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CEGL005961 Populus angustifolia - Acer negundo / Poa pratensis Ruderal Riparian Woodland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Narrowleaf Cottonwood - Box-elder / Kentucky Bluegrass Ruderal Riparian Woodland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This association is found in the Pecos and Gila river basins of north-central and southwestern New Mexico. It has been found at elevations ranging from 1770 to 2160 m (5800-7075 feet) and occurs in mountainous regions in moderately wide canyons where the river channel cuts through moderately steep to gently sloped terrain. The type can be found on low terraces with coarse to fine alluvial sediments and an undulating surface topography. Flooding is infrequent (every 10 to 25 years), but woody debris or smaller flood debris, stones, and areas of bare ground are common. Soils tend to be moist, young, weakly developed Entisols (Ustifluvents and Udifluvents). Some are more developed, moist Inceptisols (Endoaquepts and Ustochrepts). Generally, soils of this type are moderately drained and have moderate plant-available water (8%). They tend to be loamy but can have a rocky layer with depth. At lower depths soils may be periodically moist between 30 to 70 cm (1-2.5 feet), especially during high water events. This type is characterized in mature stands by a moderately closed canopy (>60%) dominated by Populus angustifolia with Acer negundo as a codominant. Other trees are sparse. Exotic grasses, such as Poa pratensis, Schedonorus pratensis, and Agrostis gigantea, among others, are well-represented and dominate the undergrowth. Shrubs, particularly twining, woody vines such as Clematis ligusticifolia or Parthenocissus quinquefolia are often present but not abundant.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: The community is naturally distributed along streambanks of moderate-sized streams and river corridors with unregulated river flows and few diversions. It is represented by middle-aged groves of deciduous trees. In southwestern systems, the trees are typically taller than the surrounding upland vegetation, and the riparian vegetation is conspicuous within the arid landscape. Reproduction of the cottonwoods is initiated on bare cobble bars or among the bank sediments. As cottonwoods mature and sites develop, Acer negundo and Juglans spp. are able to reproduce beneath the shaded canopy. Mature cottonwoods may eventually be fewer in number as the Acer negundo grow up into the higher canopy. While surface flooding may be infrequent within the stand, the community still relies on periodic high flows for continued maintenance. As with all mature riparian stands, reproduction and rejuvenation of the stand depends on high-energy floods that scour bars and create moist open areas for germination. The denser shade in some stands and high cover provide excellent wildlife habitat. The presence of Poa pratensis may be indicative of past excessive grazing by livestock.

Brown et al. (1979) recognized an Acer negundo - Populus angustifolia - mixed deciduous Association as part of a Mixed Broadleaf Series within a Rocky Mountain Riparian Deciduous Forest Biome. Similarly, Dick-Peddie (1993) lists a Populus angustifolia / Acer negundo type within a Narrowleaf Cottonwood-Mixed Deciduous Series of Montane Riparian zone for New Mexico. The Acer negundo - Populus angustifolia / Cornus sericea Association identified in Colorado by the Colorado Natural Heritage Program may have affinities to this type (Baker 1984a). Szaro (1989) described both an Acer negundo Community Type and an Acer negundo - Mixed Deciduous Community Type for southern New Mexico and Arizona with canopy codominants that include Alnus oblongifolia, Salix irrorata, Juglans major, Fraxinus pennsylvanica, Populus fremontii, and Populus angustifolia.

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

Floristics: This type is characterized in mature stands by a moderately closed canopy (>60%) dominated by Populus angustifolia with Acer negundo as a codominant. Cottonwood reproduction occurs vegetatively, and Acer negundo reproduction is common beneath the shaded canopy. Other trees are sparse. Exotic and invasive grasses, such as Poa pratensis, Schedonorus pratensis (= Festuca pratensis), and Agrostis gigantea, among others, are well-represented and dominate the undergrowth. Shrubs, particularly twining, woody vines such as Clematis ligusticifolia or Parthenocissus quinquefolia are often present but not abundant. Six native wetland indicators have been recorded for the type; they are Mimulus guttatus, Veronica americana, Heracleum maximum, Ambrosia trifida, and Rudbeckia laciniata.

Dynamics:  No Data Available
Environmental Description:  This community has been found at elevations ranging from 1770 to 2160 m (5800-7075 feet). It occurs in mountainous regions in moderately wide canyons where the river channel cuts through moderately steep to gently sloped terrain. Streamflows are either perennial or intermittent. Often there are riffles and shallow pools created by the cobbles, gravels, and debris that line the riverbed and banks. Depositional features are limited through steeper reaches, but well-vegetated bars and terraces occur through the wider valleys. The type can be found on low terraces with coarse to fine alluvial sediments and an undulating surface topography. Flooding is infrequent (every 10 to 25 years), but woody debris or smaller flood debris, stones, and areas of bare ground are common. In closed-canopy stands that are wetter, mosses occur in small patches over bare ground or on rocks and cobbles. In drier, open-canopy stands, bare ground is typically loose and sandy. Soils tend to be moist, young, weakly developed Entisols (Ustifluvents and Udifluvents). Some are more developed, moist Inceptisols (Endoaquepts and Ustochrepts). Generally, soils of this type are moderately drained and have moderate plant-available water (8%). They tend to be loamy but can have a rocky layer with depth. At lower depths soils may be periodically moist between 30 to 70 cm (1-2.5 feet), especially during high water events.
Geographic Range: This association is found in the Pecos and Gila River basins of north-central and southwestern New Mexico.

Nations: US

States/Provinces:  NM


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNA

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.Nd Western North American Interior Flooded Forest Division D013 1.B.3.Nd
Macrogroup 1.B.3.Nd.90 Interior West Ruderal Flooded & Swamp Forest & Woodland Macrogroup M298 1.B.3.Nd.90
Group 1.B.3.Nd.90.a Tamarisk species - Russian-olive Ruderal Riparian Forest & Scrub Group G510 1.B.3.Nd.90.a
Alliance A4155 Box-elder - Cottonwood species - Spruce species Ruderal Riparian Forest Alliance A4155 1.B.3.Nd.90.a
Association CEGL005961 Narrowleaf Cottonwood - Box-elder / Kentucky Bluegrass Ruderal Riparian Woodland CEGL005961 1.B.3.Nd.90.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: ? Acer negundo - Populus angustifolia / Cornus sericea Association (Baker 1984a)
? Acer negundo - Populus angustifolia - mixed deciduous Association (Brown et al. 1979)
? Acer negundo - Mixed Deciduous Community Type (Szaro 1989)
? Acer negundo Community Type (Szaro 1989)
? Populus angustifolia / Acer negundo Vegetation Type (Dick-Peddie 1993)
= Narrowleaf Cottonwood-Boxelder/Kentucky Bluegrass CT (Muldavin et al. 2000a)
Concept Author(s): E. Muldavin et al. (2000a)

Author of Description: E. Muldavin et al.

Acknowledgements: No Data Available

Version Date: 07-19-04
  • Baker, W. L. 1984a. A preliminary classification of the natural vegetation of Colorado. Great Basin Naturalist 44(4):647-676.
  • Brown, D. E., C. H. Lowe, and C. P. Pase. 1979. A digitized classification system for the biotic communities of North America with community (series) and association examples for the Southwest. Journal of the Arizona-Nevada Academy of Science 14:1-16.
  • Dick-Peddie, W. A. 1993. New Mexico vegetation: Past, present, and future. University of New Mexico Press, Albuquerque. 244 pp.
  • Muldavin, E., P. Durkin, M. Bradley, M. Stuever, and P. Mehlhop. 2000a. Handbook of wetland vegetation communities of New Mexico. Volume I: Classification and community descriptions. Final report to the New Mexico Environment Department and the Environmental Protection Agency prepared by the New Mexico Natural Heritage Program, University of New Mexico, Albuquerque.
  • Muldavin, E., Y. Chauvin, P. Neville, T. Neville, L. Arnold, P. Arbetan, and A. Fettes. 2012b. A vegetation classification and map: Pecos National Historical Park. Natural Resource Technical Report NPS/SOPN/NRTR--2012/601. National Park Service, Fort Collins, CO.
  • Szaro, R. C. 1989. Riparian forest and scrubland community types of Arizona and New Mexico. Desert Plants Special Issue 9(3-4):70-139.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.