44 METHODS OF TREATMENT [CH. 



formation of periodic blocks, are the same. There will be of 

 course no annual coupes laid out, but the possibility will be 

 extracted from every part of the block under regeneration in 

 which there are groups of young growth ready for extension. 

 The annual yield is determined by volume, and the regeneration 

 fellings will be progressively conducted all over the block during 

 the period by purely cultural considerations, by the removal 

 of the largest trees over advance growth, and by the subsequent 

 expansion of these groups by the progressive extraction of the 

 rest of the old stock. Preparatory and seed-fellings will often 

 not be required, as the fellings may follow the regeneration 

 instead of preceding it. All these points, however, are matters 

 of silviculture rather than of management, and in the working- 

 plan it will only be necessary to give effect to them in the rules 

 prescribing the nature and mode of executing the fellings. Some 

 provision may have to be made to facilitate the extraction of 

 the old crop without damage to the surrounding young growth. 



43. The Selection method. 



The high-forest of mixed ages, worked by the Selection method, 

 is, from the point of view of management, extremely simple. 



Here we have the forest in its natural irregular condition; 

 there is no artificial separation of age-classes, and there is no 

 division of the area into periodic blocks. The whole forest is 

 theoretically the same everywhere at any time, and any acre 

 in it is exactly like any other acre, and contains trees of all ages 

 from one year old up to the limit of the rotation. Since, however, 

 in practice it is not possible to work over the whole area, which 

 is often very extensive, every year, in order to pick out the trees 

 which have just attained exploitable dimensions, a felling-cycle 

 is adopted generally between five and thirty years and the 

 forest is divided into a corresponding number of sections, one 

 of which is worked over each year in succession. With a short 

 felling-cycle the crop retains all the characteristic features of the 

 irregular forest, while with a very long felling-cycle, it gradually 

 approaches the even-aged type. The considerations which should 

 determine the length of the felling-cycle are administrative and 

 silvicultural. The annual sections or coupes should be of manage- 



