STAND DESCRIPTION

Plot Name: Reference Stand 7 (HJA)
Plot Size: 0.25 ha
Established: 1971
Remeasurements: 1976, 1981, 1986, 1990, 1996
Site Description
Latitude: 44.21
Longitude: 122.25
Elevation: 490 m
Aspect: N
Slope: 50-60%
Landform: uneven pediment backslope
Soil Parent Material: alluvium-colluvium from red tuff and breccia
Soil: Haplumbrepts, Frissell Series
Plant Association: Tsuga heterophylla/Polystichum munitum- Oxalis oregana
Age class: Old-growth

Soils:

The soil at one profile pit was described and sampled (see profile no. 85 in the HJA Soils Data Base). A 30 cm thick layer of gravelly silt loam (25% gravel) overlies finer textured (silty clay loam) horizons which have 15 to 40% gravel and cobbles. Soil depth to the very weathered parent material is approximately 1 m. Bulk density of the soil was estimated to be about 0.9 g/cc. Organic matter content was 5.4% in the surface soil and about 0.9% in the subsoil.

General Stand Description:

This reference stand is one of two (the other is RS 19) that represent the moist end of the gradient of low elevation stands in the H.J. Andrews Forest. RS 7 is well representative of the TSHE/POMU-OXOR habitat type of Dyrness et al. (1974). Reduced shrub cover is characteristic of low- elevation communities with abundant moisture in this area. Dominance by the two herbs, Polystichum munitum and Oxalis oregana, conclude the classification of this reference stand. The TSHE/POMU-OXOR community at the warm-moist end of the existing gradients remains fairly constant throughout the Pacific Northwest, though the overstory characteristics may change (Franklin and Dyrness 1973).
The tree canopy is dominated by old-growth Pseudotsuga menziesii. Tsuga heterophylla is emergent and Thuja plicata is common throughout. Tsuga heterophylla and Thuja plicata comprise the great majority of immature trees and most of the tall shrub stratum in this reference stand.
The tall shrub layer contains 8.3% Acer circinatum cover, as well as abundant Taxus brevifolia and Cornus nuttallii. The low shrub layer is poorly developed and scattered.
The herb layer is dominated by large patches of Oxalis oregana and scattered clumps of Polystichum munitum. Linnaea borealis, Coptis laciniata, and Tiarella unifoliata are also common. The moss layer is extremely well developed and has seven species and more than 50% cover. The most common moss species is Eurhynchium oreganum.
Stand Structure and Composition
Live Tree Data at Last Measurement (1996)
Coarse Woody Debris (measured in 1982):
Ecosystem and Population Dynamics (Measurements for most recent interval, 1990-1996)
Net Bole Production: 3.4 Mg/ha/yr
Annual Mortality: 0.7 Mg/ha/yr
Percent of Trees Dying: Total-0.4% (50% were broken and 50% uprooted)