Plot Name: Reference Stand 8 (HJA, Watershed 9)

Plot Size: 0.25 ha

Established: 1972

Remeasurements: 1976, 1981, 1986, 1991, 1997

Site Description

Latitude: 44.20

Longitude: 122.26

Elevation: 500 m

Aspect: W

Slope: 60 to 75%

Landform: pediment backslope

Soil Parent Material: colluvium from red breccia and basalt.

Soil: Lithic Dyrstrochrepts, Flunky Series

Plant Association: Pseudotsuga menziesii-Tsuga heterophylla/Corylus cornuta var. californica

Age class: Old-growth

Soils:

The soil profile at one pit site was described and sampled (see profile no. 86 in the HJA Soils Data Base). The soil was found to be shallow, stony, and well drained. The soil texture in the surface soil (0-15 cm) was very gravelly loam and in the subsoil (about 15-50 cm) it was a very gravelly sandy loam. Stone content was 65% gravels and cobbles. Pumice grains and charcoal were also present. Soil depth is generally 50 cm or less. Bulk density was estimated to be 0.9 g/cc and organic matter content was 15.0% in the surface and 5.0% in the subsoil.

General Stand Description:

This reference stand is similar to RS 1 and both are good representatives of the PSME-TSHE/COCOCA habitat type described by Dyrness et al. (1974). The pricipal difference is that this reference stand and RS 1 have less cover of Gaultheria shallon than average. Berberis nervosa coverage is below average as well.

RS 8 has a partially open canopy which varies markedly in height and depth due to the dominance of old-growth Pseudotsuga menziesii over emergent Pseudotsuga menziesii, Tsuga heterophylla, Taxus brevifolia, Calocedrus decurrens, and Acer macrophyllum in large openings. Immature trees are largely Pseudotsuga menziesii, with Tsuga heterophylla second in importance.

In addition to the immature conifers, the tall shrub layer contains an abundance of the dominant shubs Acer circinatum and Corylus cornuta var. californica and moderate amounts of Rhododendron macrophyllum, Cornus nuttallii, and Taxus brevifolia. Low shrubs are also well represented with Berberis nervosa being the most abundant species.

The herb layer was found to be unusually rich, with a total of 30 species being recorded. Polystichum munitum, Whipplea modesta, Linnaea borealis, Synthyris reniformis, Achlys triphylla, and Vancouveria hexandra contribute most of the cover.

Stand Structure and Composition

Live Tree Data at Last Measurement

Basal area: 96.9 m²/ha
PSME-91.0 m²/ha
Stem numbers: 684/ha
PSME-520/ha
Diameter distribution:
median-13.7 cm
quadratic mean-42.5 cm
maximum-156.9 cm.
Age: not available
Height (measurements within the last 20 years): not available
Volume: 1624.4 m³/ha
PSME-1569.4 m³/ha
Biomass: 934.2 Mg/ha
PSME-903.8 Mg/ha

Coarse Woody Debris (measured in 1982):

The total volume and mass of logs on Reference Stand 8 are 339 m³/ha and 71 Mg/ha, respectively. The volume and mass of standing dead trees (snags) are 232 m³/ha and 81 Mg/ha, respectively.

Ecosystem and Population Dynamics (measurements for most recent interval, 1991-1997)

Net Bole Production: 3.5 Mg/ha/yr

Annual Mortality: 0.0

Percent of Trees Dying: Total-0.4%/yr (none were uprooted or broken)

PSME-0.4%/yr.