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A3798 Populus deltoides ssp. wislizeni - Populus deltoides ssp. monilifera - Salix amygdaloides Riparian Woodland Alliance

Type Concept Sentence: This alliance consists of woodlands dominated by Populus deltoides ssp. wislizeni, Populus deltoides ssp. monilifera, or Salix amygdaloides. Other tree species include Acer negundo. Stands are found on alluvial floodplains, terraces and streambanks of rivers and streams, and sometimes around lakes and ponds. These stands occur along rivers and streams of Wyoming, Colorado, New Mexico, and on to the Colorado Plateau of Utah.


Common (Translated Scientific) Name: Rio Grande Cottonwood - Plains Cottonwood - Peachleaf Willow Riparian Woodland Alliance

Colloquial Name: Rio Grande Cottonwood - Plains Cottonwood - Peachleaf Willow Riparian Woodland

Hierarchy Level:  Alliance

Type Concept: This alliance is dominated by Populus deltoides ssp. wislizeni, Populus deltoides ssp. monilifera, or Salix amygdaloides. Other tree species include Acer negundo. Shrub species present many include Artemisia tridentata, Prunus virginiana, Rhus trilobata, Salix exigua, and Symphoricarpos occidentalis. Typical herbaceous species include Carex spp., Distichlis spicata, Elymus spp., Equisetum spp., Juncus spp., and Pascopyrum smithii. Exotics found in this alliance are Poa pratensis, Melilotus officinalis, and Bromus inermis, among many others. Stands of this alliance are found on alluvial floodplains and terraces of rivers and streams, and sometimes around lakes and ponds. These communities tolerate and depend on periodic flooding and seasonal soil saturation in the spring and after heavy rains. The soils are silts, loams, and sands, and are derived from alluvial material. This alliance occurs near rivers and large streams of Montana, Wyoming, Colorado, Idaho, Arizona and New Mexico; from the western slope of Colorado it extends into mountain valleys and on to the Colorado Plateau of Utah.

Diagnostic Characteristics: Riparian gallery forests and woodland dominated by Populus deltoides ssp. wislizeni, Populus deltoides ssp. monilifera, or Salix amygdaloides.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: No Data Available

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: The tree layer is dominated by tall (20-35 m) single-stemmed, deciduous species. The canopy is open, generally forming 25-60% cover. The herbaceous layer is dominated by both graminoids and forbs with up to 20% cover.

Floristics: This alliance is dominated by Populus deltoides ssp. wislizeni, Populus deltoides ssp. monilifera, or Salix amygdaloides. Secondary canopy species include Acer negundo or (rarely) Populus angustifolia. A shrub layer may be present, including Cornus sericea, Prunus virginiana, Salix exigua, Salix ligulifolia, Salix lucida, Salix lutea, Symphoricarpos occidentalis, and others. Herbaceous layer may have Carex pellita (= Carex lanuginosa), Carex spp., Cenchrus longispinus, Elymus spp., Equisetum spp., Glycyrrhiza lepidota, Juncus spp., Pascopyrum smithii, Phalaris arundinacea, and Poa palustris. Common exotics found in this alliance are Bromus inermis, Cirsium arvense, Melilotus officinalis (= Melilotus albus), and Poa pratensis.

Dynamics:  Cottonwood forests grow within an alluvial environment that is continually changing due to the ebb and flow of the river. Riparian vegetation successional stage is "re-set" by flooding disturbance. Cottonwood communities are early-, mid- or late-seral, depending on the age class of the trees and the associated species of the stand. Mature cottonwood stands do not regenerate in place, but regenerate in different settings up and down a river reach. Over time, a healthy riparian area supports all stages of cottonwood communities. The process of cottonwood regeneration is well-documented. Periodic flooding events can leave sandbars of bare, mineral substrate. Cottonwood seedlings germinate and become established on newly-deposited, moist sandbars. In the absence of large floods in subsequent years, seedlings begin to trap sediment. In time, the sediment accumulates and the sandbar rises. The young forest community is then above the annual flood zone of the river channel. In addition, seasonal floods that leave fresh deposits of sediment are also areas available for colonization. This process often favors the establishment of aggressive native and exotic plants, as well as cottonwood seedlings.

Salix amygdaloides requires a moist, mineral substrate for seeds to germinate. Seeds can germinate under a sparse canopy of vegetation (Johnson 1992, cited in Jones and Walford 1995).

Environmental Description:  Stands of this alliance are found on level to gently sloping topography along rivers, streams, lakes, and ponds. The areas may have been very recently deposited by water action or they may have been deposited earlier and occupied by other communities. The water table fluctuates with the level of the adjacent water body. This can lead to periods of flooding and soil saturation in the spring and after heavy rains and also to periods of drought when the water level falls in the summer and fall. The soils are silts, loams, and sands, and are derived from alluvial material. Stands are located on immediate streambanks, or on distance river terraces, in backwater areas and overflow channels of large rivers, on narrow floodplains of small creeks, and on the edges of ponds and lakes. The water table is within 1 m of the soil surface during the growing season (Hansen et al. 1995), and the vegetation is tolerant of prolonged flooding.

Geographic Range: This alliance occurs near rivers and large streams of Montana, Wyoming, Colorado, Idaho, Arizona and New Mexico; from the western slope of Colorado it extends into mountain valleys and on to the Colorado Plateau of Utah.

Nations: CA,US

States/Provinces:  AZ, CO, ID, MT, NM, UT, WY




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available


Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: ? Salix amygdaloides Community Type (Hansen et al. 1995)
>< Cottonwood: 63 (Eyre 1980)
>< Eastern Broadleaf Forests: 98: Northern Floodplain Forest (Populus-Salix-Ulmus) (Küchler 1964)
? Peachleaf Willow Dominance Type (Jones and Walford 1995)

Concept Author(s): G. Kittel, in Faber-Langendoen et al. (2013)

Author of Description: G. Kittel

Acknowledgements: No Data Available

Version Date: 09-29-16

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