60 



THE THEORY AND PRACTICE OF WORKING PLANS 



maximum average volume production, or the maximum average 

 value production. 



The higher the average yearly production of a piece of 

 woodland, the greater, of course, will be its continuous produc- 

 ing value if cut over repeatedly. For example, in the second- 

 growth hardwoods in Connecticut * the average annual growth 

 in cubic feet and cords culminates as follows: 



Chestnut type: best sites and medium sites 35 years 



Chestnut type: poorest sites 40 



Oak-chestnut type: best sites and medium sites 30 " 



Oak-chestnut type: poorest sites 35 " 



Oak type: best sites and medium sites 35 " 



Oak type: poorest sites 40 



These lengths of rotation are so nearly similar that it is safe 

 to place the cordwood rotation for second-gi'owth hardwood 

 stands at from thirty to forty years. To illustrate how silvi- 

 culture enters in as a limiting factor, the rotation for stands con- 

 taining much red, black, or scarlet oak should be thirty or 

 even twenty-five years in order to secure successful sprout 

 reproduction of these species. 



Another example of the economic rotation may be taken 

 from Douglas fir on the Pacific Coast. According to published 

 tables t the economic rotation for cubic volumes and board- 

 foot volumes for best, medium and poor sites, in western 

 Washington and Oregon is as follows: 



* Bui. 96, Forest Service, U. S. Dept. of Agri. Tables 30, 32, and S3' 

 t For. Quart., Vol. XII, p. 447, table 6. 



