Print Report
A0427 Alnus rubra - Acer macrophyllum - Pseudotsuga menziesii Forest Alliance
Type Concept Sentence: This forest alliance contains forested stands with an overstory canopy of Acer macrophyllum and/or Alnus rubra, with at least significant conifer cover by Abies grandis, Picea sitchensis, Pseudotsuga menziesii, or Tsuga heterophylla emergent through the deciduous layer. This alliance occurs along the Pacific Coast and in coastal valleys from northern British Columbia to northern California (where it would be restricted to the immediate coastal areas). This maritime-influenced region has mild winter temperatures and receives 75-400 cm of annual precipitation, falling mostly as winter rain. Vegetation usually occurs along low-elevation (0-1000 m) valley bottoms and adjacent lower toeslopes, often forming a seral community in moist coniferous forests.
Common (Translated Scientific) Name: Red Alder - Bigleaf Maple - Douglas-fir Forest Alliance
Colloquial Name: Red Alder - Bigleaf Maple - Douglas-fir Forest
Hierarchy Level: Alliance
Type Concept: This forest alliance consists of forests where Acer macrophyllum and/or Alnus rubra are dominant with at least half as much cover by conifer species such as Abies grandis, Picea sitchensis, Pseudotsuga menziesii, or Tsuga heterophylla emergent through the deciduous layer. The forest understory is usually species-rich and well-developed. Common shrub species include Acer circinatum, Corylus cornuta var. californica, Menziesia ferruginea, Rhododendron macrophyllum, Rubus spectabilis, Sambucus racemosa var. melanocarpa, Symphoricarpos albus, and Vaccinium parvifolium. The herbaceous layer is usually well-developed and can be very diverse, with Asarum caudatum, Hydrophyllum tenuipes, Oxalis oregana, Polystichum munitum, and Trillium ovatum particularly common. It occurs along the Pacific Coast and in coastal valleys from northern British Columbia to northern California (where it would be restricted to the immediate coastal areas). This maritime-influenced region has mild winter temperatures and receives 75-400 cm of annual precipitation, falling mostly as winter rain. Vegetation usually occurs along low-elevation (0-1000 m) valley bottoms and adjacent lower toeslopes, often forming a seral community in moist coniferous forests.
Diagnostic Characteristics: Alnus rubra- and/or Acer macrophyllum-dominated stands with conifer component at least 25% relative cover but not greater than 50% relative cover.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This is a mixed deciduous-evergreen canopy alliance. There must be 25-50% relative cover of conifer trees in the canopy. Greater than 50% relative cover of conifers usually moves the stand into a conifer-dominated alliance.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: These forests are typically characterized by a broad-leaved cold-deciduous and needle-leaved evergreen tree canopy from 35-50 m high with over 60% cover. Often the canopy is two-tiered with the evergreen trees emergent through the deciduous tree layer. A cold-deciduous or evergreen shrub layer is often present, ranging from 20-60% cover. The herbaceous understory is typically composed of a diverse and dense mixture of shade-tolerant forbs and ferns. The conifers may form a subcanopy which is obscured by the deciduous overstory in aerial photographs and remote sensing imagery, or vice versa.
Floristics: This forest alliance consists of forests where Acer macrophyllum and/or Alnus rubra are dominant with at least half as much cover by conifer species such as Abies grandis, Picea sitchensis, Pseudotsuga menziesii, or Tsuga heterophylla emergent through the deciduous layer. In the southern portion of the alliance''s range, or at higher elevations, Abies grandis drops out altogether. Broad-leaved deciduous or evergreen trees, such as Umbellularia californica, Cornus nuttallii, and Betula papyrifera, may also be present in the upper tree stratum, or as a subcanopy. The forest understory is usually species-rich and well-developed. Common shrub species include Acer circinatum, Corylus cornuta var. californica, Menziesia ferruginea, Rhododendron macrophyllum, Rubus spectabilis, Sambucus racemosa var. melanocarpa, Symphoricarpos albus, and Vaccinium parvifolium. The herbaceous layer is usually well-developed and can be very diverse, Asarum caudatum, Hydrophyllum tenuipes, Oxalis oregana, Polystichum munitum, and Trillium ovatum particularly common.
Dynamics: These are primarily second-growth forests, resulting from past logging or historic wildfires within the Douglas-fir, Douglas-fir - western hemlock, Sitka spruce, and western hemlock zones. In the Puget lowlands, these appear to be communities of natural origin. At all except the wettest sites, dominance shifts towards Pseudotsuga menziesii, Tsuga heterophylla, or Picea sitchensis with stand age, forming a two-tiered canopy.
Environmental Description: The vegetation types within this alliance occur along the Pacific Coast in the Cascades foothills and lowlands of the Puget Trough. Vegetation within this alliance usually occurs along low-elevation (0-1000 m) valley bottoms and adjacent lower toeslopes, often forming a seral community in moist coniferous forests. This maritime-influenced region has mild winter temperatures, and receives 75-400 cm of annual precipitation, falling mostly as winter rain.
Geographic Range: This alliance is found from northern British Columbia south to northern California along the coast and interior valleys.
Nations: CA,US
States/Provinces: BC, CA, OR, WA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.898992
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
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.g Red Alder - Bigleaf Maple Rainforest Group | G237 | 1.B.2.Nd.3.g |
| Alliance | A0427 Red Alder - Bigleaf Maple - Douglas-fir Forest Alliance | A0427 | 1.B.2.Nd.3.g |
| Association | CEGL000517 Bigleaf Maple - Douglas-fir / Beaked Hazelnut / Pacific Waterleaf Forest | CEGL000517 | 1.B.2.Nd.3.g |
| Association | CEGL000519 Grand Fir - Bigleaf Maple / Common Snowberry Forest | CEGL000519 | 1.B.2.Nd.3.g |
| Association | CEGL003394 Bigleaf Maple - Douglas-fir / Vine Maple / Western Swordfern Forest | CEGL003394 | 1.B.2.Nd.3.g |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: > Acer macrophyllum (Bigleaf maple forest) Alliance (Sawyer et al. 2009) [61.450.00]
> Alnus rubra (Red alder forest) Alliance (Sawyer et al. 2009) [61.410.00]
>< Red Alder: 221 (Eyre 1980)
> Alnus rubra (Red alder forest) Alliance (Sawyer et al. 2009) [61.410.00]
>< Red Alder: 221 (Eyre 1980)
- Chappell, C., R. Crawford, J. Kagan, and P. J. Doran. 1997. A vegetation, land use, and habitat classification system for the terrestrial and aquatic ecosystems of Oregon and Washington. Unpublished report prepared for Wildlife habitat and species associations within Oregon and Washington landscapes: Building a common understanding for management. Prepared by Washington and Oregon Natural Heritage Programs, Olympia, WA, and Portland, OR. 177 pp.
- Eyre, F. H., editor. 1980. Forest cover types of the United States and Canada. Society of American Foresters, Washington, DC. 148 pp.
- Faber-Langendoen, D., J. Drake, M. Hall, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, M. Russo, K. Schulz, L. Sneddon, K. Snow, and J. Teague. 2013-2019b. Screening alliances for induction into the U.S. National Vegetation Classification: Part 1 - Alliance concept review. NatureServe, Arlington, VA.
- 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.
- Hemstrom, M. A., S. E. Logan, and W. Pavlat. 1987. Plant association and management guide, Willamette National Forest. Report R6-Ecol 257-B-86. USDA Forest Service, Pacific Northwest Region, Portland, OR. 312 pp.
- ORNHP [Oregon Natural Heritage Program]. No date. Unpublished data files. Oregon Natural Heritage Program, The Nature Conservancy, Portland, OR.
- Sawyer, J. O., T. Keeler-Wolf, and J. Evens. 2009. A manual of California vegetation. Second edition. California Native Plant Society, Sacramento CA. 1300 pp.