Print Report
CEGL000287 Abies grandis - Tsuga heterophylla / Polystichum munitum Forest
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Grand Fir - Western Hemlock / Western Swordfern Forest
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: Giant Pseudotsuga menziesii old-growth trees dominate the overstory of these closed-canopy, valley bottom and river terrace forests. Abies grandis, Tsuga heterophylla, and Thuja plicata are the dominant understory trees, usually with a few individuals in the canopy. Giant (>6 feet tall) Polystichum munitum dominate the understory, usually with over 60% cover. Corylus cornuta, Oemleria cerasiformis, Taxus brevifolia, and Acer macrophyllum can form a subcanopy in moist alluvial soils or rocky areas. Vaccinium parvifolium, Mahonia nervosa, and Gaultheria shallon are occasional low shrubs, while Oxalis oregana, Trillium ovatum, Maianthemum dilatatum, Rubus ursinus, and Prosartes smithii are forbs which can be locally important. In seeps and wet areas along streams, Adiantum pedatum is found. Both fire and flooding are important processes in these habitats, although both occur infrequently. The terraces are usually well above the river, impacted only by 100+ year flood intervals, but dependent on the deep alluvial deposits for their productivity. Most of the old-growth trees present have evident fire scars, although the presence of 100-200 year old, fire-sensitive Thuja plicata, Tsuga heterophylla and Abies grandis individuals is evidence of a fairly long fire-return interval. This type is known from medium streams to large rivers, but rarely along small or seasonal streams.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: No Data Available
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: Giant Pseudotsuga menziesii old-growth trees dominate the overstory of these closed-canopy, valley bottom and river terrace forests. Abies grandis, Tsuga heterophylla, and Thuja plicata are the dominant understory trees, usually with a few individuals in the canopy. Giant (>6 feet tall) Polystichum munitum dominate the understory, usually with over 60% cover. Corylus cornuta, Oemleria cerasiformis, Taxus brevifolia, and Acer macrophyllum can form a subcanopy in moist alluvial soils or rocky areas. Vaccinium parvifolium, Mahonia nervosa (= Berberis nervosa), and Gaultheria shallon are occasional low shrubs, while Oxalis oregana, Trillium ovatum, Maianthemum dilatatum, Rubus ursinus, and Prosartes smithii (= Disporum smithii) are forbs which can be locally important. In seeps and wet areas along streams, Adiantum pedatum is found.
Dynamics: Both fire and flooding are important processes in these habitats, although both occur infrequently. The terraces are usually well above the river, impacted only by 100+ year flood intervals, but dependent on the deep alluvial deposits for their productivity. Most of the old-growth trees present have evident fire scars, although the presence of 100-200 year old, fire-sensitive Thuja plicata, Tsuga heterophylla and Abies grandis individuals is evidence of a fairly long fire-return interval.
Environmental Description: This type is known from medium streams to large rivers, but rarely along small or seasonal streams.
Geographic Range: Known from river terraces in western Oregon and southwestern Washington. To the south, higher natural fire frequencies result in the replacement of Abies grandis, Thuja plicata and Tsuga heterophylla by fire resistant Quercus, Pinus, Chamaecyparis, and Calocedrus species. To the north with fire more infrequent, western red cedar completely dominates these communities. Primarily found in and along the margins of the Willamette Valley, the type extends north to Olympia, and occasionally can be found in the adjacent Oregon Coast Range and West Cascade ecoregions. In the west Cascades, most habitat is now under water created by major dams.
Nations: US
States/Provinces: OR, WA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.684035
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: G2
Greasons: No Data Available
| Type | Name | Database Code | Classification Code |
|---|---|---|---|
| Class | 1 Forest & Woodland Class | C01 | 1 |
| Subclass | 1.B Temperate & Boreal Forest & Woodland Subclass | S15 | 1.B |
| Formation | 1.B.2 Cool Temperate Forest & Woodland Formation | F008 | 1.B.2 |
| Division | 1.B.2.Nd Vancouverian Forest & Woodland Division | D192 | 1.B.2.Nd |
| Macrogroup | 1.B.2.Nd.3 Western Hemlock - Sitka Spruce - Redwood Rainforest Macrogroup | M024 | 1.B.2.Nd.3 |
| Group | 1.B.2.Nd.3.c Douglas-fir - Western Hemlock / Salal Rainforest Group | G240 | 1.B.2.Nd.3.c |
| Alliance | A3377 Western Hemlock - Douglas-fir / Salmonberry Mesic Forest Alliance | A3377 | 1.B.2.Nd.3.c |
| Association | CEGL000287 Grand Fir - Western Hemlock / Western Swordfern Forest | CEGL000287 | 1.B.2.Nd.3.c |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: No Data Available
- Bourgeron, P. S., and L. D. Engelking, editors. 1994. A preliminary vegetation classification of the western United States. Unpublished report. The Nature Conservancy, Western Heritage Task Force, Boulder, CO. 175 pp. plus appendix.
- Kagan, J. S. 1987c. Draft species management guide for Astragalus robbinsii var. alpiniformis. Challenge grant funding with USDA Forest Service. Oregon Natural Heritage Data Base, The Nature Conservancy, Portland.
- Kagan, J. S., J. A. Christy, M. P. Murray, and J. A. Titus. 2004. Classification of native vegetation of Oregon. January 2004. Oregon Natural Heritage Information Center, Portland. 52 pp.
- Parker, K. 1982. Analysis of understory vegetation of a low elevation old growth forest in the Sandy River Gorge. Unpublished undergraduate thesis, Reed College, Portland, OR. 42 pp.
- WNHP [Washington Natural Heritage Program]. 2018. Unpublished data files. Washington Natural Heritage Program, Department of Natural Resources, Olympia, WA.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.