Stocking was determined by the stocked-quad- 

 rat method, which consisted of examining four 

 contiguous squares at regular intervals along a 

 compass line. For trees less than 3.1 inches 

 d. b. h. a 13.2-foot square was used and for trees 

 3.1 to 11.1 inches d. b. h. a 20.9-foot square was 

 used. The 13.2-foot square was considered stocked 

 if it contained one well-established seedling and 

 the 20.9-foot square if it contained one tree of pole 

 size. Clear-cut areas and burns were also exam- 

 ined by the stocked-quadrat method to determine 

 if they were restocking. 



Before considering a township type vellum com- 

 pleted, the mapper carefully matched the type 

 boundaries along the four sides with the vellums 

 of adjoining townships. 



Determination of the site quality of the forest 

 land and the preparation of township site maps 

 were carried on in the field concurrently with the 

 type mapping and check cruising. Although 

 height at any given age is the precise measuring 

 stick of site, it was necessary to use methods that 

 did not involve a large number of age and height 

 determinations. In general, the procedure fol- 

 lowed in the field was for the type mapper to make 

 frequent age and height determinations in a large 

 number of stands until he was able to estimate 

 the site accurately through comparison, after which 

 an occasional measurement kept his eye in prac- 

 tice. Age was determined by the use of the incre- 

 ment borer and by counting rings on nearby 

 stumps, and heights were measured with an Abney 

 level or by taping windfalls. Usually a minimum 

 of 9 or 10 measured determinations were made to 

 a township. The minimum site unit was about 

 640 acres. 



In recording site-quality classes, the area of sur- 

 veyed townships, by sections and rounded off to 

 the nearest 5 acres, was obtained from the original 

 General Land Office plats. The area of unsur- 

 veyed townships was determined by carefully 

 planimetering %-inch-to-the-mile lithographed 

 base maps of the national forests. Total national- 

 forest, Indian-reservation, and national-park areas 

 were determined by combining township area 

 data. This method was also used for several of 

 the counties, which were principally forested, and 

 for which complete area statistics were compiled. 

 The total area of the counties in which there was a 



large acreage of nonforest land was obtained from 

 statistics of the Bureau of the Census. 



The location of site determinations was platted 

 on a vellum township form (Form 974) and the 

 boundaries of site classes were shown in pencil on 

 the same form. These township maps were later 

 used in the office in the preparation of the county 

 site map. 



Two kinds of forest-type maps resulted from the 

 forest survey. Type maps, on a scale of 1 inch to 

 the mile and showing all of the type detail mapped 

 in the field, were prepared for each forested county 

 in the region. In the preparation of these maps, 

 the type data shown on the township field vellum 

 were traced on a brown-line print of the base 

 map of the county. A vandyke negative of the 

 tracing was then made, from which blue-line 

 prints are obtainable. The prints can be used 

 uncolored but are much more easily read if hand 

 colored with pencils or inks. The vandyke nega- 

 tive of a county type map is lent to anyone desir- 

 ing the map who has a blueprint machine at his 

 disposal, or is lent to a Portland blueprinting firm 

 from which the interested person can purchase the 

 prints. 



The other kind of map is a generalized forest- 

 type map, on a scale of % inch to the mile, litho- 

 graphed in colors to show the principal forest 

 types, and issued in four parts, covering the States 

 of Oregon and Washington. These are for sale 

 by the Pacific Northwest Forest Experiment Station 

 at a nominal price for each quarter. 



Compilation and Release of Data 



AREA COMPILATIONS 



The exact land area of each forested township in 

 the region and of each township within the 

 boundaries of all national forests, Indian reserva- 

 tions, and national parks, whether forested or not, 

 was determined. The land area of nonforested 

 townships outside any of the public forest units 

 was not determined except in a few counties where 

 complete area statistics were compiled. Complete 

 area statistics were compiled for all public forest 

 units. 



Timber volume and forest-type acreages were 

 compiled by ownership classes, and determined 

 from the most reliable sources. The ownership 



87 



