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CEGL000045 Chamaecyparis lawsoniana - Tsuga heterophylla / Gaultheria shallon - Rhododendron macrophyllum Forest
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Port Orford-cedar - Western Hemlock / Salal - Pacific Rhododendron Forest
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This conifer forest association is found on mesic sites between 450-700 m elevation on sedimentary substrates in southwestern Oregon. Substrates are derived from sedimentary parent materials. Canopy cover averages 84% and is dominated by Chamaecyparis lawsoniana and Pseudotsuga menziesii with a significant component of Tsuga heterophylla. These trees are the only ones that occur with consistency in this association. Occasional individuals of Abies grandis are also present. Immature conifer cover averages 33%, while seedlings and saplings have the lowest density of any Chamaecyparis lawsoniana association. The shrub layer is very well-developed with 93% cover with Gaultheria shallon and Rhododendron macrophyllum dominating. Other shrubs which show maximal development are Mahonia nervosa, Vaccinium ovatum, Mahonia aquifolium, Corylus cornuta, and Acer circinatum. The herbaceous layer is poorly developed, though Polystichum munitum does maintain fairly high cover values.
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: This is a structurally diverse forest association, with the tree canopy dominated by evergreen needle-leaved species and the shrub layers dominated by broad-leaved evergreen species. Chamaecyparis lawsoniana and Pseudotsuga menziesii are the most abundant trees (with 52% and 38% average cover, respectively), and Tsuga heterophylla averages 14% in cover. Several other conifers can be abundant in some stands. The shrub layers are dense, with cover typically well over 75%. Rhododendron macrophyllum is the most abundant shrub (32% cover) and typically is over 2 m tall. The shorter Gaultheria shallon averages 29% cover. Other shrubs commonly present include Mahonia nervosa (= var. nervosa), Vaccinium ovatum, and the deciduous Acer circinatum. The herbaceous layer is poorly developed (17% cover) and strongly dominated by the perennial fern Polystichum munitum, with 14% average cover. Many perennial forb species are found in trace amounts, but no graminoids occur. Mosses average 40% cover.
Dynamics: No Data Available
Environmental Description: This association occurs in a mountainous region (Klamath Mountains Province) of rugged, deeply dissected terrain. Geologically, the province is very complex and of very old deposits. Rock types include volcanic tuffs and sedimentary rocks which have been metamorphosed into schists, gneisses, marbles, and other metavolcanic and metasedimentary rocks. Sandstones, siltstones and shales have been deposited near the coast. The most notable rock types are granitics and elongated, stringer-like outcrops of serpentine. Elevations of this region vary from sea level to over 1525 m (0-5000 feet). This association generally occupies variable aspects on gentle to somewhat steep slopes, from 650 to 750 m (2130-2460 feet) elevation. Parent materials are sedimentary. Soils are moderately deep and well-drained, with an average depth to the C horizon of 73 cm. At least four horizons are present of varying colors, textures, or structures. Textures throughout are silty loams, with some clays. The surface horizons are typically gravelly and become increasingly gravelly, as well as cobbly, with depth.
The climate of the region is maritime, with wet, mild winters, cool, relatively dry summers at higher elevations and warm to hot summers at lower elevations, prolonged cloudy periods, and high annual precipitation. Precipitation varies from over 178 cm (70 inches) annually near the coast, to less than 76 cm (30 inches) annually on the eastern slope, where a rainshadow effect is pronounced and summers are very dry.
The climate of the region is maritime, with wet, mild winters, cool, relatively dry summers at higher elevations and warm to hot summers at lower elevations, prolonged cloudy periods, and high annual precipitation. Precipitation varies from over 178 cm (70 inches) annually near the coast, to less than 76 cm (30 inches) annually on the eastern slope, where a rainshadow effect is pronounced and summers are very dry.
Geographic Range: One of the primary dominant species, Port Orford-cedar, is very local, restricted to southwestern Oregon and northwestern California. This association is even more local, found only in the coastal strip in southern Coos and northern Curry County, Oregon.
Nations: US
States/Provinces: OR
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.683385
Confidence Level: Low
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.a Redwood Forest Group | G235 | 1.B.2.Nd.3.a |
| Alliance | A0104 Port Orford-cedar Forest Alliance | A0104 | 1.B.2.Nd.3.a |
| Association | CEGL000045 Port Orford-cedar - Western Hemlock / Salal - Pacific Rhododendron Forest | CEGL000045 | 1.B.2.Nd.3.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Chamaecyparis lawsoniana - Tsuga heterophylla / Rhododendron macrophyllum - Gaultheria shallon (Atzet et al. 1996)
= Chamaecyparis lawsoniana - Tsuga heterophylla / Rhododendron macrophyllum - Gaultheria shallon (Hawk 1977)
= Chamaecyparis lawsoniana - Tsuga heterophylla / Rhododendron macrophyllum - Gaultheria shallon (Hawk 1977)
- Atzet, T. A., D. E. White, L. A. McCrimmon, P. A. Martinez, P. R. Fong, and V. D. Randall. 1996. Field guide to the forested plant associations of southwestern Oregon. Technical Paper R6-NR-ECOL-TP-17-96. USDA Forest Service, Pacific Northwest Region, Portland, OR.
- 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.
- 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.
- Hawk, G. M. 1977. A comparative study of temperate Chamaecyparis forests. Unpublished dissertation, Oregon State University, Corvallis. 194 pp.
- 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.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.