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CEGL000491 Tsuga heterophylla / Athyrium filix-femina Forest
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Western Hemlock / Common Ladyfern Forest
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This association occurs in northern Idaho, on the west slope of the Bitterroot Mountains, in the Coeur d''Alene National Forest, and western Montana in Glacier National Park. It occurs on stream terraces, toeslopes and lower slope positions, from roughly 915 to 2500 m (3000-8200 feet) elevation. Slopes are less than 25% and aspects are northwestern to eastern. Soils are well-drained, loamy sands to silt loams in texture, with some having a high gravel content. This is a needle-leaved evergreen forest, dominated by Tsuga heterophylla. Other trees occasionally present may include Thuja plicata, Abies grandis, Pinus monticola, Abies lasiocarpa, and Picea engelmannii, but only Tsuga heterophylla is reproducing successfully. Scattered shrubs occur, but none are particularly abundant. Shrub species occasionally present include Taxus brevifolia, Menziesia ferruginea, Acer glabrum, and Rubus parviflorus. The herbaceous layer is abundant and dominated by perennial ferns. Athyrium filix-femina is always present, with cover usually over 10% and occasionally over 50%. Gymnocarpium dryopteris is also common.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: In terms of composition, abiotic parameters and geographic range ~Tsuga heterophylla / Athyrium filix-femina Forest (CEGL000491)$$ and ~Thuja plicata / Athyrium filix-femina Forest (CEGL000473)$$ are virtually identical. The difference between Tsuga and Thuja dominance of the upper canopy is quite probably related to historical accident, past disturbance events and subsequent successional patterns. Despite the very long fire-return intervals (200-500 years for stand-replacing fire), the longevity of both species, especially Thuja, argues for considering the dual designation (Thuja plicata - Tsuga heterophylla) as appropriate (i.e., combining these two associations into one); if one or the other species responds to disturbance by attaining canopy dominance it is unlikely the non-dominant species will become dominant in the average fire-free interval. Others have recognized that quite probably a dominance continuum exists between these two species by naming at least 8 plant associations with the dual designation (Tsuga heterophylla - Thuja plicata /_).
Arguing against this approach is the approach being taken by the USNVC placing emphasis on existing vegetation composition, and it is indisputable that either climax tree species can be strongly dominant with the other species occurring only in the reproductive layers, if at all. In northern Idaho, where these species are sympatric over an extensive range, there are drainages where one or the other species is present and its complement is not (Daubenmire and Daubenmire 1968); this phenomenon has never been satisfactorily explained and again argues for recognizing separate Thuja plicata and Tsuga heterophylla types.
Arguing against this approach is the approach being taken by the USNVC placing emphasis on existing vegetation composition, and it is indisputable that either climax tree species can be strongly dominant with the other species occurring only in the reproductive layers, if at all. In northern Idaho, where these species are sympatric over an extensive range, there are drainages where one or the other species is present and its complement is not (Daubenmire and Daubenmire 1968); this phenomenon has never been satisfactorily explained and again argues for recognizing separate Thuja plicata and Tsuga heterophylla types.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: This association is a needle-leaved evergreen forest dominated by Tsuga heterophylla. Other trees occasionally present may include Thuja plicata, Abies grandis, Pinus monticola, Abies lasiocarpa, and Picea engelmannii, but only Tsuga heterophylla is reproducing successfully. Scattered shrubs occur, but none are particularly abundant. Species occasionally present include the needle-leaved evergreen Taxus brevifolia and the deciduous broad-leaved Menziesia ferruginea, Acer glabrum, and Rubus parviflorus. The herbaceous layer is abundant and dominated by perennial ferns. Athyrium filix-femina is always present, with cover usually over 10% and occasionally over 50%. Gymnocarpium dryopteris is also common.
Dynamics: No Data Available
Environmental Description: This association occurs in a mountainous region of inland maritime climate, characterized by mild, moderate winters with prolonged gentle rains, deep snow accumulations at higher altitudes and abundant clouds, fog and high humidity. Summers are typically very dry for most of the region (<1 inch precipitation/month). Geologically, the region is underlain by metamorphosed, Precambrian sedimentary strata that have been folded and intensely faulted. This association occupies stream terraces, toeslopes and lower slope positions, from roughly 915 to 2500 m (3000-8200 feet) elevation. Slopes are less than 25% and aspects are northwestern to eastern. Soils are well-drained, loamy sands to silt loams in texture, with a high gravel content. Litter depth averages 5 cm.
Geographic Range: It has been described from northern Idaho, on the west slope of the Bitterroot Mountains, in the Coeur d''Alene National Forest, and west of the Continental Divide (Lake McDonald drainage) in Montana''s Glacier National Park.
Nations: US
States/Provinces: ID, MT, WA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.683943
Confidence Level: Moderate
Confidence Level Comments: No Data Available
Grank: G2Q
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.Nb Rocky Mountain Forest & Woodland Division | D194 | 1.B.2.Nb |
| Macrogroup | 1.B.2.Nb.3 Western Hemlock - Grand Fir - Western Larch Mesic Lower Montane Forest Macrogroup | M500 | 1.B.2.Nb.3 |
| Group | 1.B.2.Nb.3.b Western Red-cedar - Western Hemlock Central Rocky Mountain Forest Group | G217 | 1.B.2.Nb.3.b |
| Alliance | A3613 Western Hemlock - Western Red-cedar Warm-Mesic Central Rocky Mountain Forest & Woodland Alliance | A3613 | 1.B.2.Nb.3.b |
| Association | CEGL000491 Western Hemlock / Common Ladyfern Forest | CEGL000491 | 1.B.2.Nb.3.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: >< Thuja plicata / Athyrium filix-femina Habitat Type (Cooper et al. 1987) [Tsuga heterophylla-dominated stands of this association.]
= Tsuga heterophylla / Athyrium filix-femina (Topik et al. 1986)
= Tsuga heterophylla / Athyrium filix-femina (Topik et al. 1986)
- 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.
- Cooper, S. V., K. E. Neiman, R. Steele, and D. W. Roberts. 1987. Forest habitat types of northern Idaho: A second approximation. General Technical Report INT-236.USDA Forest Service, Intermountain Research Station, Ogden, UT. 135 pp. [reprinted in 1991]
- Daubenmire, R. F., and J. B. Daubenmire. 1968. Forest vegetation of eastern Washington and northern Idaho. Washington State University Agricultural Experiment Station Technical Bulletin No. 60. 104 pp.
- Hop, K., M. Reid, J. Dieck, S. Lubinski, and S. Cooper. 2007. U.S. Geological Survey-National Park Service Vegetation Mapping Program: Waterton-Glacier International Peace Park. U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, WI. 131 pp. plus Appendices A-L.
- Moseley, R. K., and C. A. Wellner. 1988. Establishment record for Upper Shoshone Creek Research Natural Area within Coeur d''Alene National Forest, Shoshone County, Idaho. Unpublished report prepared for Idaho Panhandle National Forests, Coeur d''Alene, ID, by The Nature Conservancy, Moscow, ID. 23 pp. plus maps.
- Reid, M. S., S. V. Cooper, and G. Kittel. 2004. Vegetation classification of Waterton-Glacier International Peace Park. Final report for USGS-NPS Vegetation Mapping Program, International Peace Park Mapping Project. NatureServe, Arlington VA.
- Topik, C., N. M. Halverson, and D. G. Brockway. 1986. Plant associations and management guide for the western hemlock zone. R6-ECOL-230a-1986. USDA Forest Service, Gifford Pinchot National Forest, Pacific Northwest Region, Portland, OR. 137 pp.
- Wellner, C. A. 1985. Establishment record for Montford Creek Research Natural Area within Coeur d''Alene National Forest, Kootenai County, Idaho. Unpublished report prepared for Idaho Panhandle National Forests, Coeur d''Alene, Idaho by The Nature Conservancy, Moscow, ID. 17 pp. plus maps.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.