Print Report
A3777 Alnus rhombifolia Riparian Forest Alliance
Type Concept Sentence: These riparian woodlands and forests are dominated by Alnus rhombifolia and/or Alnus rubra and are found nearly throughout California along riparian corridors of coastal mountains, inland foothill and lower montane zones often as narrow strips along perennial streams.
Common (Translated Scientific) Name: White Alder Riparian Forest Alliance
Colloquial Name: White Alder Riparian Forest
Hierarchy Level: Alliance
Type Concept: These are riparian woodlands and forests dominated by Alnus rhombifolia and/or Alnus rubra. Codominant trees may include Acer macrophyllum, Chamaecyparis lawsoniana, Fraxinus latifolia, Notholithocarpus densiflorus, Platanus racemosa, Populus fremontii, Populus balsamifera ssp. trichocarpa, Pseudotsuga menziesii, Quercus lobata, and Salix species. They are found throughout California along riparian corridors, incised canyons, seeps and streambanks, channel bars, floodplains and terraces. Elevations range from sea level to 2500 m. Stands occur primarily in coastal areas and inland foothill and lower montane zones often as narrow strips along perennial streams. Climate is Mediterranean, with most of the 70-165 cm of precipitation coming in winter and spring, and little or none during the summer.
Diagnostic Characteristics: Riparian or floodplain woodlands and forests dominated by Alnus rhombifolia and/or Alnus rubra.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This represents Alnus rhombifolia and Alnus rubra riparian stands throughout California cismontane. The occurrences of Alnus rhombifolia along the Columbia River in eastern Oregon and western Idaho belong to ~North Pacific Montane Riparian Woodland Group (G507)$$. Some reviews suggest the Alnus rubra associations be included in a North Pacific group; however, they are included here as these associations have Mediterranean Californian composition in the understory and occur from the Klamath Mountains south into San Luis Obispo County, and seem to fit this group better than a North Pacific group.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: The tree layer is dominated by broad-leaved deciduous trees. The canopy consists of trees with overlapping crowns, generally forming 60-100% cover. Shrub and forb layers are usually present.
Floristics: Vegetation stands within this alliance are classified as riparian-wetland cold-deciduous forests. The dominant trees are Alnus rhombifolia and/or Alnus rubra, and are found growing with several codominants and a variety of understory species. Tree canopy cover is usually high, often with a dense, multi-layered and diverse shrub layer, also primarily deciduous. In some cases, both the tree and shrub canopies can be sparse, but Alnus rhombifolia or Alnus rubra is always a dominant. Codominant trees may include Acer macrophyllum, Chamaecyparis lawsoniana, Fraxinus latifolia, Notholithocarpus densiflorus (= Lithocarpus densiflorus), Platanus racemosa, Populus fremontii, Populus balsamifera ssp. trichocarpa (= Populus trichocarpa), Pseudotsuga menziesii, Quercus lobata, and Salix species. The herbaceous layer is often sparse because of the dense canopy or frequent disturbance. Stands can be solely dominated by Alnus rhombifolia or include other codominants such as Abies grandis, Acer macrophyllum, Chamaecyparis lawsoniana, Fraxinus latifolia, Platanus racemosa, Populus fremontii, Populus balsamifera ssp. trichocarpa (= Populus trichocarpa), Pseudotsuga menziesii, Quercus chrysolepis, and Taxus brevifolia. The shrub canopy can be diverse and dense with species such as Acer circinatum, Cornus sericea, Corylus cornuta var. californica, Crataegus douglasii, Rhododendron occidentale, and/or Salix commutata. The herbaceous layer, when present, may include Carex amplifolia or Torreyochloa pallida var. pauciflora (= Torreyochloa pauciflora).
Dynamics: Alnus rhombifolia and Alnus rubra appear well-adapted to colonize riparian sites disturbed by periodic flooding, mud and rock flows.
Environmental Description: This alliance is found from foothills and montane riparian sites in the Cascade Range and Klamath Mountains in the northern part of California, montane riparian sites in the Transverse and Peninsular ranges in the southern part of the state, and in the northern and central coastal mountains. Elevations range from 600 to 1900 m. Climate is Mediterranean, with most of the 70-165 cm of precipitation coming in winter and spring, and little or none during the summer.
Geographic Range: This alliance is found in California riparian zones from the foothills and montane Klamath Mountains and Cascade Range in the north, to montane Transverse and Peninsular ranges of southern California, as well as northern and central Coast Ranges. It likely occurs south into Baja California, Mexico.
Nations: MX?,US
States/Provinces: CA, MXBCN?, OR?, WA?
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899829
Confidence Level: Moderate
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.3 Temperate Flooded & Swamp Forest Formation | F026 | 1.B.3 |
| Division | 1.B.3.Ng Vancouverian Flooded & Swamp Forest Division | D193 | 1.B.3.Ng |
| Macrogroup | 1.B.3.Ng.1 Vancouverian Flooded & Swamp Forest Macrogroup | M035 | 1.B.3.Ng.1 |
| Group | 1.B.3.Ng.1.d Sitka Spruce - Black Cottonwood - Oregon Ash Lowland Riparian Forest Group | G851 | 1.B.3.Ng.1.d |
| Alliance | A3777 White Alder Riparian Forest Alliance | A3777 | 1.B.3.Ng.1.d |
| Association | CEGL003163 Red Alder / Arroyo Willow Riparian Forest | CEGL003163 | 1.B.3.Ng.1.d |
| Association | CEGL003463 Red Alder / Salmonberry - Red Elderberry Riparian Forest | CEGL003463 | 1.B.3.Ng.1.d |
| Association | CEGL008693 White Alder / Sierran Riparian Forest | CEGL008693 | 1.B.3.Ng.1.d |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: > Alnus rhombifolia (White alder groves) Alliance (Sawyer et al. 2009) [61.420.00]
= Alnus rhombifolia Alliance (White alder groves) (Buck-Diaz et al. 2012)
>< Alnus rubra (Red alder forest) Alliance (Sawyer et al. 2009) [61.410.00]
= Alnus rhombifolia Alliance (White alder groves) (Buck-Diaz et al. 2012)
>< Alnus rubra (Red alder forest) Alliance (Sawyer et al. 2009) [61.410.00]
- Barbour, M. G., and J. Major, editors. 1977. Terrestrial vegetation of California. John Wiley and Sons, New York. 1002 pp.
- Buck-Diaz, J., S. Batiuk, and J. M. Evens. 2012. Vegetation alliances and associations of the Great Valley ecoregion, California. California Native Society, Sacramento, CA. [http://cnps.org/cnps/vegetation/pdf/great_valley_eco-vegclass2012.pdf]
- 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.
- Johnson, F. D. 1968. Taxonomy and distribution of northwestern alders. Pages 9-22 in: J. M. Trappe, J. F. Franklin, R. F. Tarrant, and G. M. Hansen, editors. Biology of Alder. Pacific Northwest Forest and Range Experimental Station, Portland, OR.
- 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.
- 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.
- Sawyer, J. O., and T. Keeler-Wolf. 1995. A manual of California vegetation. California Native Plant Society, Sacramento. 471 pp.