STAND DESCRIPTION
- Plot Name: Reference Stand 24 (Hagan Block RNA)
- Plot Size: 1.0 ha
- Established: 1977
- Remeasurements: 1983, 1988, 1994
- Site Description
- Latitude: 44.17
- Longitude: 122.42
- Elevation: 610 m
- Aspect: NW
- Slope: 45-60%
- Landform: Lower 1/3 slope off a midslope subridge
- Soil Parent Material: Unknown
- Soil: Unknown
- Plant Association: Pseudotsuga menziesii/Polystichum munitum-
Oxalis oregana
- Age Class: Second-growth
Soils:
- No information at present.
General Stand Description:
This is a stand of second-growth Douglas-fir, 75 to 105
years old, which came in after a fire. This is a seral
forest community leading to the climax association, Tsuga
heterophylla/Polystichum munitum-Oxalis oregana.
Characteristic species of the oxalis community are numerous
here. They include Blechnum spicant, Adiantum pedatum,
Athyrium filix-femina, Montia sibirica, and Thalictrum
occidentale, all common to very wet microclimates. The
vegetation of this reference stand is closely similar to that
of the coastal Oxalis habitat types.
The tree layer is dominated by a dense canopy of
Pseudotsuga menziesii with 75-80% cover. The primary
reproducing tree species of the site is Tsuga heterophylla.
Local areas also have considerable Alnus rubra cover (mostly
adjacent to the wetter areas and depressions near a stream
channel on one side of the plot).
RS 24 has a well developed shrub layer dominated by the
tall shrub Acer circinatum and the low shrub Berberis nervosa
(and sometimes Gaultheria shallon). The shrub layer of the
more typical old-growth TSHE/POMU-OXOR stand located on
footslopes and low elevation sideslopes of notherly aspects
includes only spotty and minor cover of these shrub species.
The herb layer of RS 24 is typical of the oxalis
community in having high diversity, as well as dominance by
the two diagnostic species, Polystichum munitum and Oxalis
oregana.
- Stand Structure and Composition
- Live Tree Data at Last Measurement
- Basal Area: 58.1 m2/ha
- PSME-56.4 m2/ha
- TSHE-1.2 m2/ha
- Stem Numbers: 276/ha
- PSME-216/ha
- TSHE-49/ha
- Diameter Distribution:
- median-45.1 cm
- quadratic mean-51.8 cm
- maximum-117.0 cm
- Age: not available
- Height (measurements within the last 20 years):
- PSME ave.=48.0 m (n=51, quadratic mean diam.=65.5 cm.) max.=64.7 m
- Volume: 805.6 m3/ha
- PSME-789.4 m3/ha
- TSHE-10.5 m3/ha
- Biomass: 460.0 Mg/ha
- PSME-452.4 Mg/ha
- TSHE-5.0 Mg/ha
- Coarse Woody Debris (measured in 1977):
The total volume and mass of logs is 492 m3/ha and 86
Mg/ha, respectively. The volume and mass of standing dead
trees (snags) is 151 m3/ha and 35 Mg/ha, respectively.
- Ecosystem and Population Dynamics (measurement for most recent
interval, 1988-1994)
- Net Bole Production: 5.9 Mg/ha/yr
- Annual Mortality: 0.9 Mg/ha/yr
- Percent of Trees Dying: total-0.8%/yr