STAND DESCRIPTION

Plot Name: Reference Stand 29 (HJA)
Plot Size: 1 ha
Established: 1978
Remeasurements: 1983, 1988, 1995
Site Description
Latitude: 44.23
Longitude: 122.15
Elevation: 800 m
Aspect: N
Slope: 50-85%
Landform: Smooth footslope
Soil Parent Material: Red tuffs and breccias
Soil: Frissell Series
Plant Association: Tsuga heterophylla/Acer circinatum/ Polystichum munitum
Age Class: Old-growth

Soils:

Soils at two profile pits were described and sampled (see profile nos. 315 and 316 in the HJA Soils Data Base). Soils are fairly shallow and lack a B horizon. A horizons are about 6 to 12 inches thick and are comprised of very dark brown shotty loam to silt loam. A 12 in. thick transitional AC horizon contains dark yellowish brown to dark reddish brown loam to silty clay loam, containing about 10-15% shot and cobbles. The underlying C horizon is comprised of stony silty clay loam to silty clay. Soils at this site are well drained.

General Stand Description:

Tree data are obtained from stem map work and understory vegetation has been sampled in 5 circular plots within the reference stand. Since this is a high-elevational example of this habitat type, it contains some atypical species such as Vaccinium membranaceum, Vaccinium alaskaense, Rubus nivalis, and Pachistima myrsinites.
The tree layer is dominated by scattered old-growth Pseudotsuga menziesii and occasional Thuja plicata. Regeneration is shared between Tsuga heterophylla and Thuja plicata, with large numbers of smaller size-classes of each species. The small tree Taxus brevifolia is well represented in this stand with 13% cover.
The shrub layer is very dense with cover of Taxus, Tsuga, and Thuja regeneration. Acer circinatum cover is patchy, but totals more than 18%. The tall shubs are poorly represented in terms of cover. Low shrubs are dominated by Berberis nervosa.
The herb layer is very well developed. Dominance is shared by Polystichum munitum and Viola sempervirens. Tiarella unifoliata, Asarum caudatum, and Linnaea borealis also contribute much to the total herb cover.
Stand Structure and Composition
Live Tree Data at Last Measurement (1995)
Coarse Woody Debris (measured in 1995):
Ecosystem and Population Dynamics (measurements for most recent interval, 1988 to 1995)
Net Bole Production: 2.6 Mg/ha/yr
Annual mortality: 14.6 Mg/ha/yr
Percent of Trees Dying: total-0.8%/yr