COPPICE WITH STANDARDS. 223 



The area occupied by each overwood class can only be 

 determined by assuming that each gradation occupies an equal 

 area of ground ; hence the youngest gradation will have most 

 trees, and the oldest least. Imagining now that the age classes 

 of the overwood were not intermixed, but that the trees of each 

 class were brought together on separate areas, then the over- 

 wood, apart from the coppice, would form an open high forest 

 resembling a selection forest. The areas to be allotted to the 

 several classes may, therefore, be considered as equal. The 

 youngest would contain the standards from 1 to r years, the 

 next those from r + 1 to 2 r years, and so on. By degrees, 

 the youngest class passes through all the intermediate stages, 

 until it becomes the oldest and is cut over in the course of r 

 years. At each annual cutting, therefore, an equal area must 

 be cut over, on which the new, that is the youngest, gradation 

 is started, either naturally or artificially. 



j[ 



The annual coupe is c = and ^4 = c x r. 



T) 



The number of overwood classes is = = t , hence 



r 



A A c, 



Area of each age class on each annual coupe = = = . 



R txr t 



As the whole forest consists of r coupes, each overwood 

 class, consisting of r gradations, contains, in a normal forest, 



c A 



- X r = units of area. This shows that, theoretically, 



v L> 



the proportion of the age classes is the same as in high forest, 

 although the distribution is different. 



Example. Data as before : 



A = 200; R = 100; r = 20, number of overwood classes 



* = 5. 



A 200 

 Normal annual cutting area c = = 10 acres. 



On each coupe each age gradation ) c 10 

 of overwood occupies . . j 1 ~ 5 



