These field classifications were those used in the original St. Regis study which developed a 

 procedure for collecting basic information for combined volume inventory and management 

 requirements. The definitions of these classes are those standardized by the National Forest 

 Survey, U.S. Forest Service. 



STRATIFICATION SCHEMES 



The 126 plots were then sorted by means of the previously recorded classifications into 

 each of 18 stratification schemes selected for testing. These schemes include most of the 

 traditional forest classes common to volume inventories plus a few peculiar to management 

 surveys. They included seven schemes based on field classification and measurements, eight 

 schemes based on photo interpretation and measurement, and three schemes based on classifi- 

 cations from a previously prepared type and stand- size map. The following brief description 

 includes the number of strata and the source of the measurements of interpretations used in 

 classifying. 



The first seven methods of stratifications are those based upon computed data from field 

 measurement of sample plots: 



1. Field stand size and density (10 strata). --Includes sawtimber, poles, seedling- 

 sapling, poor, medium, well stocked, and a catchall stand-size class of nonstocked . 



2. Field stand size (4 strata) .- -Same data as 1 - -collapsed into sawtimber , poles, 

 seedling- sapling, and nonstocked . 



3. Field density (3 strata) .- -Same data as l--collapsed into poor, medium, and 

 well stocked. 



4. Field species (10 strata) .- -Plots were stratified into white pine, ponderosa pine, 

 larch, Douglas-fir, grand fir, alpine fir, cedar-hemlock, spruce, lodgepole pine, and 

 nonstocked by plurality of cubic volume . 



5. Field site class (6 strata) . --Site index from site tree measurements taken on 

 sample plots was used to classify plots into six site classes. 



6. Field management category (5 strata) .- -Includes high risk, low risk, and imma- 

 ture sawtimber; pole and sapling stands not needing treatment, and such stands in need of 

 treatment. This is a management classification. Its efficiency in volume estimating is 

 easily tested, but its relative value in management surveys cannot be determined since 

 these same five categories were used in computing ranks . 



7. Field cubic-volume class (11 strata) .- -Includes 500 cubic-foot classes up to 4,000 

 cubic feet, and 1 , 000 -cubic -foot classes from 4,000 through 6,000 cubic feet. Relative 

 value for management surveys is easily determined, but volume efficiency cannot be 

 determined since computed plot volumes were used in stratification. 



The next eight methods of stratification are those patterned after the traditional field 

 classes but rely on strata identified on aerial photos by interpretation or measurement. 



1. Photo stand size and crown cover (9 strata) .- -Includes classes of sawtimber, poles, 

 seedling- saplings , poor, medium, and well stocked, as identified by measurements of total 

 height, crown diameter, crown cover, and tabular volume . 



2. Photo stand size (3 strata) . --Same data as 1- -collapsed in three stand sizes. 



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