38 THE THEORY AND PRACTICE OF WORKING PLANS 



could be constructed without any systematic division of the 

 area. The need for these divisions grows with the refinements 

 in management, and while it would be mere play in most Amer- 

 ican forests to mark each compartment and subcompartment 

 in the map or on the ground, a skeleton outline of the salient 

 divisions will often serve to facilitate and to systematize the 

 working of a forest. Unnecessary divisions must be avoided. 



For these divisions topographic features, roads, trails, etc., 

 should be made the boundaries; even in flat country the hewing 

 through of compartment Unes is justified only under most 

 intensive conditions. 



The customary subdivisions of a forest are: 



The working unit (syn. working plan unit. Ger. Wirt- 

 schaftsganzes). 



The working group (syn. management class, working block, 

 working circle, working section, Ger, Betriebsklasse). 



The block. 



The compartment. 



The lot or subcompartment. 



These may be defined as follows: 



Working Unit.^The forest area managed under an indi- 

 vidual working plan and by means of the plan of regulation of 

 the cut, usually with the idea of a sustained yield. It may or 

 may not coincide with an administrative unit. 



Working Group. — A unit of forest organization, comprising 

 an aggregate of compartments or stands to be managed under 

 the same silvicultural method and rotation. 



Block. — A major division of the working unit, being a per- 

 manent land subdivision in the forest, intermediate in size 

 between the working unit and a compartment. A block is 

 usually based on topography, such as the whole or portion of a 

 drainage, containing from looo to 100,000 acres. 



Since the division of a block is usually topographic, a suit- 

 able local name can generally be taken from some salient topo- 

 graphic or cultural feature contained therein. 



Compartment. — A unit of forest organization for purposes 



