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CEGL000041 Abies lowiana - Chamaecyparis lawsoniana - Pseudotsuga menziesii / (Mahonia nervosa) / Achlys triphylla Forest
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: Sierra White Fir - Port Orford-cedar - Douglas-fir / (Cascade Barberry) / Sweet After Death Forest
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This giant coniferous forest association is codominated by Abies lowiana, Chamaecyparis lawsoniana, and Pseudotsuga menziesii. Stands are found on valley bottoms and along stream courses in southwestern Oregon and adjacent northern California. Average elevation is 1280 m. These forests are usually found on moist, moderately developed, well-drained colluvial soils with the coarsest texture of any Chamaecyparis lawsoniana association. These soils are usually derived from metavolcanics or granitics which limits their fertility and water holding capacity. For these reasons canopy closure averages only 75%. The canopy is dominated by Abies lowiana (5% cover),Chamaecyparis lawsoniana (17% cover), and Pseudotsuga menziesii (45% cover), with some individuals of Abies magnifica, Taxus brevifolia, Picea breweriana, and/or Callitropsis nootkatensis sometimes present. The shrub stratum averages 38% cover, but can be quite variable. Younger stands tend to be dense while mature stands have diffuse shrub layers only in major canopy openings. Mahonia nervosa is present in all stands, but only attains an average of 3-5% cover. The herbaceous layer tends to be species rich, attaining its maximum cover in mature stands. Achlys triphylla has a mean cover value of 11%, while up to 16 other species of herb may also be present. These forests are very old - usually around 400 years of age. Mistletoe can be a problem with the Pseudotsuga menziesii, and the Chamaecyparis lawsoniana is gravely threatened by Phytophthora, an introduced root pathogen. The clear dominance of Achlys triphylla in the herb layer differentiates this association from other Chamaecyparis lawsoniana associations.
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 association is both structurally and compositionally variable. The tree canopy, usually over 50 m in height, is dominated by a mix of the evergreen needle-leaved Chamaecyparis lawsoniana, Pseudotsuga menziesii, and Abies lowiana (= Abies concolor var. lowiana). Any one of these three species can be the most abundant in a particular stand, but total canopy cover is typically 70% or higher. Several other conifers can be present, including Abies magnifica, Picea breweriana, and Callitropsis nootkatensis (= Chamaecyparis nootkatensis). A lower canopy layer is present, dominated by a mix of conifer regeneration and broad-leaved evergreen species. Conifers important in this layer include Chamaecyparis lawsoniana, Abies lowiana, Taxus brevifolia, and in some stands Calocedrus decurrens. Broad-leaved species can include Notholithocarpus densiflorus (= Lithocarpus densiflorus) and Chrysolepis chrysophylla (= Castanopsis chrysophylla). The shrub layers are very diverse and variable, with cover ranging from 13% to over 35%. Species include both evergreen and deciduous, tall and short, broad-leaved shrubs, with a pattern of occasional local dominance. The low, evergreen Mahonia nervosa has the highest constancy, occurring in nearly all stands and in some quite abundant. Some of the tall-shrub species include Rhododendron occidentale, Quercus sadleriana, and Quercus vacciniifolia, while short species include Whipplea modesta, Rubus ursinus, Chimaphila umbellata, Rosa gymnocarpa, Paxistima myrsinites, and Vaccinium membranaceum. The herbaceous layer is very diverse and abundant; most species are perennial forbs. Achlys triphylla is always present and often has cover over 10%. Some of the more constant species include Adenocaulon bicolor, Clintonia uniflora, Prosartes hookeri (= Disporum hookeri), Goodyera oblongifolia, Linnaea borealis, Tiarella trifoliata, Trientalis borealis ssp. latifolia, and Trillium ovatum. Cover of mosses is low, usually less than 5%.
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 1520 m.
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 150 cm annually near the coast, to less than 75 cm annually on the eastern slope, where a rainshadow effect is pronounced and summers are very dry.
This association occurs in scattered localities throughout most of the range of Chamaecyparis lawsoniana, particularly in the eastern and southern areas. It is found from 900-1540 m elevation, predominantly on slopes of northerly and westerly aspects. Sites include concave midslopes or valley bottoms, and slope percents vary greatly, from flat to steep (range from 0-60%). Soils are derived from a variety of parent materials, but a large proportion of stands occur on ultramafic colluvium and alluvium. Other parent materials are colluvium of granitics, schists, and metavolcanics. Soil textures are variable, from sandy loams to clay loams, but all horizons have high proportions of gravels and cobbles. Typical depth to the surface of the C horizon ranges from 45-60 cm, and most soils are moist to wet in all horizons, even through much of the summer. Litter covers at least 90% of the ground surface.
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 150 cm annually near the coast, to less than 75 cm annually on the eastern slope, where a rainshadow effect is pronounced and summers are very dry.
This association occurs in scattered localities throughout most of the range of Chamaecyparis lawsoniana, particularly in the eastern and southern areas. It is found from 900-1540 m elevation, predominantly on slopes of northerly and westerly aspects. Sites include concave midslopes or valley bottoms, and slope percents vary greatly, from flat to steep (range from 0-60%). Soils are derived from a variety of parent materials, but a large proportion of stands occur on ultramafic colluvium and alluvium. Other parent materials are colluvium of granitics, schists, and metavolcanics. Soil textures are variable, from sandy loams to clay loams, but all horizons have high proportions of gravels and cobbles. Typical depth to the surface of the C horizon ranges from 45-60 cm, and most soils are moist to wet in all horizons, even through much of the summer. Litter covers at least 90% of the ground surface.
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 on granitic habitats near the California border in Oregon, and in similar sites in extreme northwestern California.
Nations: US
States/Provinces: CA, OR
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.686608
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.2 Incense-cedar - Jeffrey Pine - Sierra White Fir Forest Macrogroup | M023 | 1.B.2.Nd.2 |
| Group | 1.B.2.Nd.2.a Incense-cedar - Sugar Pine - Sierra White Fir Forest & Woodland Group | G344 | 1.B.2.Nd.2.a |
| Alliance | A0156 Brewer Spruce - Sierra White Fir Forest Alliance | A0156 | 1.B.2.Nd.2.a |
| Association | CEGL000041 Sierra White Fir - Port Orford-cedar - Douglas-fir / (Cascade Barberry) / Sweet After Death Forest | CEGL000041 | 1.B.2.Nd.2.a |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: ? Abies - Chamaecyparis lawsoniana / herb (Hawk 1977)
? Abies concolor - Chamaecyparis lawsoniana (Atzet and Wheeler 1984)
? Abies concolor - Chamaecyparis lawsoniana / herb (Hawk 1977)
> Chamaecyparis lawsoniana - Pseudotsuga menziesii association (Odion et al. 2013)
> Chamaecyparis lawsoniana / Alnus rhombifolia association (Odion et al. 2013)
? Chamaecyparis lawsoniana / Berberis nervosa / Achlys triphylla (Atzet and Wheeler 1984)
? Abies concolor - Chamaecyparis lawsoniana (Atzet and Wheeler 1984)
? Abies concolor - Chamaecyparis lawsoniana / herb (Hawk 1977)
> Chamaecyparis lawsoniana - Pseudotsuga menziesii association (Odion et al. 2013)
> Chamaecyparis lawsoniana / Alnus rhombifolia association (Odion et al. 2013)
? Chamaecyparis lawsoniana / Berberis nervosa / Achlys triphylla (Atzet and Wheeler 1984)
- 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.
- Atzet, T., and D. L. Wheeler. 1984. Preliminary plant associations of the Siskiyou Mountains Province, Siskiyou National Forest. 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.
- Hawk, G. M. 1977. A comparative study of temperate Chamaecyparis forests. Unpublished dissertation, Oregon State University, Corvallis. 194 pp.
- Jimerson, T. J. 1994. A field guide to the Port Orford cedar plant associations in northwestern California. Pacific Southwest Research Station PSW-R5-ECOL-TP-OO2. Six Rivers National Forest, Eureka, CA. 109 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.
- Odion, D. C., D. A. DiPaolo, L. C. Groshong, D. A. Sarr, and S. Mohren. 2013. Vegetation Inventory Project: Oregon Caves National Monument and proposed expansion area. Natural Resource Technical Report NPS/ORCA/NRTR--2013/782. National Park Service, Fort Collins, CO. 272 pp.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.