STAND DESCRIPTION

Plot Name: Reference Stand 5 (HJA)
Plot Size: 0.25 ha
Established: 1972
Remeasurements: 1976, 1981, 1986, 1990, 1996
Site Description
Latitude: 44.22
Longitude: 122.20
Elevation: 920 m
Aspect: NW
Slope: 0 to 30%
Landform: undulating bench with a complex pattern of gently to moderately sloping ridge spurs, saddles, and pediment surfaces.
Soil Parent Material: andesitic alluvium-colluvium over silty material.
Soil(s): Level Saddle- Dystrochrepts, Carpenter Series, Pediment Backslope-Haplumbrepts, Frissell Series
Plant Association: Tsuga heterophylla-Abies amabilis/Rhododendron macrophyllum-Berberis nervosa.
Age class: Old-growth

Soils:

Soils at two profile pits were described and sampled (see profile nos. 82 and 83 in the HJA soils Data Base). The Carpenter soil was uniformly a gravelly silt loam with gravel and cobble content of 20 to 50 percent. The Frissell soil was gravelly loam in texture, with 30-50 percent gravel content. Soil depth to parent material was about 1 m for both soils. Both soils had a bulk density of about 0.6 g/cc in the surface and 0.8 g/cc in the subsoil. Organic matter content in the Carpenter soil 3.3% in the surface and 0.7% in the subsoil. For the Frissell soil the similar values were 5.6% and 3.4%.

General Stand Description:

This reference stand has very few plant species--there are only 23 species in all layers combined. The stand is a fair representative of the TSHE-ABAM/RHMA-BENE habitat type of Dyrness et al. (1974). Despite the fact Acer circinatum is more abundant, the species present are characteristic of the TSHE-ABAM/RHMA-BENE habitat type. The tree layer in RS 5 lacks Abies amabilis, but the species has been recorded in plots adjacent to the stand in the same habitat type.
The tree canopy of this stand is composed of old-growth Pseudotsuga menziesii and emergent Tsuga heterophylla. Immature trees are dominated by Tsuga heterophylla and the ever-present Taxus brevifolia. Both species contribute greatly to the cover of the tall shrub layer.
The tall shrub layer is dominated by Rhododendron macrophyllum and Acer circinatum, which combine to create a nearly impassable shrub layer. Beneath the tall shrubs is a well-developed low shrub layer dominated by Berberis nervosa.
The herb stratum is poorly developed. Cover is only about 4%, and no species is clearly dominant. Chimaphila umbellata is the most abundant herb species. The moss layer is nearly nonexistent.
Stand Structure and Composition
Live Tree Data at Last Measurement (1996)
Coarse Woody Debris (measured in 1982, 1989):
Ecosystem and Population Dynamics (measurements for most recent interval, 1990-1996)
Net Bole Production: 3.9 Mg/ha/yr
Annual Mortality: 20.2 Mg/ha/yr
Percent of Trees Dying: Total-1.1%/yr (40% were broken)