38 METHODS OF TREATMENT [CH. 



forester in charge of the forest will have sufficient professional 

 knowledge to carry out all ordinary operations in a fit and 

 proper manner. 



37. Methods included in even-aged high-forest. 



Under the head of even-aged high-forest, there are a small 

 number of variations of the method of treatment which will have 

 to be considered separately. These are : 



(1) The uniform method. 



(2) The group method. 



(3) Clear-felling with natural regeneration. 



(4) Clear-felling with artificial regeneration. 



(5) Strip-felling. 



38. The Uniform method. 



The uniform method of successive regeneration fellings, called 

 in France the method of natural regeneration and thinnings, 

 and in Germany the shelter-wood compartment system, is the 

 typical method of even-aged high-forest management, and the 

 group and strip methods are merely variations of it. 



In this method the working-circle is divided into a few 

 (generally about four to six) blocks of approximately equal 

 area, each containing an equal range of age-classes. The number 

 of blocks to be so formed is found by dividing the rotation by 

 the number of years considered necessary under existing con- 

 ditions to complete the regeneration of a block by successive 

 regeneration fellings. 



Thus, if it was estimated that about thirty-six years would be 

 required to regenerate completely a block of mature crops under 

 conditions where natural regeneration was rather difficult and 

 slow, and the whole rotation was 144 years, there would have 

 to be four blocks, and Block I would contain the crops forming 

 the oldest quarter of the growing stock; or if the rotation were 

 TOO years, and a period of twenty years was considered sufficient 

 in which to regenerate a block, there would be five blocks. In 

 this way the area is divided up into blocks corresponding to the 

 same number of periods into which the rotation is sub-divided. 



These blocks are therefore called periodic blocks, because each 

 block is to be regenerated in the corresponding period, and the 



