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A3743 Fraxinus latifolia - Populus balsamifera ssp. trichocarpa - Alnus spp. Riparian Forest Alliance
Type Concept Sentence: This alliance comprises streamside riparian forests dominated by Populus balsamifera ssp. trichocarpa and/or Fraxinus latifolia in the upper canopy. Stands can be composed of pure Populus balsamifera ssp. trichocarpa or Fraxinus latifolia or a mix of the two and may be codominated by other deciduous trees such as Acer macrophyllum and/or Alnus rubra. Populus balsamifera ssp. trichocarpa is always present and characteristic. This alliance is found in coastal lowlands from south-central Alaska to northern California.
Common (Translated Scientific) Name: Oregon Ash - Black Cottonwood - Alder species Riparian Forest Alliance
Colloquial Name: Oregon Ash - Black Cottonwood - Alder Riparian Forest
Hierarchy Level: Alliance
Type Concept: This alliance comprises streamside riparian forests dominated by Populus balsamifera ssp. trichocarpa and/or Fraxinus latifolia in the upper canopy. Stands can be composed of pure Populus balsamifera ssp. trichocarpa or Fraxinus latifolia or a mix of the two and may be codominated by other deciduous trees such as Acer macrophyllum and/or Alnus rubra. Populus balsamifera ssp. trichocarpa is always present and characteristic. This alliance is found in coastal lowlands from south-central Alaska to northern California. Elevation ranges from low to mid elevations (around sea level to 1000 m). Stands occur on active floodplains on well-drained alluvial soils that either experience overbank flooding or high water tables during the snowmelt or rainy seasons. Stands may also occur on higher terraces that are less likely to flood. This alliance may be found along large channels along the Columbia and Willamette rivers, to smaller channels. Stands may be far from an active channel, but are well within the active 100-year floodplain. This alliance does not include isolated hillside springs or seeps.
Diagnostic Characteristics: Upper canopy dominated by deciduous trees; if conifers are present, they constitute <25% relative cover.
Rationale for Nominal Species or Physiognomic Features: No Data Available
Classification Comments: Riparian and floodplain forests dominated by deciduous trees.
Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: These forests have a dense canopy of cold-deciduous trees of moderate stature (10-25 m). Multiple age classes of trees are usually present. Cold-deciduous shrubs are typically abundant and usually form dense thickets. A lush herbaceous layer of perennial graminoids, ferns, and forbs is typical.
Floristics: This alliance is dominated by Fraxinus latifolia and/or Populus balsamifera ssp. trichocarpa and may be codominated by other deciduous trees such as Acer macrophyllum, Alnus rubra, and/or Salix spp. Other species present may include Alnus rhombifolia, Crataegus douglasii, Lonicera involucrata, Quercus garryana, Rosa rubiginosa (= Rosa eglanteria), Rubus ursinus, Spiraea douglasii, Symphoricarpos albus, and Toxicodendron diversilobum. The herbaceous layer is usually a lush layer of perennial graminoids, forbs, and ferns. Species include Agrostis capillaris (= Agrostis tenuis), Athyrium filix-femina, Carex deweyana, Carex obnupta, Carex ovalis (= Carex leporina), Carex unilateralis, Eleocharis acicularis, Elymus glaucus, Galium aparine, Galium trifidum, Geum macrophyllum, Hordeum brachyantherum, Polystichum munitum, Ranunculus uncinatus, Urtica dioica, and Veronica species.
Dynamics: Flooding is typical following winter and spring rain and snowmelt. Scour associated with flooding is common in these communities, resulting in complex soil and disturbance patterns at fine scales. Dominant canopy species in these forests are dependent upon flooding disturbance for reproduction.
Environmental Description: These forest communities occur in low-elevation (0-500 m) wetland habitats, typically in poorly drained swales or riparian areas. They also occupy drier, slightly higher portions of floodplain terraces and natural levees along river channels. Stands are also located on bottomlands that would have been flooded for prolonged periods prior to flood-control dams (Kunze 1994). These are the typical gallery forests of fluvial habitats, such as oxbow lakes and fluvial terraces. Soils are usually silts or clays with poor drainage and occasional gleying, or well-drained sands and gravels with a high water table.
Geographic Range: This alliance is found in coastal lowlands from south-central Alaska to northern California.
Nations: CA,US
States/Provinces: BC, CA, OR, WA
Plot Analysis Summary:
http://vegbank.org/natureserve/ELEMENT_GLOBAL.2.899795
Confidence Level: Low
Confidence Level Comments: No Data Available
Grank: GNR
Greasons: No Data Available
Concept Lineage: A.NCCN-030
Predecessors: No Data Available
Obsolete Names: No Data Available
Obsolete Parents: No Data Available
Synonomy: = Fraxinus latifolia (Oregon ash groves) Alliance (Sawyer et al. 2009) [61.960.00]
= Fraxinus latifolia Seasonally Flooded Forest Alliance (Keeler-Wolf et al. 2012)
= Fraxinus latifolia Alliance (Oregon ash groves) (Buck-Diaz et al. 2012)
= Fraxinus latifolia Seasonally Flooded Forest Alliance (Keeler-Wolf et al. 2012)
= Fraxinus latifolia Alliance (Oregon ash groves) (Buck-Diaz et al. 2012)
- 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]
- 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.
- Christy, J. A. 1991. Draft classification of native wetland plant communities in Oregon. Unpublished report prepared for the Oregon Natural Heritage Program, Portland, OR. 69 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.
- Frenkel, R. E., and E. F. Heinitz. 1987. Composition and structure of Oregon ash (Fraxinus latifolia) forest in William L. Finley National Wildlife Refuge, Oregon. Northwest Science 61:203-212.
- Hinschberger, M. S. 1978. Occurrence and relative abundance of small mammals associated with riparian and upland habitats along the Columbia River. Unpublished thesis, Oregon State University, Corvallis. 78 pp.
- Keeler-Wolf, T., P. E. Moore, E. T. Reyes, J. M. Menke, D. N. Johnson, and D. L. Karavidas. 2012. Yosemite National Park vegetation classification and mapping project report. Natural Resource Technical Report NPS/YOSE/NRTR--2012/598. National Park Service, Fort Collins, CO.
- Kunze, L. M. 1994. Preliminary classification of native, low elevation, freshwater wetland vegetation in western Washington. Washington State Department of Natural Resources, Natural Heritage Program. 120 pp.
- 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.
- Smith, S., and S. Smith. 1976. Vegetative types and landform classes. Pages 40-268 in: J. Tabor, editor. Inventory of riparian habitats and associated wildlife along the Columbia River. Final report prepared for Oregon State University Cooperative Wildlife Research Unit, Corvallis. 771 pp.