STAND DESCRIPTION

Plot Name: Reference Stand 16 (HJA, Watershed 2)
Plot Size: 0.25 ha
Established: 1973
Remeasurements: 1976, 1983, 1988, 1993
Site Description
Latitude: 44.21
Longitude: 122.24
Elevation: 670 m
Aspect: SW
Slope: 60 to 70%
Landform: slightly convex backslope/shoulder below ridge crest
Soil Parent Material: colluvium from red and green breccia and andesite
Soil: Hapludalfs, Frissell Series
Plant Association: Tsuga heterophylla/Castanopsis chrysophylla
Age Class: Old-growth

Soils:

The soil profile at one pit was described and sampled (see profile no. 92 in the HJA Soils Data Base). The soil has a brown gravelly silt loam A1 horizon over a dark yellowish brown gravelly silty clay loam B2 horizon. This is a deep, well drained soil with a depth to saprolite of about 120 cm. The surface soil contains about 20% gravel, while the subsoil varies from 10 to 25% gravels and cobbles. Bulk density is 0.8 g/cc in the surface and 0.9 g/cc in the subsoil. Organic matter content is 3.7% in the A1 and 1.3% in the B2 horizon.

General Stand Description:

Several attributes indicate that RS 16 represents a mesic variety of the TSHE/CACH habitat type. Tree cover is denser than usual, shrub cover is lower than average, Xerophyllum tenax cover is greatly reduced in the herb layer, and moss cover is unusually high for this community. However, almost all species characteristically dominant in the TSHE/CACH habitat type are abundant in RS 16 except for Xerophyllum tenax.
The overstory is dominated by old-growth Pseudotsuga menziesii, with occasional Pinus lambertiana. Tsuga heterophylla also makes up part of the tree canopy and most of the immature tree layer. Pseudotsuga menziesii also occurs in the smaller size classes in the more open portions of the stand.
The tall shrub layer, dense and often impassable, is dominated by Castanopsis chrysophylla, Rhododendron macrophyllum, Acer circinatum, Taxus brevifolia, and Pseudotsuga menziesii. The low shrub layer, also dense, is dominated by Gaultheria shallon. Berberis nervosa is also quite common.
The herb layer is sparse. Linnaea borealis cover is 3.3% and Xerophyllum tenax is much less than average for the type. Moss cover is lower than on most other reference stands.
Stand Structure and Composition
Live Tree Data at Last Measurement
Coarse Woody Debris (measured in 1995):
Ecosystem and Population Dynamics (measurements for most recent interval, 1988-1993)
Net Bole Production: 3.9 Mg/ha/yr
Annual Mortality: 7.3 Mg/ha/yr
Percent of Trees Dying: total-1.1%/yr