A total of 194 permanent vegetation sampling plots were established (133 plots on watershed 1, 61 plots on watershed 3). The undisturbed vegetation present on these plots was recorded during the summer of 1962. Herbage cover of shrubs and trees was estimated by species on a milacre (6.6 feet square) plot. Cover of herbs and grasses was estimated on nine 1.1-foot-square plots at each location. Percent cover and frequency were computed for each plant species present. Prior to logging, plots were assigned to one of the six plant communities and one of six soil types, reflecting parent material, depth, and profile development (Rothacher et al. 1967, Dyrness 1969). Both watersheds were logged and broadcast burned: WS1 over a 4-yr period (1962-1966) and WS3 in 1962-1963 (see site description).
Circular plots of 250 m sq were established in 1979 (WS3) and 1980 (WS1), 16 and 14 yr after broadcast burning. Plot centers coincided with the locations of permanent understory quadrats established in 1962, prior to harvest (Dyrness 1973, Halpern 1988, 1989). In WS1, 133 plots were spaced at 30.5-m intervals along six widely spaced transects oriented perpendicular to the main stream channel. In WS3, 61 plots were similarly spaced along two to four transects per harvest unit. Because the objective was to characterize development of upland forests, plots that fell in perennial stream channels were not established, nor were plots that fell on rock outcrops or on roads in WS3. Sample plots comprise ~4% of the harvested areas of the two watersheds. Circular plots include one central subplot (2 by 2 m) consistently measured from 1962 to present, and 4 square subplots on outer edge of circular plot were measured from 1979-1987.
Plot locations were determined in 2004 using a differentially corrected Trimble GPS. Direct readings were made on 91 plots and the remaining locations were interpolated. Elevation, aspect, and slope were determined from GPS locations and a 10-m digital elevation model and later a 1-m LIDAR coverage. (Lienkaemper 2005, Valentine 2009). Mean annual insolation, considering both topographic shading and cloud cover, was extracted from earlier modeling work by Jonathan Smith (2002).
Rothacher, Jack; Dyrness, C. T.; Fredriksen, Richard L. 1967. Hydrologic and related characteristics of three small watersheds in the Oregon Cascades. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 54 p.
Lutz, James A. 2005. The contribution of mortality to early coniferous forest development. Seattle, WA: University of Washington. 95 p. M.S. thesis.
On each subplot ocularly estimate cover of trees (less than 20 m), shrubs (< 2 m) herbs, logs, litter, ground, stones. For all woody shrubs and trees, stems are tagged and counted,and diameters measured at ground level or at DBH (depending on tag location which is based on stem size).
For Plant community and Soil Type definitions see:
For further soil type descriptions see: Dyrness, C. T. 1969. Hydrologic properties of soils on three small watersheds in the western Cascades of Oregon. Res. Note PNW-111. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 17 p.
