Cruisers worked in teams of three men. The lead man paced distances and navigated with a compass while a second man measured trees standing within one chain (20 m) of the transect center line; the third man recorded tree counts. Diameters were taken with Biltmore sticks or by ocular estimation depending on cruiser’s experience. Trees ⩾91 cm dbh were typically measured with the Biltmore stick. Inventory data were transferred from archived BIA
records (NARA, 1914–1922) to database files. Transects were digitally reconstructed from a BLM PLSS spatial data layer (USGS, 2010) using ESRI’s ArcMap software (release 10). The resultant polygons were linked to inventory records based on the recorded transect location and orientation. Tree density, basal area, diameter
distribution, and percent composition were computed for each transect. Mean dbh of 28 cm was assumed for trees 15–46 cm dbh inventoried from 1914 to 1919. This value Selleck Navitoclax was derived from the mean dbh weighted by tree count for the 201,555 trees of between 15–46 cm dbh of the same species recorded after 1919. After 1919, cruisers estimated mean dbh for trees 15–41 cm dbh and recorded trees 41-46 cm dbh in a separate size class. Mean dbh for each size class was used in basal area calculations, e.g., 53 cm dbh was used to calculate basal area for trees in the 50–55 cm dbh class. Mean values and standard deviation find more were weighted by transect area to accommodate the difference in area represented by an individual inventory record in the two sample periods, 1914–1919 (6.5 ha) and 1920–1922 (1.6 ha). Density of trees larger than 53 cm (21 in.) dbh is used here to characterize dry forests. The presence and abundance of trees >21 in. dbh is used to identify old-growth stands in interim old-growth guides (USFS, 1993). In addition, a 21-in. dbh
limit for tree harvesting was adopted as an interim measure in 1994 to slow harvest of old trees until more appropriate metrics could be identified (USFS, 1994). New metrics for identifying old trees and stands have been developed (Van Pelt, 2008) and are being adopted, but the 21-in. screen is still operational on timber sales in federal dry forests outside MycoClean Mycoplasma Removal Kit of the area of the Northwest Forest Plan. In this inventory, trees 50–55 cm dbh were recorded in one size class. For this analysis, half of those trees are assumed to be smaller than 53 cm dbh. Transects were assigned to previously defined habitat types to facilitate comparison of forest conditions along an inferred moisture gradient (from the driest sites where ponderosa pine is the climax species to dry and moist mixed-conifer sites). The use of widely accepted vegetation classifications facilitates communication with managers and stakeholders regarding sites where the results might be relevant. Habitat types identify areas that have comparable environmental and potential vegetative conditions (plant associations).