8 MISC. PUBLICATION 11, U. S. DEPT. OF AGRICULTURE 



of several compartments wh ch, under the timber-sale policy, are 

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

 plant after the completion of the current sale. 



In very extensive plans l)ased upon mea<?er data and lacking; a orood 

 topojrraphic survey, all immediate needs may sometimes be satisfied 

 by (iividinir the entire workin*^ circle into blocks without further 

 dnvsion 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 «j:overn 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. 



Needless to say, compartment boundaries should be plainly and 

 permanently marked on the jj^round and clearly shown on all maps. 

 The areas should be so des:<2;nated 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 gulrh, 

 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 compartments. 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 t3'pe. age-class, or condition of the 

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



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

 to several thousand acres, depending upon the degree of refinement 

 used in silvicultural treatment, and upon the size of the natural 

 topographic units that characterize the terrain. If the compart- 

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

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

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

 and hampering comi)lexity in managoinent. 



SUBCOMPARTMENTS 



If the intensity of the manag(>ment or the diversity of forest con- 

 ditions call for it. the comjjartment may require division into smaller 

 units. Subcomi)artments may be topographic divisions but are usu- 

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

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



