Print Report

CEGL000666 Populus fremontii / Salix exigua Riparian Forest

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Fremont Cottonwood / Narrowleaf Willow Riparian Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This association is documented from along large rivers in Utah, southwestern New Mexico, and Arizona. Characteristic of this deciduous forest is the dominance of Populus fremontii in the moderately dense to dense tree canopy and Salix exigua in the tall-shrub layer; in some stands Forestiera pubescens is common. This is one of the wettest riparian forests. Salix gooddingii or Baccharis salicifolia are not abundant or are absent. Other associated species include Castilleja linariifolia, Distichlis spicata, Leymus cinereus, Muhlenbergia asperifolia, Oxytenia acerosa, Phragmites australis, and species of Equisetum, Juncus, and Carex. Introduced species such as Elaeagnus angustifolia, Tamarix spp., Poa pratensis, Melilotus spp., and other exotic forage species are often present in disturbed stands. Stands occur on streambanks, stable bars and low elevations of the active floodplain. Substrates are typically relatively recently deposited alluvium. Periodic flooding is required for the growth, maintenance and reproduction of this forest.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association is largely known and described from National Park Service inventory efforts in the Colorado Plateau. Salix gooddingii is not present and that distinguishes it from the similar Populus fremontii - Salix gooddingii / Salix exigua Riparian Forest (CEGL002684). This association was not reported in the Handbook of Wetland Vegetation Communities of New Mexico (Muldavin et al. 2000a) and needs further review to distinguish it from similar associations such as ~Populus fremontii - Salix gooddingii / Salix exigua Riparian Forest (CEGL002684)$$. Part of the confusion is related to a taxonomic change in Rio Grande cottonwood from Populus fremontii var. wislizeni S. Wats. to Populus deltoides ssp. wislizeni (S. Wats.) Eckenwalder. This change resulted in part of this association (central NM along the Rio Grande) being moved into ~Populus deltoides (ssp. wislizeni, ssp. monilifera) / Salix exigua Riparian Woodland (CEGL002685)$$. More work is needed to determine the range and possible areas of overlap between these two cottonwood species, and vegetation types in which they are important. There may be a mix up with this type occurring at Aztec Ruins National Monument and Chaco Culture National Historical Park as Populus fremontii does not occur in San Juan County according to USDA PLANTS (USDA NRCS n.d.); nor is this type reported for New Mexico by Muldavin et al. (2000a). This is likely due to the old name of Rio Grande cottonwood (Populus fremontii S. Watson var. wislizeni). Global description currently does not specify northwestern New Mexico.

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

Floristics: This association is characterized by an open to dense, deciduous tree canopy (10 to 75% cover) that is dominated by Populus fremontii with Salix exigua dominating the tall-shrub layer. Acer negundo may be present in the tree canopy, but Salix gooddingii is typically not present. Baccharis salicifolia is also typically not abundant in the shrub layer, but a variety of other riparian and upland shrub species may be present, including Betula occidentalis, Amelanchier spp., Ericameria nauseosa, Chrysothamnus linifolius, Rhus aromatica, Gutierrezia sarothrae, Artemisia tridentata, Forestiera pubescens, Pluchea sericea, Sarcobatus vermiculatus or Quercus gambelii. The herbaceous layer is generally sparse, depending on the density of the shrub and tree layers. Castilleja linariifolia, Distichlis spicata, Elymus canadensis, Elymus trachycaulus, Leymus cinereus, Muhlenbergia asperifolia, Oxytenia acerosa, Artemisia ludoviciana, Artemisia campestris, Phragmites australis, and species of Equisetum, Juncus, and Carex are commonly present (Szaro 1989, Muldavin et al. 2000a). Introduced species such as Elaeagnus angustifolia, Tamarix spp., Alhagi maurorum, Medicago sativa, Melilotus officinalis, Bromus spp., and Poa pratensis are often present in disturbed stands.

Dynamics:  Periodic flooding and a high water table are required for the growth, maintenance and reproduction of this forest.
Environmental Description:  This riparian forest association is documented from along large rivers in southwestern Utah, southwestern New Mexico, and Arizona. Sites include perennial streambanks, riverbanks, wash, valley, and canyon bottoms, drainage channels, terraces, and floodplains. Elevation ranges from 1050-1950 m (3445-6400 feet). Stands are found on stable bars in floodplains and along streambanks in canyons, where the water table is still high and flooding occurs less than annually. Substrates are typically relatively recently deposited alluvium. Stream gradient is typically gentle, and soils are rapidly to somewhat poorly drained, and range from loamy sand to silty clays derived from alluvium (Szaro 1989, Muldavin et al. 2000a).
Geographic Range: This riparian forest is known from southwestern New Mexico (Gila River), and in the Colorado Plateau of northwestern New Mexico, southern Utah and northern Arizona (Colorado River and tributaries such as the Fremont and Virgin rivers). It likely occurs elsewhere in the southwestern U.S.

Nations: US

States/Provinces:  AZ, NM, UT


Confidence Level: Moderate

Confidence Level Comments: No Data Available
Grank: GNR

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.2 Interior Warm & Cool Desert Riparian Forest Macrogroup M036 1.B.3.Nd.2
Group 1.B.3.Nd.2.b Western Interior Riparian Forest & Woodland Group G797 1.B.3.Nd.2.b
Alliance A0644 Fremont Cottonwood Great Basin Riparian Forest Alliance A0644 1.B.3.Nd.2.b
Association CEGL000666 Fremont Cottonwood / Narrowleaf Willow Riparian Forest CEGL000666 1.B.3.Nd.2.b
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: ? Populus fremontii / Salix exigua (Sawyer et al. 2009) [61.130.17]
< Populus fremontii Community Type (Szaro 1989)
Concept Author(s): E. Milford and E. Muldavin

Author of Description: E. Milford, E. Muldavin, K.A. Schulz, J. Coles, G. Kittel

Acknowledgements: No Data Available

Version Date: 08-03-16
  • 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.
  • Clark, D., M. Dela Cruz, T. Clark, J. Coles, S. Topp, A. Evenden, A. Wight, G. Wakefield, and J. Von Loh. 2009. Vegetation classification and mapping project report, Capitol Reef National Park. Natural Resource Report NPS/NCPN/NRTR--2009/187. National Park Service, Fort Collins, CO. 882 pp.
  • Cogan, D., M. Reid, K. Schulz, and M. Pucherelli. 2004. Zion National Park, Utah 1999-2003. Vegetation Mapping Project. Technical Memorandum 8260-03-01. Remote Sensing and GIS Group Technical Service Center, Bureau of Reclamation, Denver, CO. Appendix F: Vegetation Association Descriptions for Zion.
  • Coles, J., A. Tendick, G. Manis, A. Wight, G. Wakefield, J. Von Loh, and A. Evenden. 2009a. Vegetation classification and mapping project report, Arches National Park. Natural Resource Technical Report NPS/NCPN/NRTR--2009/253. National Park Service, Fort Collins, CO. 544 pp.
  • Coles, J., M. Hansen, and K. Thomas. 2003. Wupatki National Monument, Arizona, vegetation classification and distribution: A USGS-NPS Vegetation Mapping Program study. Southwest Biological Science Center, U.S. Geological Survey Open-file Report. [in preparation]
  • Hansen, M., J. Coles, K. A. Thomas, D. Cogan, M. Reid, J. Von Loh, and K. Schulz. 2004b. USGS-NPS Vegetation Mapping Program: Wupatki National Monument, Arizona, vegetation classification and distribution. U.S. Geological Survey Technical Report. Southwest Biological Science Center, Flagstaff, AZ. 229 pp.
  • Muldavin, E., B. Sims, and L. Johnson. 1993b. Pecos Wild and Scenic River in stream flow report. Final report prepared for the USDA Forest Service, Santa Fe National Forest, Santa Fe, NM.
  • 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.
  • NHNM [Natural Heritage New Mexico]. No date. Unpublished data on file. Natural Heritage New Mexico, University of New Mexico, Albuquerque.
  • Romme, W. H., K. D. Heil, J. M. Porter, and R. Fleming. 1993. Plant communities of Capitol Reef National Park, Utah. USDI National Park Service, Technical Report NPS/NAUCARE/NRTER-93/02. Cooperative Park Studies Unit, Northern Arizona University. 37 pp.
  • Salas, D. E., D. Wegner, and L. Floyd-Hanna. 2009. Vegetation mapping and classification report: Aztec Ruins National Monument. Natural Resource Technical Report NPS/SCPN/NRTR--2009/244. National Park Service, Fort Collins, CO. 90 pp.
  • Salas, D., L. Floyd-Hanna, and D. Hanna. 2011. Vegetation classification and mapping project report: Chaco Culture National Historical Park. Natural Resource Technical Report NPS/SCPN/NRTR--2011/452. National Park Service, Fort Collins, CO. 142 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.
  • Szaro, R. C. 1989. Riparian forest and scrubland community types of Arizona and New Mexico. Desert Plants Special Issue 9(3-4):70-139.
  • Tendick, A., J. Coles, K. Decker, M. Hall, J. Von Loh, T. Belote, A. Wight, G. Wakefield, and A. Evenden. 2012. Vegetation classification and mapping project report, Canyonlands National Park. Natural Resource Technical Report NPS/NCPN/NRTR--2012/577. National Park Service, Fort Collins, CO.
  • Tendick, A., J. Spence, M. Reid, K. Shulz, G. Kittel, K. Green, A. Wight, and G. Wakefield. 2017. Vegetation classification and mapping project report, Glen Canyon National Recreation Area and Rainbow Bridge National Monument. Natural Resource Report NPS/NCPN/NRR—2017/1500. National Park Service, Fort Collins, CO. 1464 pp.
  • USDA NRCS [Natural Resources Conservation Service]. No date. The PLANTS Database. USDA Natural Resources Conservation Service, National Plant Data Center, Baton Rouge, LA. [http://plants.usda.gov/]
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.