PURPOSE
To determine the canopy coverage and frequency of each plant species and total species coverage, richness, and diversity of Tully soil uplands, mid-slopes, and Florence soil lowlands in each watershed.
LOCATIONS OF SAMPLING STATIONS
Sampling is on Florence, Tully, and mid-slope topographical positions in watersheds 004A, 004B, N04A, N04D, 020B, 020D, N20A, N20B, 001D, and N01B. Only Florence and Tully soils are sampled on watersheds 001C and N01A. Only upland Florence sites are sampled on watersheds 002C and 002D.
Two 50 m lines have been established at each Tully soil, Florence soil, and mid-slope position in each watershed (6 sites x 2 transect lines = 12 transects/watershed,(Fig. 22). Each transect is marked by a 1.5 m conduit at each end (see maps, Figs.23-33). ( Fig. 23), ( Fig. 24),( Fig. 25),( Fig. 26), ( Fig. 27),( Fig. 28), ( Fig. 29), ( Fig. 30), ( Fig. 31), ( Fig. 32),( Fig. 33)
Five 10 m2 circular plots are located on each 50 m transect at the 5, 15, 25, 35, and 45 m positions. The center of each plot is marked by conduit projecting 10-20 cm above the soil surface. A plastic flag is placed in each conduit. For record- keeping, each line for each soil type is marked with a "F" for Florence, "T" for Tully, or "S" for slope position and then labelled A, B, C, or D. The five plots on each line are numbered from 1 to 5 with number 1 usually to the north or west. A 50 m transect for measuring aboveground biomass is placed 4 m to the side of each species composition line. The conduit for the species composition transects are painted red, while the biomass conduits are painted yellow.
SAMPLING HISTORY
No slope sites were sampled prior to 1992. Through 1991, watersheds 020B, N20B, N01B, 001D, 001C, N04D, and 004B were sampled on both Florence and Tully soil sites and watersheds 002D, 002C, 004A, 004D, and 004F were sampled on Florence soil sites only.
FREQUENCY OF SAMPLING
All plots along each transect line are sampled twice during the growing season. The first sampling is conducted in late-May and second is conducted in mid- to late-August. A separate, late- April to early-May sampling is conducted for only the early annuals and other species that senesce early in the season.
VARIABLES MEASURED
Species presence and canopy coverage class for each species from which frequency can also be computed. See Figs. 34a, b for sample data sheets.
METHODS
To assess plant species composition all plant species in a 10 m2 circular plot are recorded. A surveyor's pin is placed in the conduit marking the center of the plot. Attached to the pin is a 1.78 m long chain with a ring at the free end. The observer holds the ring on a finger, pulls the chain taut, and walks in a circle around the circumference of the plot defined by the chain radius. On each plot canopy coverage of all species are recorded on the field data sheets according to the following canopy coverage classes (modified after Daubenmire, 1959. Northwest Sci. 33: 43- 66):P Class Canopy cover Mid-point
1 0 - 1% 0.5%
2 1 - 5% 3.0%
3 5 - 25% 15.0%
4 25 - 50% 37.5%
5 50 - 75% 62.5%
6 75 - 95% 85.0%
7 95 - 100% 97.5%
Canopy coverage is defined as the area within lines connecting the extremities of the plant canopy represented by that species. It does not measure yield or leaf area. The value of this definition of canopy and the use of coverage classes is the greater agreement between ratings by different workers or by the same worker at different times than would be possible by other visual canopy measures. Nonetheless, it is important that new workers be trained with someone experienced in the method to avoid investigator bias.
FORM OF DATA OUTPUT
Canopy coverage is computed for each Tully, Florence, and slope topographical position by averaging the mid-points of the cover class ratings for each species for the 20 plots at each sampling period. Most species are only rated during one of the two sampling periods, but for those species rated at both sampling dates, the ratings on the date at which that species' canopy is more fully developed is retained for analysis.
Frequency is the percent of the 20 plots in which the species occurred.
