FOREST SURVEY METHOD 



A. The forest resource statistics in this report are based on a field 

 survey made during 1947. Briefly the method used in making this 

 survey was as follows: 



1. The forest area was determined by an area sampling system 

 which involved measuring and classifying systematically 

 distributed sample segments. 



2. The timber volume was determined by measuring the trees 

 found on randomly selected one-fifth acre plots located 

 within the sample segments. 



B. The basic data from which the area and volume were determined con- 

 sisted of the following field samples: 



: Area 



Volume 



Class : Number of: 

 : sample : 

 : segments : 



Area per : 

 sample segment* 

 (acres) 



: : Area per 

 Number of: sample plot 

 plots : (acres) 



I 37 



2,560 



111 1/5 



II & III 96 



640 



192 1/5 



C. Distribution of the area sample segments and volume plots was con- 

 trolled by the following method: 



1. The entire area was divided on 1-inch-to-the-mile base maps 

 into three primary classes: 



Class I Areas predominantly forest for which aerial 



photographs were available. 

 Class II Areas predominantly nonforest for which 



aerial photographs were available at moderate 



cost. 



Class III Areas predominantly nonforest for which 

 aerial photographs cost more than $2 per 

 print, or for which there were no aerial 

 photographs . 



2. Each of the three primary classes were further subdivided in- 

 to units in the following manner: Beginning with a random 

 selection, Land Office section corners were marked on a base 

 map at 4-mile intervals for areas in Class I, 7-mile intervals 



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