STAND DESCRIPTION

Plot Name: Reference Stand 23 (HJA)
Plot Size: 1.0 ha
Established: 1977
Remeasurements: 1983, 1988, 1993
Site Description
Latitude: 44.23
Longitude: 122.12
Elevation: 1020 m
Aspect: NE
Slope: 30-55%
Landform: Lower 1/3 smooth slope (footslope of Lookout Mt.)
Soil Parent Material: Andesite Colluvium
Soil: Carpenter Series
Plant Association: Abies amabilis/Vaccinium alaskaense/ Cornus canadensis
Age class: Old-growth

Soils:

Soils at two profile pits were described and sampled (see profile nos. 311 and 312 in the HJA Soils Data Base). Surface soils are dark brown gravelly loam. The subsoil (B2 horizons) is made up of dark brown gravelly to very stony clay loam. Depth to B2 horizons averages 16 inches and they extend to almost 3 feet before parent material is encountered. The surface soil contains 20-30% gravels and cobbles, and the B2 35-50% gravels, cobbles, and larger stones. Soils are well drained and are formed in deep deposits of andesite colluvium.

General Stand Description:

The reference stand is T-shaped with one 50 x 50 m block forming the stem and three 50 x 50 m blocks forming the cross member uphill from the stem. The ABAM/VAAL/COCA community prevails over all the reference stand except for the gradual shift in the lower one-third of the basal stem of the T-shaped stand which slowly gives way to the high elevation form of the TSHE/ACCI/POMU community adjacent to the stream.
The tree canopy of this stand is moderately open and is composed of dominant, large Pseudotsuga menziesii and Thuja plicata. These are very old and broken-crowned trees and are members of an age-class presently well distributed throughout the stand. The dominant reproducing tree species is Tsuga heterophylla, present in virtually all size-classes up to 130 cm dbh. Of secondary importance is the reproduction of Abies amabilis. The small size classes of Abies amabilis are well represented, indicating the future importance of this species in the climax stand, along with T. heterophylla. Abies grandis is of poor quality and Pinus monticola is commonly found but is rarely important in terms of cover or abundance.
The tall shrub layer is well developed with Rhododendron macrophyllum, Vaccinium alaskaense, and Acer circinatum each in excess of 12% cover. Vaccinium membranaceum and V. parvifolium are also common in the shrub layer but neither typically has high cover. The low shrub layer is less well developed with only a small amount of cover by a very few species. Rubus ursinus is the most abundant, with Pachistima myrsinites also common.
The herb layer is quite diverse with many species having moderate cover. Cornus canadensis is most abundant. Clintonia uniflora, Smilicina stellata, Viola sempervirens, Linnaea borealis, Tiarella unfifoliata, and Chimaphila umbellata are also common with moderate abundance. Xerophyllum tenax also has 3.3% cover here. The moss layer is less developed than in mesic habitats at lower elevations. The dominant species, Rhytidiopsis robusta, is a good indicator of upper-elevation, cooler habitat types.
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: 2.3 Mg/ha/yr
Annual Mortality: 0.7 Mg/ha/yr
Percent of Trees Dying: total-0.5%/yr