Print Report
CEGL000632 Alnus rhombifolia / Betula occidentalis Riparian Forest
Type Concept Sentence: No Data Available
Common (Translated Scientific) Name: White Alder / Water Birch Riparian Forest
Colloquial Name: No Data Available
Hierarchy Level: Association
Type Concept: This plant association is described from data collected in the Snake and Salmon river corridors, within the Blue Mountains ecoregional section. The plant association occurs within a relatively discrete elevational band (350-640 m [1150-2100 feet] and 550-760 m [1800-2500 feet], respectively) in the deeply incised terrain of the Snake and Salmon canyons. The association occurs on stable and unstable stream channel substrates. In this region of west-central Idaho, Betula occidentalis is usually found at elevations higher than Alnus rhombifolia. These species do co-occur near the upper elevational limit of Alnus rhombifolia on tributaries with fair to good stream channel stability ratings. This implies that Betula occidentalis occupies sites with less frequent disturbance, and with cold air drainage from higher elevations. This forest plant association is dominated by broad-leaved, deciduous tree species. Alnus rhombifolia is codominant with Betula occidentalis, both occur with high cover. Populus balsamifera ssp. trichocarpa, Abies grandis and Pseudotsuga menziesii may also be associated. The understory is characterized by a dense, multi-layered, and species-rich deciduous shrub layer. Species commonly present include Crataegus douglasii, Cornus sericea, Ribes oxyacanthoides ssp. irriguum, Rosa woodsii, Rhus glabra, Philadelphus lewisii, Prunus virginiana, Sambucus nigra ssp. cerulea, and Salix scouleriana. The herbaceous component of this plant association has not been described.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: This association is defined as a PNV vegetation type.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available
Floristics: This forest association is dominated by broad-leaved deciduous woody species. The tree Alnus rhombifolia is codominant with the typically shorter tree Betula occidentalis, both with high cover. Other occasional trees can include Populus balsamifera ssp. trichocarpa (= Populus trichocarpa), and the conifers Abies grandis and Pseudotsuga menziesii. There is a dense, multi-layered, and diverse shrub layer, also primarily deciduous. Species commonly present include Crataegus douglasii, Cornus sericea, Ribes oxyacanthoides ssp. irriguum (= Ribes irriguum), Rosa woodsii, Rhus glabra, Philadelphus lewisii, Prunus virginiana, Sambucus nigra ssp. cerulea (= Sambucus caerulea), and Salix scouleriana. The herbaceous component of this association is undescribed. The small evergreen needle-leaved tree Taxus brevifolia is found in stands of this association along the Salmon River tributaries.
Dynamics: No Data Available
Environmental Description: This association is found in a mountainous region dissected by major river canyons and tributary streams. There are elevational extremes in this region, from subalpine summits over 2740 m (9000 feet), to canyon bottoms below 610 m (2000 feet). Topography is characterized by precipitous canyon walls along the rivers, steep upland slopes, and smaller tributary streams with cliffs, rocky slopes and mass-wasting features such as slumps and mud-rock flows. The soils of the region are especially prone to erosion and slippage. Slopes often exceed the angle of repose and periodic severe thunderstorms with intense rains will supersaturate the soil mantle. The resulting slumping and mud-rock flows often deposit materials into stream channels and can destroy streambanks.
The climatic conditions in these deep canyon bottoms are strikingly different from surrounding uplands and mountains. In the canyons, summers are hot and dry, and winters mild, with only limited and ephemeral snows. Precipitation is variable, but generally the higher elevation reaches have higher precipitation. Annual precipitation is approximately 33 cm (13 inches) at 225 m (740 feet), and about 46 cm (18 inches) at 610 m (2000 feet). However, a rainshadow effect occurs farther to the east, in upstream reaches, and annual precipitation is less than 25 m (10 inches).
This association occurs on riparian sites in canyon bottoms, from 350 to 640 m (1150-2100 feet) elevation along the Snake River tributaries, and from 550 to 760 m (1800-2500 feet) along the Salmon River tributaries. In this region of west-central Idaho, Betula occidentalis is usually found at elevations higher than Alnus rhombifolia. These species do co-occur near the upper elevational limit of white alder on tributaries with fair to good stream channel stability ratings. This implies that river birch occupies sites with less frequent disturbance, and with cold-air drainage from higher elevations.
The climatic conditions in these deep canyon bottoms are strikingly different from surrounding uplands and mountains. In the canyons, summers are hot and dry, and winters mild, with only limited and ephemeral snows. Precipitation is variable, but generally the higher elevation reaches have higher precipitation. Annual precipitation is approximately 33 cm (13 inches) at 225 m (740 feet), and about 46 cm (18 inches) at 610 m (2000 feet). However, a rainshadow effect occurs farther to the east, in upstream reaches, and annual precipitation is less than 25 m (10 inches).
This association occurs on riparian sites in canyon bottoms, from 350 to 640 m (1150-2100 feet) elevation along the Snake River tributaries, and from 550 to 760 m (1800-2500 feet) along the Salmon River tributaries. In this region of west-central Idaho, Betula occidentalis is usually found at elevations higher than Alnus rhombifolia. These species do co-occur near the upper elevational limit of white alder on tributaries with fair to good stream channel stability ratings. This implies that river birch occupies sites with less frequent disturbance, and with cold-air drainage from higher elevations.
Geographic Range: Miller (1976) described the association as occurring on the Snake and Salmon rivers and their tributaries.
Nations: US
States/Provinces: ID, OR, WA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.686031
Confidence Level: Low - Poorly Documented
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.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.b Mountain Hemlock - Fir species / Willow species Montane Riparian Woodland Group | G507 | 1.B.3.Ng.1.b |
| Alliance | A0306 White Alder Cascadian Riparian Woodland Alliance | A0306 | 1.B.3.Ng.1.b |
| Association | CEGL000632 White Alder / Water Birch Riparian Forest | CEGL000632 | 1.B.3.Ng.1.b |
Concept Lineage: No Data Available
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Alnus rhombifolia / Betula occidentalis Temporarily Flooded Forest (Crawford 2003)
= Alnus rhombifolia / Betula occidentalis Association (Crowe et al. 2004)
= Alnus rhombifolia Forest Alliance (Daubenmire 1970) [(p.60)]
= Alnus rhombifolia / Betula occidentalis Association (Crowe et al. 2004)
= Alnus rhombifolia Forest Alliance (Daubenmire 1970) [(p.60)]
- 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.
- Crawford, R. C. 2001. Initial riparian and wetland classification and characterization of the Columbia Basin in Washington. Prepared for Environmental Protection Agency and Bureau of Land Management, Spokane District. Washington Natural Heritage Program, Washington Department of Natural Resources, Olympia. 83 pp.
- Crawford, R. C. 2003. Riparian vegetation classification of the Columbia Basin, Washington. Natural Heritage Report 2003-03. Washington Natural Heritage Program, Washington Department of Natural Resources, Olympia. 98 pp. plus appendices.
- Crowe, E. A., B. L. Kovalchik, and M. J. Kerr. 2004. Riparian and wetland vegetation of central and eastern Oregon. Oregon Natural Heritage Information Center, Institute for Natural Resources, Oregon State University, Portland. 473 pp. [http://oregonstate.edu/ornhic/ publications.html]
- Daubenmire, R. F. 1970. Steppe vegetation of Washington. Washington State University Agricultural Experiment Station Technical Bulletin No. 62. 131 pp.
- Holmstead, G. 2001. Vegetation of the Snake River corridor in Hells Canyon-Weiser, Idaho to the Salmon River. Technical Report Appendix E.3.3-1 prepared for FERC License No. 1971, Hells Canyon Complex by Idaho Power Company, Boise, ID. 49 pp. plus appendices.
- IDCDC [Idaho Conservation Data Center]. 2005. Wetland and riparian plant associations in Idaho. Idaho Conservation Data Center, Idaho Department of Fish and Game, Boise. [http://fishandgame.idaho.gov/tech/CDC/ecology/wetland_riparian_assoc.cfm] (accessed 14 June 2005).
- 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.
- Mancuso, M., and R. Moseley. 1994. Vegetation description, rare plant inventory, and vegetation monitoring for Craig Mountain, Idaho. Unpublished report prepared for Bonneville Power Administration. 146 pp.
- Miller, J. R., Jr., and D. K. Halligan. 1976. Some aspects of the snow damage to the Black Hills Forest. 26-27 April 1976. Unpublished report.
- Miller, T. B. 1976. Ecology of riparian communities dominated by white alder in western Idaho. Unpublished thesis, University of Idaho, Moscow. 154 pp.
- Neiman, K. 1987. Inventory of Garden Creek Ranch conducted during summer of 1987. Report to The Nature Conservancy, Sun Valley, Idaho.
- WNHP [Washington Natural Heritage Program]. 2018. Unpublished data files. Washington Natural Heritage Program, Department of Natural Resources, Olympia, WA.
- Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.