8 



of several compartments which, under the timber-sale policy, are 

 set aside as a reserve from which to supply an established sawmill 

 plant after the completion of the current sale. 



In very extensive plans based upon meager data and lacking a good 

 topographic survey, all immediate needs may sometimes be satisfied 

 by dividing the entire working circle into blocks without further 

 division into compartments or smaller units. 



The block is a division of convenience. It is not necessarily perma- 

 nent and there need be no hard and fast rules to govern its use. 

 For the sake of simplicity its use should be restricted to situations 

 where a real need is to be served. 



THE COMPARTMENT 



The compartment is the forester's working unit of area. He 

 plans and executes his operation by compartments or subdivisions 

 thereof; he describes the forest stands, keeps an inventory, and 

 records action taken, by compartments. The compartment is a 

 permanent territorial division and its boundaries should be located 

 with care and a full realization of the very practical purpose which 

 it is to serve. 



iN'eedless to say, compartment boundaries should be plainly and 

 permanently marked on the ground and clearly shown on all maps. 

 The areas should be so designated that they may be readily identified 

 on the ground and on the map. Wherever available, natural topo- 

 graphic features such as ridges, streams, cliffs, lake shores, etc., 

 should be used to mark compartment boundaries. These may be 

 supplemented by roads, trails, and property lines. A cove, a gulch, 

 a hollow, or the watershed of a small stream makes a very logical, 

 easily identified compartment. 



In a level country or in a region where marked topographic fea- 

 tures are lacking the rectangular system of the public land survey 

 gives a very convenient basis for division into compartmentSc The 

 section of 640 acres makes a compartment of convenient size and one 

 that is easily found and identified on both the ground and the map. 



Compartments need not be logging chances or sale areas, nor 

 need they be uniform in the type, age-class, or condition of the 

 stand. All such features are taken care of in the subcompartments. 



A compartment may vary m size from less than a hundred acres 

 to several thousand acres, depending upon the degree of refinement 

 used in silvicultural treatment, and upo^ the size of the natural 

 toj^ographic units that characterize the terrain. If the compart- 

 ments are too large, it becomes difficult to describe the forest land 

 adequately, to allocate the various operations, and to record their 

 history. If the areas are too small, there is introduced a needless 

 and hampering complexity in management. 



SUBCOMPARTMENTS 



If the intensity of the management or the diversity of forest con- 

 ditions call for it, the compartment may require division into smaller 

 units. Subcompartments may be topographic divisions but are usu- 

 ally based upon the type, age class, or physical condition, or the 

 prescribed treatment of the timber stands. For instance, a smaller 



