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CEGL000665 Populus fremontii - Platanus wrightii Riparian Forest

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Fremont Cottonwood - Arizona Sycamore Riparian Forest

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This is a lowland forested riparian association known from the Gila River watershed in New Mexico and has been reported from southwestern New Mexico and southern Arizona. It occurs in lowland river valleys at elevations ranging between 1180-1570 m (3875-5150 feet). The stream gradients are typically low, and channel substrates are gravelly or finer, but with pockets of cobbles. Typically, this type occurs as mature stands on older river terraces that are elevated several meters above the present riverbed and affected by only the largest flood events (25- to 100-year intervals). Occasionally the type occurs on lower bars that are more frequently flooded. Soils range from weakly developed Entisols on lower bars to more developed Inceptisols (deep, well-drained, stratified soils composed of sandy, loamy surface soils underlain by finer silt layers) on the upper terraces. Cobbles and rock may be present on the surface, or buried at lower depths. The soils tend to be dry on the surface most of the year, but may be periodically moist at depths within the rooting zone of the dominant trees and shrubs, particularly during spring runoff periods. Populus fremontii and Platanus wrightii form open to moderately closed, sprawling canopies (50-75% cover). In older stands, multi-boled trees can attain large sizes with diameters exceeding 1-3 m (3-10 feet) at breast height (dbh), and heights of up to 25 m (82 feet). Populus fremontii and Platanus wrightii regeneration is rare, but other trees, such as Juglans major, Fraxinus velutina, Acer negundo and occasionally the introduced Gleditsia triacanthos, may be present as saplings or subcanopy associates. On drier sites and in older stands, Juniperus deppeana may also be common. Undergrowth is diverse and variable with 79 species reported for the type, but only 23 more than once. With the exception of Baccharis salicifolia, Pluchea sericea, and Salix exigua, shrubs are generally poorly represented. The herbaceous undergrowth is characterized by scattered grasses and forbs and includes the wetland indicators Symphyotrichum praealtum and Lobelia cardinalis, along with upland grama grasses (Bouteloua curtipendula, Bouteloua eriopoda, and Bouteloua gracilis).

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Since Platanus wrightii reproduces on low, cobbly bars in the channel, mature stands of high terraces usually lack young trees. Saplings of Juglans major, Fraxinus velutina or Gleditsia triacanthos, which are drought- and shade-tolerant, may indicate a successional shift toward a drier community type. Adjacent lower bars are often dominated by early-successional communities such as Platanus wrightii - Alnus oblongifolia / Baccharis salicifolia. Where sycamores do not become established, for example on sandy or silty bars, Populus fremontii - Salix gooddingii / Salix exigua or Populus fremontii / Baccharis salicifolia communities may be prevalent. Large, flat and sparsely vegetated cobble bars may dissect the floodplain creating a relatively undulating surface topography. Intermittent channels that dissect the floodplain may be dominated by Chilopsis linearis and Ericameria nauseosa, while the outer floodplains are typically dominated by forests of Juglans major or Celtis laevigata var. reticulata.

Dick-Peddie (1993) reports a Populus fremontii / Platanus wrightii / Sparse Shrub / Mesic Grass - Forb vegetation type without description within his Broadleaf Cottonwood-Mixed Deciduous Series. Similarly, Brown et al. (1979) report a Platanus wrightii - Fraxinus velutina - Populus fremontii - mixed deciduous community without description as part of their Interior Southwestern Riparian Deciduous Forest and Woodland. Muldavin (1987) reports a Populus fremontii - Platanus wrightii / Baccharis salicifolia type that is synonymous with this association.

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

Floristics: Populus fremontii and Platanus wrightii form open to moderately closed, sprawling canopies (50-75% cover). In older stands, multi-boled trees can attain large sizes with diameters exceeding 1 to 3 m (3-10 feet) at breast height (dbh) and heights of up to 25 m (82 feet). Cottonwood and sycamore regeneration is rare, but other trees such as Juglans major, Fraxinus velutina, Acer negundo, and occasionally the introduced Gleditsia triacanthos may be present as saplings or subcanopy associates. On drier sites and in older stands, Juniperus deppeana may also be common. Undergrowth is diverse and variable with 79 species reported for the type, but only 23 more than once. With the exception of Baccharis salicifolia, Pluchea sericea, and Salix exigua, shrubs are generally poorly represented. The herbaceous undergrowth is characterized by scattered grasses and forbs and includes the wetland indicators Symphyotrichum praealtum (= Aster praealtus) and Lobelia cardinalis, along with upland grama grasses (Bouteloua curtipendula, Bouteloua eriopoda, and Bouteloua gracilis).

Dynamics:  No Data Available
Environmental Description:  This community type occurs in lowland river valleys at elevations ranging between 1180 and 1570 m (3875-5150 feet). The stream gradients are typically low, and channel substrates are gravelly or finer but with pockets of cobbles. Typically, this type occurs as mature stands on older river terraces that are elevated several meters above the present riverbed and affected by only the largest flood events (25- to 100-year intervals). Occasionally the type occurs on lower bars that are more frequently flooded. Soils range from weakly developed Entisols on lower bars to more developed Inceptisols (deep, well-drained, stratified soils composed of sandy, loamy surface soils underlain by finer silt layers) on the upper terraces. Cobbles and rock may be present on the surface or buried at lower depths. The soils tend to be dry on the surface most of the year but may be periodically moist at depths within the rooting zone of the dominant trees and shrubs, particularly during spring runoff periods.
Geographic Range: This association is restricted to the Gila River watershed in southwestern New Mexico (Catron and Grant counties) and southeastern Arizona.

Nations: US

States/Provinces:  AZ, NM


Confidence Level: Low

Confidence Level Comments: No Data Available
Grank: G2

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 A3803 Fremont Cottonwood - Velvet Ash - Goodding''s Willow Riparian Forest & Woodland Alliance A3803 1.B.3.Nd.2.b
Association CEGL000665 Fremont Cottonwood - Arizona Sycamore Riparian Forest CEGL000665 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: ? Platanus wrightii - Fraxinus velutina - Populus fremontii - mixed deciduous community (Brown et al. 1979)
= Populus fremontii - Platanus wrightii / Baccharis salicifolia type (Muldavin 1987)
? Populus fremontii / Platanus wrightii / Sparse Shrub / Mesic Grass - Forb Vegetation Type (Dick-Peddie 1993)
= Fremont Cottonwood-Arizona Sycamore 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: 08-02-04
  • 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.
  • 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.
  • Henry, R. J. 1981. Riparian vegetation of two mountain ranges in southwestern New Mexico. Unpublished thesis, New Mexico State University, Las Cruces.
  • Muldavin, E. 1987. Gila Riparian Preserve Design. Unpublished report prepared for The Nature Conservancy, New Mexico Field Office by New Mexico Natural Heritage Program, Albuquerque.
  • 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.
  • Stromberg, J. C. 1993a. Fremont cottonwood-Goodding willow riparian forests: A review of their ecology, threats, and recovery potential. Journal of the Arizona-Nevada Academy of Science 27(1):97-110.
  • 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.