86 CIRCULAR 3 3 3, U.S. DEPARTMENT OP AGRICULTURE 



102. Subordinate tables such as those in cords, those for trees above 4 inches 

 in diameter, and those for volumes below a 3-inch top, should be deduced from 

 the primary tables by converting factors instead of by direct preparation. 



103. The following information should be included in the final tables: 

 (cr) Species, common and scientific name. 



(6) Forest type. 



(o) Region. 



(d) Author and date. 



(e) Basic data — number of plots used and their distribution through the 



site and age classes. 



(f) Definition of site index used. 

 iff) Collectors of field data. 



(h) Average deviations of individual plots from the yield-table values 

 for factors mentioned in no. 98. 



104. All tables should contain information on the following factors: 

 (a) Average total height of dominants. 



(6) For entire stand, the 



(1) D.b.h. 



(2) Total height. 



(3) Number of trees per acre. 



(4) Basal area per acre. 



(5) Yield in cubic feet, entire stem, without bark. 



(6) Yield in board feet, International (^s-inch) log rale. 



In addition, tables giving similar information for the dominant stand, for 

 the stand above one or more diameter limits, and for yields in other units or to 

 other limits of merchantability should be included as needed. 



FOREST SERVICE POLICY REGARDING EXPERIMENTAL FORESTS, 

 NATURAL AREAS, AND PRIMITIVE AREAS 



The following regulation was approved by the Secretary of Agriculture on 

 August 7. 1930. as National Forest Regulation L-20 : 



The Forester shall determine, define, and permanently record a series of 

 areas of national-forest land to be known as experimental forests, sufficient in 

 number and extent adequately to provide for the experimental work necessary 

 as a basis for forest production or forest and range production in each forest 

 region, these areas to be dedicated to and used for research ; also where neces- 

 sary a supplemental series of areas for range investigations to be known as 

 experimental ranges: and a series to be known as natural areas sufficient in 

 number and extent adequately to illustrate or typify virgin conditions of forest 

 or range growth in each forest or range region, to be retained in a virgin 

 or unmodified condition for purposes of science, research, and education ; 

 and a series of areas to be known as primitive areas and within which will 

 be maintained primitive conditions of environment, transportation, habitation, 

 and subsistence, with a view to conserving the value of such areas for purposes 

 of public education and recreation. Within any areas so designated, except 

 for permanent improvements needed in experimental forests and ranges, no 

 occupancy under special-use permit shall be allowed, or the construction 

 of permanent improvements by any public agency be permitted, except as 

 authorized by the Forester or the Secretary. 



These instructions relating to experimental forests, natural areas, and 

 primitive areas were approved by the Secretary. 



EXPERIMENTAL FORESTS 



The purpose of experimental forests is to make permanently available for 

 silvicultural. range, products, and other related forest research carefully 

 selected areas as fully representative as possible of conditions in important 

 parts of forest regions and large enough to meet present and foreseeable future 

 needs. In essence these areas are field laboratories for intensive investigative 

 work. In the interest of results of the greatest breadth and reliability, of 

 protection, of efficiency, and of the best working conditions for the investigative 

 staff, the work of forest experiment stations will be concentrated as fully as 

 possible on them. 



