PRODUCTIVITY OF RECENTLY CUT LANDS 



227 



and locality. Stocking standards for seedlings 

 and for saplings represent much smaller percent- 

 ages of the better stocked stands found in nature. 

 Reasons for adopting these lower standards for 

 seedling and sapling trees will be found in the 

 subsequent discussion on Existing Stocking. 



In application of standards, field measurements 

 of each element on a recently cut area were calcu- 

 lated as a percentage or proportion of the appro- 

 priate standard. Such percentages were called 

 factors or ratings. A method of calculation was 

 adopted which integrated these factors into a 

 single productivity index. The possible range of 

 such indexes was to 100. The standards for 

 each locality were applied and productivity indexes 

 computed for every area examined in the locality. 

 Under this system, the standards might be low for 

 some ownerships where operating conditions were 

 more favorable than those prevailing in the 

 locality, or they might be high for ownerships 

 where operating conditions were more difficult. 

 No adjustment of standards was made for indi- 

 vidual ownerships. The assumption was made 

 that, for a given class of ownerships, the area 

 rated under standards too low for certain indi- 

 vidual ownerships were balanced by other areas 

 rated under standards too high for them. 



The standards together with instructions for 

 calculating factors and productivity indexes and 

 for field procedures were incorporated in manuals 

 for each region. These are summarized in the 

 appendix section Criteria. Each field examiner 

 was provided with a copy of the appropriate 

 regional manual and trained in its use. 



Because of limited facilities, the intensity of 

 survey coverage was aimed at reliable statistics 

 for each region only, but provision was made for 

 adequate statewide data where local interest sup- 

 plemented regional sampling to the extent neces- 

 sary. The method of choosing ownerships for 

 examination varied with size class. Sampling 

 methods were used for the extremely large number 

 of small private ownerships. For private owner- 

 ships of medium size, sampling was used in States 

 where this size class was numerous, but the recent 

 cutovers of all were examined in States with few 

 such ownerships. With a single exception, the 

 recently cut areas of all large private ownerships 

 were examined in each State. Generally, this type 

 of full coverage was also used for public lands. 

 The public lands and large private ownerships 

 were examined separately by working circles or 

 blocks. 



No area was examined that had been cut over 

 prior to January 1 , 1947. On an individual owner- 

 ship, the most recent cutting made between that 

 date and the time of examination was chosen for 

 field measurement. This procedure was followed 

 for the recently cut portions of each forest type on 

 the ownership. Thus a factor or rating for each 

 element and a combined productivity index was 



calculated for the recently cut portion of each 

 forest type on every ownership examined. On 

 many ownerships this procedure resulted in two 

 or more indexes depending upon the number of 

 types with recent cutting. In addition to this 

 productivity data, field examiners also recorded 

 for every ownership examined the area of each 

 forest type in which recent cutting had occurred, 

 the total commercial forest area, and other related 

 information required by the plans. 



Occasionally no recent cutting had taken place 

 on an entire ownership or on one or more forest 

 types of an ownership. These areas were con- 

 sidered as nonoperating. On each ownership with 

 recent cutting only the total area of forest types 

 in which cutting had occurred was classified as the 

 operating area of the ownerships. About 48 

 percent of all commercial forest land was classified 

 as operating area. 



Compilation of results was begun by dividing 

 the entire range of productivity indexes into 3 

 broad classes as follows: 



Equivalent pro- 



Productivity index range: ductivity class 



0-39 Lower 



40-69 Medium 



70-1 00 Upper 



The next step was to tabulate operating areas 

 by productivity classes in accordance with the 

 indexes previously calculated from field measure- 

 ment. Finally, the total operating area in each 

 productivity class was expressed as a percentage 

 of all operating area. Tabulations of the three 

 productivity classes are used to compare the rela- 

 tive condition of recently cut lands by ownership 

 classes, regions, forest type groups, and other 

 broad subdivisions of commercial forest land. 

 Additional similar tabulations were prepared to 

 show the relative effects of each element on the 

 proportion of area in the various productivity 

 classes. 



Earlier discussion of concepts pointed out that 

 standards for each element were based upon cur- 

 rent practical attainabilitj^. A productivity index 

 of 100 means that such standards were fully met 

 for all four elements. Any result showing that 

 50 percent of the recently cut lands in a given 

 region were found to be in the upper productivity 

 class means that 50 percent of such lands met 70 

 to 100 percent of the standards practically 

 attainable. 



The preceding summary of concepts and pro- 

 cedures is amplified on the pages immediately 

 following. Much of this amplification is neces- 

 sarily technical and quite detailed. If the reader 

 does not wish to go into further detail as to con- 

 cepts and procedures, he should pass over this 

 part of the report and turn to the discussion How 

 High Are the Standards, page 236, or to the results. 

 However, the fuller explanation will contribute 

 significantly to better understanding of the results 

 and is recommended. 



