SELECTION SYSTEM 177 



same area more than about once in every 15 years; though 

 these periodic cuttings vary from 10 to 20 years. 



Where a large area is being dealt with, it will be 

 advisable to divide it up into a number of equally productive 

 areas, corresponding in number with the number of years 

 that elapse between the fellings which take place over 

 any single area. Thus an equal yearly income may be 

 looked for and the management of the area will be more 

 methodical. 



Whenever grass and weeds appear on vacant spots, it 

 should either be removed, and the ground broken up so as 

 to form a seed-bed, or else artificial aid should be given by 

 way of planting. 



Rabbits must always be exterminated from the woods. 



The number of trees, which will vary more or less in age 

 classes, since fellings and thinnings take place periodically 

 (and consequently the regeneration will also be more or 

 less periodical), will be determined by the length of the 

 rotation. 



The canopy should be about as dense as that found in 

 even-aged high forest, except that the relative density of 

 the older trees should be somewhat less, so that the younger 

 trees may have rather more light and growing space. If 

 this relative density is required, it may be ascertained 

 by comparing the number of trees in any age class with 

 the number of like age that would be occupying a 

 similar area under close-canopied high forest, supposing 

 always that the trees of the particular age class under the 

 selection system are all growing together on a confined 

 area. 



In order to make this comparison per acre, it is necessary 

 to multiply the number of trees per acre in an age class 

 under the selection system, by the number of age classes ; 

 and that will show the number of trees which an acre fully 

 stocked with that age class will be supporting. 



Thus, supposing that Beech are grown under the selection 

 system, and that the oldest trees are cut when 105 years, and 

 that cuttings are made every 1 5 years, and that the following 



M 



