THE WORKING SECTION. ^79 



consists of only one series of age classes, it is identical with a 

 working section. In working circles of some extent, however, 

 different conditions may demand the establishment of two or 

 more series of age classes, or a division of the working circle 

 into two or more working sections. The principal causes, 

 which demand the formation of working sections, are the 

 following : — 



a. Spenps. 



When several species appear in a working circle as pure 

 woods, they must be placed into different working sections, 

 if they require essentially different treatment, or if a certain 

 quantity of material of each species has to be cut annually. 

 When, on the other hand, the several species appear in mixed 

 woods, such a separation is neither practicable nor necessary. 



h. Sijlvicultural System. 



Each sylvicultural system may demand the formation of a 

 separate working section. If, for instance, part of a high 

 forest is treated under the compartment system, and another 

 part as a selection forest, each part must be formed into a 

 separate working section. Coppice woods and coppice with 

 standards always must form separate working sections. 



c. Rotation. 



Even in the case of the same species and sylvicultural 

 system, areas worked under different rotations must be placed 

 into different working sections, whenever an even or approxi- 

 mately even annual yield is expected. Unless this is done, 

 it will happen, either that the annual yield is uneven, or, if 

 the same quantity is cut every year, that the different 

 rotations merge into one. 



d. Servitudes. 



If part of a working circle is subject to servitudes, it should 

 be placed into a separate working section; this is necessary to 



