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CEGL000672 Populus balsamifera ssp. trichocarpa / Cornus sericea Riparian Forest

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Black Cottonwood / Red-osier Dogwood Riparian Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This association has been documented from Washington south to northern California and eastward to Idaho and Montana west of the Continental Divide, as well as central Montana. It occurs over a broad elevation range of 610 to 2135 m (2000-7000 feet) where Populus balsamifera ssp. trichocarpa is the dominant cottonwood at elevations considered relatively low to mid gradient. This forest type occupies alluvial terraces of major rivers and streams, point bars, side bars, mid-channel bars, delta bars, an occasional lake or pond margin, and even creeps onto footslopes and lower subirrigated slopes of hilly or mountainous terrain. Stands occasionally occur on upper positions of moderate to steep toeslopes and colluvial fans at the base of avalanche chutes. Many of these sites are flooded in the spring and dry deeply by summer''s end; capillary action keeps upper portions of the soil profile moist. Other sites are merely subirrigated. Populus balsamifera ssp. trichocarpa dominates the overstory with average cover values ranging from approximately 30-90%. Populus angustifolia, Populus tremuloides, Betula papyrifera, and Salix amygdaloides are common subordinates. Several conifer species can be present with low cover (2-10%) in the upper canopy or as young saplings and are never consistently present. Conifers include Tsuga heterophylla, Pseudotsuga menziesii, Abies lasiocarpa, and Picea engelmannii. The shrub layer comprises at least 25% cover, with Cornus sericea diagnostic for the type and having anywhere from 1-90% cover; other shrub taxa with high constancy include Symphoricarpos spp., Rosa spp., Salix spp., Crataegus spp., Amelanchier alnifolia, Salix lutea, Acer glabrum, and Alnus incana. There are no graminoids exhibiting high constancy, though any one of a number of disturbance-associated exotics can manifest high coverages. Native grasses such as Calamagrostis canadensis, Glyceria striata, and Deschampsia cespitosa can be abundant in undisturbed stands, but this is increasingly less common. Maianthemum stellatum, Galium triflorum, Solidago canadensis, and Equisetum spp. are the only forbs that exhibit even relatively high constancy across the range of the type.

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. If it were renamed as a dominance type, the species would include Populus balsamifera ssp. trichocarpa and Betula papyrifera. In the concept for this association, stands containing both Populus balsamifera ssp. trichocarpa and Populus tremuloides are defined as belonging to a Populus balsamifera ssp. trichocarpa alliance, rather than a Populus tremuloides alliance. This is because Populus balsamifera ssp. trichocarpa generally has a narrower ecological amplitude and better serves as a diagnostic species. More than half of the identified stands in Glacier National Park have less than 60% tree canopy cover, which means that a significant portion of this association qualifies physiognomically as woodland, rather than as forest as currently classified. There are strongly discordant criteria as to how much Cornus sericea cover should be represented (ranging from 1-25%) for a stand to be considered a member of this association; however, if Cornus is the dominant, or at least the most abundant of all shrubs present, it would fall into this type.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available

Floristics: Populus balsamifera ssp. trichocarpa dominates the overstory with cover values ranging from approximately 30-90%. Populus angustifolia, Populus tremuloides, Betula papyrifera, and Salix amygdaloides are common subordinates. Several conifer species can be present with low cover (2-10%) in the upper canopy or as young saplings and are never consistently present. Conifers include Tsuga heterophylla, Abies lasiocarpa, Pseudotsuga menziesii, and Picea engelmannii. The shrub layer comprises at least 10% cover, with Cornus sericea diagnostic for the type and having anywhere from 1-90% cover; other shrub taxa with high constancy include Symphoricarpos spp., Ribes spp., Rosa spp., Salix spp., Crataegus spp., Amelanchier alnifolia, Salix lutea, and Alnus incana. There are no graminoids exhibiting high constancy, though any one of a number of disturbance-associated exotics can manifest high coverages. Native grasses such as Calamagrostis canadensis, Calamagrostis rubescens, Carex geyeri, Glyceria striata, and Deschampsia cespitosa can be abundant in undisturbed stands, but this is increasingly less common. Maianthemum stellatum, Galium triflorum, Solidago canadensis, and Equisetum spp. are the only forbs that exhibit even relatively high constancy across the range of the type.

Dynamics:  This is a successional community that colonizes moist, newly deposited alluvium exposed to full sunlight; in the absence of fluvial disturbance it is capable of developing into conifer-dominated communities belonging to alliances as diverse as Tsuga heterophylla, Pseudotsuga menziesii, or Picea spp. if sites are no longer subject to flooding or avalanche disturbance. This association is also found on frequently avalanched sites, with subirrigation during the summer from snowmelt. In these situations the trees may be dwarfed, broken, bent or otherwise damaged by avalanche impacts, resulting in the canopy being a mix of both Populus and Cornus or other shrubs.
Environmental Description:  This association has been documented from Washington south to northern California and eastward to Idaho, Montana and Wyoming. It occurs over a broad elevational range of 610 to 2135 m (2000-7000 feet) where Populus balsamifera ssp. trichocarpa is the dominant cottonwood. This forest type occupies alluvial terraces of major rivers and streams, point bars, side bars, mid-channel bars, delta bars, an occasional lake or pond margin, and even creeps onto footslopes and lower subirrigated slopes of hilly or mountainous terrain. Stands occasionally occur on upper positions of moderate to steep toeslopes and colluvial fans at the base of avalanche chutes or erosional gullies, where they are subject to avalanche or flash-flood disturbance. Many of these sites are flooded in the spring and dry deeply by summer''s end; capillary action keeps upper portions of the soil profile moist. Other sites are merely subirrigated. Adjacent wetter sites are dominated by a suite of wetland Salix spp., Alnus incana, wetland-associated Carex spp. often including Carex utriculata, Carex aquatilis and Carex buxbaumii, or Typha latifolia-dominated communities. Adjacent drier sites are dominated by Populus balsamifera ssp. trichocarpa or Populus tremuloides types or any of a number of conifer-dominated types.
Geographic Range: This association has been documented from Washington south to northern California and eastward to Idaho, Montana and Wyoming. It also occurs north along the Front Range of Montana into southern Alberta, Canada.

Nations: CA,US

States/Provinces:  AB, CA, ID, MT, OR, WA, WY


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: G3G4

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.Nc Rocky Mountain-Great Basin Montane Flooded & Swamp Forest Division D195 1.B.3.Nc
Macrogroup 1.B.3.Nc.1 Engelmann Spruce - Narrowleaf Cottonwood / Red-osier Dogwood Riparian & Swamp Forest Macrogroup M034 1.B.3.Nc.1
Group 1.B.3.Nc.1.c Northern Rocky Mountain Lowland-Foothill Riparian Forest Group G796 1.B.3.Nc.1.c
Alliance A0311 Black Cottonwood Northern Rocky Mountain Riparian Forest Alliance A0311 1.B.3.Nc.1.c
Association CEGL000672 Black Cottonwood / Red-osier Dogwood Riparian Forest CEGL000672 1.B.3.Nc.1.c
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: < Populus balsamifera ssp. trichocarpa / Alnus incana - Cornus sericea ssp. sericea Association (Crowe et al. 2004)
= Populus balsamifera ssp. trichocarpa/Cornus sericea Forest (Crawford et al. 2009)
= Populus balsamiferia ssp. trichocarpa / Cornus sericea Temporarily Flooded Forest (Crawford 2003)
= Populus trichocarpa / Cornus stolonifera Community Type (Hansen et al. 1995) [(p.244)]
= Populus trichocarpa / Cornus stolonifera Community Type (Hall and Hansen 1997) [(p.138)]
= Populus trichocarpa / Cornus stolonifera Forest (Evans 1989a) [(p.17) - this synonym is cited in Evans 1989a, from Caicco 1988, and Hansen et al. 1988.]
= Populus trichocarpa / Cornus stolonifera Forest (Kovalchik 1993) [(p.86)]
= Black cottonwood - Engelmann spruce / mountain alder - red-osier dogwood community type (Kovalchik 1987) [(p.136)]
Concept Author(s): S.V. Cooper

Author of Description: S.V. Cooper and G. Kittel

Acknowledgements: No Data Available

Version Date: 07-13-04
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