy in logging might conceivably lengthen the rotation period 

 by at least ten years. The average yearly output for 100 years 

 would be two billion feet. The waste is represented by 10% 

 which is left in the woods, or 200 million feet a year, which for 

 100 years would be 20 billion feet, representing ten years supply. 



The value of the crop in any particular decade must be based 

 upon an assumption of the probable rate of increase in stumpage- 

 values. Authorities differ widely on this question : some going 

 as high as 25c a year. The assumption has been published by 

 authority of the U. S. Forest Service that the value will have 

 increased to $5.00 a thousand in 40 years time, and that there- 

 after the price will increase 50c every ten years. At this very 

 conservative estimate we find that the gross value of our stump- 

 age would be, at 80 years $213 an acre; at 100 years, $320; at 

 120 years, $454; or a gross revenue from the areas available for 

 cutting of those years of 29 million, 36 million and 42 million 

 dolars respectively. 



Many difficulties will have to be overcome before a sound 

 scheme of rotation-cutting can be established. For instance, 

 112,500 acres represents an area probably three times greater than 



