STAND DESCRIPTION

Plot Name: Reference Stand 22 (HJA)
Plot Size: 1.0 ha
Established: 1977
Remeasurements: 1983, 1988, 1993
Site Description
Latitude: 44.27
Longitude: 122.14
Elevation: 1290 m
Aspect: S
Slope: 15-25%
Landform: Midslope bench on Carpenter Mountain
Soil Parent Material: Andesite colluvium mixed with volcanic ash and pumice
Soil: Blue River Series
Plant Association: Abies amabilis/Vaccinium membranaceum/ Xerophyllum tenax
Age Class: Old-growth and mature

Soils:

Soils at two profile pits were described and sampled (see profile nos. 309 and 310 in the HJA Soils Data Base). These soils are moderately deep and well drained and are derived from andesite colluvium with volcanic ash influence. The surface soil, 5 to 10 inches in depth, is very dark brown silt loam with fine granular structure. The underlying B horizon is made up of dark brown silty clay loam or clay loam with 10 to 35% of gravels and cobbles and medium to coarse subangular blocky structure. The C horizon is encountered at 2.5 to 3 ft. in depth. It is comprised of massive, stony silty clay loam or clay loam. In profile 309 the C horizon was described as a silica-cemented durapan.

General Stand Description:

This stand is located on a bench on the slopes of Carpenter Mountain. It is a very homogenous stand of old- growth (450+ years) and mature (300-400 years-old) Douglas- fir and noble fir. The ABAM/VAME/XETE association occurs over the entire bench with rapid transitions to the ABAM/TIUN habitat type on the opposing slopes of the headwaters of McRae Creek and to the ABAM/ACTR habitat type on the steep slope of the mountain above the bench.
The tree canopy is quite dense and composed of the dominants Pseudotsuga menziesii and Abies procera. Tree size-class distribution indicates Abies amabilis is the primary reproducing tree species. Abies amabilis, as well as Tsuga heterophylla and T. mertensiana, are emergent is some areas. Tsuga mertensiana is patchy, with relatively high cover in some areas.
The shrub layer, typical of upper-elevation beargrass communities, is poorly developed. Scattered Vaccinium membranaceum and Rubus lasiococcus are the only common shrub species.
The herb layer is extremely well developed with almost three-quarters of the stand area covered. Most of the herb cover (69%) is provided by the dominant Xerophyllum tenax. Because beargrass is so well developed, other herb and low shrub species are restricted in their growth and development. However, diversity is still moderate. Other common herbs include Pteridium aquifolium, Clintonia uniflora, and Achlys triphylla.
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: 4.5 Mg/ha/yr
Annual Mortality: 15.9 Mg/ha/yr
Percent of Trees Dying: 1.4%/yr (17.8% were uprooted)