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CEGL000468 Thuja plicata - (Abies grandis) / Polystichum munitum Forest
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Western Red-cedar - (Grand Fir) / Western Swordfern Forest
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This forest association occurs primarily in the Puget Sound Basin in northwestern Washington and adjacent British Columbia. Stands are relatively small in area and are restricted to very specific environments in the rainshadow of the Olympic Mountains and Vancouver Island. The climate is drier than surrounding coastal mountain areas, with average annual precipitation ranging from as low as 46 cm in the San Juan Islands to 90 cm in the Puget Lowlands, with a pronounced summer dry season. Valleys where these forests are found are protected from the dry summer winds and have relatively low summer temperatures. Soils are loamy sands to sandy loams, with weakly developed profiles, and soil moisture is high most of the year. These tall conifer forests are dominated by Thuja plicata and Abies grandis. Tsuga heterophylla is also common, occurring in most stands, but in less abundance and does not regenerate. Tree regeneration is relatively sparse, with the dominant trees each averaging 64 saplings and seedlings per hectare. Stands that have been disturbed by logging often have an abundant tree subcanopy and shrubby layer of the seral, broad-leaved deciduous trees Acer macrophyllum and Alnus rubra. These deciduous species are not present in undisturbed stands. The understory is strongly dominated by the perennial fern Polystichum munitum, which averages 43% cover and often the fronds have a 2-m spread. Scattered individuals of several shrub species also occur, such as Symphoricarpos albus and Vaccinium parvifolium, but none have greater than 2% cover. Mosses are abundant on logs and average 15% cover. Diagnostic of this forest association is the dominance of Thuja plicata and Abies grandis in the tree canopy and Polystichum munitum in the understory.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: First described in the U.S. by Fonda and Bernardi (1976) from Sucia Island.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: This forest association is dominated by the evergreen needle-leaved trees Thuja plicata and Abies grandis. These species have average densities of 148 and 90 trees per hectare (>10 cm in diameter), respectively. Pseudotsuga menziesii is often present as scattered large individuals in the upper canopy, and may be codominant in some stands, but is never regenerating. Tsuga heterophylla is occasionally present with low cover. Tree regeneration may be relatively sparse, with the dominant trees each having an average of 64 saplings and seedlings per hectare. The understory is strongly dominated by the perennial fern Polystichum munitum, which averages 43% cover or more, and often the fronds have a 2-m spread. Scattered individuals of several shrub species occur, but none have greater than 2% cover. Mosses are abundant on logs, and average 15% cover. Stands that have been disturbed by logging often have an abundant tree subcanopy and shrubby layer of the seral, broad-leaved deciduous trees Acer macrophyllum and Alnus rubra.
Dynamics: No Data Available
Environmental Description: This association occurs primarily in the Puget Sound basin, an area in the rainshadow of the Olympic Mountains. The climate in this rainshadow is drier than surrounding coastal mountain areas, with average annual precipitation ranging from as low as 46 cm in the San Juan Islands to 75 cm in the Puget lowlands, with a pronounced summer dry season. Temperatures are strongly moderated by oceanic influence. Geologically, the Puget Trough includes the Puget Sound basin and extends into the Willamette Valley of north-central Oregon. Puget Sound basin is a depressed, glaciated region which is now partially submerged. This basin contains many lakes and poorly drained depressions underlain by glacial drift.
Valleys and gentle slopes where this association is found are protected from dry summer winds and have relatively low summer temperatures. Soils are loamy sands to sandy loams, with weakly developed profiles, and soil moisture is high most of the year. These are moderately moist sites within the dry climatic conditions of the northern Puget Trough. Polystichum munitum is most abundant on sites with fertile soils that are well-watered from upslope moisture.
Valleys and gentle slopes where this association is found are protected from dry summer winds and have relatively low summer temperatures. Soils are loamy sands to sandy loams, with weakly developed profiles, and soil moisture is high most of the year. These are moderately moist sites within the dry climatic conditions of the northern Puget Trough. Polystichum munitum is most abundant on sites with fertile soils that are well-watered from upslope moisture.
Geographic Range: Found almost exclusively in the San Juan Islands and vicinity (San Juan, Skagit, and Clallam counties) and into adjacent British Columbia.
Nations: CA,US
States/Provinces: BC, OR, WA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.689671
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: G1
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.f Western Hemlock - Sitka Spruce North-Central Pacific Rainforest Group | G751 | 1.B.2.Nd.3.f |
| Alliance | A3609 Grand Fir - Sitka Spruce - Western Red-cedar Forest Alliance | A3609 | 1.B.2.Nd.3.f |
| Association | CEGL000468 Western Red-cedar - (Grand Fir) / Western Swordfern Forest | CEGL000468 | 1.B.2.Nd.3.f |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: >< Pseudotsuga menziesii-Abies grandis-Tsuga heterophylla/Polystichum munitum (Agee 1987)
= Thuja plicata - Abies grandis / Polystichum munitum (Chappell 1997)
= Thuja plicata - Abies grandis / Polystichum munitum (Chappell 2006b) [10 plots]
= Thuja plicata - Abies grandis / Polystichum munitum (Fonda and Bernardi 1976)
= Thuja plicata - Abies grandis / Polystichum munitum Forest Association (Rocchio et al. 2012)
= Thuja plicata-(Abies grandis)/Polystichum munitum (Meidinger et al. 2005) [PNWCOAST_212]
> CDF mm /06 (Green and Klinka 1994)
> CDF mm /12 (Green and Klinka 1994)
= Thuja plicata - Abies grandis / Polystichum munitum (Chappell 1997)
= Thuja plicata - Abies grandis / Polystichum munitum (Chappell 2006b) [10 plots]
= Thuja plicata - Abies grandis / Polystichum munitum (Fonda and Bernardi 1976)
= Thuja plicata - Abies grandis / Polystichum munitum Forest Association (Rocchio et al. 2012)
= Thuja plicata-(Abies grandis)/Polystichum munitum (Meidinger et al. 2005) [PNWCOAST_212]
> CDF mm /06 (Green and Klinka 1994)
> CDF mm /12 (Green and Klinka 1994)
- Agee, J. K. 1987. The forest of San Juan Island National Historic Park. Unpublished report prepared by the University of Washington for the USDA National Park Service. Report CPSU/UW 88-1. 83 pp.
- BCMFRB [British Columbia Ministry of Forests Research Branch]. 2003a. Vegetation classification hierarchy: BECMaster May 2003. British Columbia Ministry of Forests, Victoria, BC.
- 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.
- Chappell, C. 1994. Natural forests of the Puget Lowland, Washington. Northwest Science Abstract.
- Chappell, C. B. 1997. Terrestrial forested plant associations of the Puget Lowland. Draft report. Washington Natural Heritage Program, Washington Department of Natural Resources, Olympia. 36 pp.
- Chappell, C. B. 2006b. Upland plant associations of the Puget Trough ecoregion, Washington. Natural Heritage Report 2006-01. Washington Department of Natural Resources, Natural Heritage Program, Olympia, WA. [http://www.dnr.wa.gov/nhp/refdesk/communities/pdf/intro.pdf]
- Fonda, R. W., and J. A. Bernardi. 1976. Vegetation of Sucia Island in Puget Sound, Washington. Bulletin of the Torrey Botanical Club 103(3):99-109.
- Franklin, J. F., and C. T. Dyrness. 1973. Natural vegetation of Oregon and Washington. General Technical Report PNW-8. USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Portland, OR. 417 pp.
- Green, R. N., and K. Klinka. 1994. A field guide to site interpretation for the Vancouver Forest Region. British Columbia Ministry of Forests. ISSN 0229-1622 Land Management Handbook 28. 285 pp.
- Meidinger, D., C. Chappell, C. Cadrin, G. Kittel, C. McCain, K. Boggs, J. Kagan, G. Cushon, A. Banner, and T. DeMeo. 2005. International Vegetation Classification of the Pacific Northwest: International correlation of temperate coastal forest plant associations of Oregon, Washington, British Columbia and Alaska. Contributors: B.C. Ministry of Forests, USDA Forest Service, B.C. Conservation Data Centre, Alaska Natural Heritage Program, Washington Natural Heritage Program, and Oregon Natural Heritage Information Center.
- Reid, M. S., L. S. Engelking, and P. S. Bourgeron. 1994. Rare plant communities of the conterminous United States, Western Region. Pages 305-620 in: D. H. Grossman, K. L. Goodin, and C. L. Reuss, editors. Rare plant communities of the conterminous United States, an initial survey. The Nature Conservancy, Arlington, VA.
- Rocchio, F. J., R. C. Crawford, and C. C. Thompson. 2012. San Juan Island National Historical Park vegetation classification and mapping project. Natural Resource Report NPS/NCCN/NRR--2012/603. National Park Service, Fort Collins, CO. 188 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.