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CEGL000683 Quercus emoryi / Bouteloua curtipendula Scrub Woodland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Emory Oak / Sideoats Grama Scrub Woodland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This diverse Madrean woodland savanna association is known from the "Borderlands" area of southeastern Arizona and southwestern New Mexico, extending west to Buenos Aires National Wildlife Area and east into Trans-Pecos Texas, and in the Sierra Del Carmen of northeastern Coahuila, Mexico. Stands occur on gentle to moderate hillslopes of northerly aspects, and elevations range from 1380-1980 m (4528-6500 feet). Substrates are igneous volcanic rhyolites, andesites and tuffs. This association is characterized by moderately open canopies (30% cover) dominated by Quercus emoryi. Quercus grisea or Quercus arizonica along with Juniperus deppeana, Pinus discolor, or Pinus cembroides can be present, but they are not dominant or codominant. The understory is moderately diverse (55 species have been recorded for the association), characteristically grassy, and dominated by Bouteloua curtipendula. Other common grasses include Bouteloua gracilis, Muhlenbergia emersleyi, and Eragrostis intermedia.

Diagnostic Characteristics: Oak savannas having scattered trees (usually exceeding 3.7 m [12 feet] tall) with Quercus emoryi attaining < 5% cover; with grassy understory on alluvial soils.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: The western Sierra Madre representatives of this type may have somewhat different understory compositions from those of the eastern Sierra Madre.

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

Floristics: This association is characterized by moderately open canopies (30% cover) dominated by Quercus emoryi. Quercus grisea or Quercus arizonica along with Juniperus deppeana, Pinus discolor, or Pinus cembroides can be present, but they are not dominant or codominant. The understory is moderately diverse (55 species have been recorded for the association), characteristically grassy, and dominated by Bouteloua curtipendula. Other common grasses include Bouteloua gracilis, Muhlenbergia emersleyi, and Eragrostis intermedia.

Dynamics:  Oak woodlands having a continuous grass understory experience rapidly spreading fires. Fire effects depend on tree size, fire severity, and drought stress. Small-sized Quercus emoryi may be top-killed by fire. Large trees survive fires of low severity. Well-developed root systems of mature Quercus emoryi buffer the effects of drought and allow rapid regeneration by sprouting vigorously from root crown and stump after top damage. It recovers quickly from the effects of burning. Unless covered by an insulating layer of soil, acorns are probably killed by fire.
Environmental Description:  This diverse Madrean woodland savanna association is known from the "Borderlands" area of southeastern Arizona and southwestern New Mexico, extending west to Buenos Aires National Wildlife Area and east into Trans-Pecos Texas, and in the Sierra Del Carmen of northeastern Coahuila, Mexico. Stands occur on gentle to moderate hillslopes of northerly aspects, and elevations range from 1380-1980 m (4528-6500 feet). Substrates are igneous volcanic rhyolites, andesites and tuffs.
Geographic Range: This association is known from the Borderlands area of southeastern Arizona and southwestern New Mexico, extending west to Buenos Aires National Wildlife Area and east into Trans-Pecos Texas, and in the Sierra Del Carmen of northeastern Coahuila, Mexico. It may occur elsewhere in southwestern New Mexico, southeastern Arizona, and northern Mexico.

Nations: MX,US

States/Provinces:  AZ, MXCHH, MXCOA, MXSON, NM, TX


Confidence Level: Low

Confidence Level Comments: No Data Available
Grank: G3

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.1 Warm Temperate Forest & Woodland Formation F018 1.B.1
Division 1.B.1.Nd Madrean-Balconian Forest & Woodland Division D060 1.B.1.Nd
Macrogroup 1.B.1.Nd.1 Alligator Juniper - Mexican Pinyon - Arizona White Oak Madrean Lowland Evergreen Woodland Macrogroup M010 1.B.1.Nd.1
Group 1.B.1.Nd.1.a Arizona White Oak - Emory Oak - Mexican Blue Oak Woodland Group G201 1.B.1.Nd.1.a
Alliance A3101 Arizona White Oak - Emory Oak - Gray Oak Scrub Woodland Alliance A3101 1.B.1.Nd.1.a
Association CEGL000683 Emory Oak / Sideoats Grama Scrub Woodland CEGL000683 1.B.1.Nd.1.a
Concept Lineage: merged

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Quercus emoryi / Bouteloua curtipendula (Stuever and Hayden 1997b)
= Quercus emoryi / Bouteloua curtipendula PA (Bourgeron et al. 1993b)
= Quercus emoryi / Bouteloua curtipendula PA (Muldavin et al. 1998a)
= Quercus emoryi / Bouteloua curtipendula PA (Wood et al. 1999)
= Quercus emoryi / Bouteloua curtipendula PA (Bourgeron et al. 1995a)
< IB3e. Emory Oak Woodland (Allard 1990)
Concept Author(s): E. Muldavin et al. (1998a)

Author of Description: E. Muldavin and K.A. Schulz

Acknowledgements: No Data Available

Version Date: 10-16-18
  • Allard, D. J. 1990. Southeastern United States ecological community classification. Interim report, Version 1.2. The Nature Conservancy, Southeast Regional Office, Chapel Hill, NC. 96 pp.
  • Bourgeron, P. S., L. D. Engelking, H. C. Humphries, E. Muldavin, and W. H. Moir. 1993b. Assessing the conservation value of the Gray Ranch: Rarity, diversity and representativeness. Unpublished report prepared for The Nature Conservancy by the Western Heritage Task Force, Boulder, CO. (Volume I and II).
  • Bourgeron, P. S., L. D. Engelking, H. C. Humphries, E. Muldavin, and W. H. Moir. 1995a. Assessing the conservation value of the Gray Ranch: Rarity, diversity and representativeness. Desert Plants 11(2-3):3-68.
  • 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.
  • Diamond, D. D. 1993. Classification of the plant communities of Texas (series level). Unpublished document. Texas Natural Heritage Program, Austin. 25 pp.
  • Muldavin, E., V. Archer, and P. Neville. 1998a. A vegetation map of the Borderlands Ecosystem Management Area. Final report submitted to USDA Forest Service, Rocky Mountain Experiment Station, Flagstaff, AZ, by the New Mexico Natural Heritage Program, University of New Mexico, Albuquerque, NM. 58 pp.
  • NHNM [Natural Heritage New Mexico]. No date. Unpublished data on file. Natural Heritage New Mexico, University of New Mexico, Albuquerque.
  • Schulz, K. A. 2004. Vegetation classification of Buenos Aires National Wildlife Refuge, Arizona. Unpublished report submitted to USDI Fish and Wildlife Service. NatureServe, Western Regional Office, Boulder, CO.
  • Stuever, M. C., and J. S. Hayden. 1997b. Plant associations of Arizona and New Mexico. Volume 2: Woodlands. USDA Forest Service, Southwestern Region, Habitat Typing Guides. 196 pp.
  • USFS [U.S. Forest Service]. 1987b. Forest and woodland habitat types (plant associations) of Arizona south of the Mogollon Rim and southwestern New Mexico. USDA Forest Service, Southwestern Region, Albuquerque, NM. Second edition, 168 pp. plus insert.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.
  • Wood, S., G. Harper, E. Muldavin, and P. Neville. 1999. Vegetation map of the Sierra del Carmen, U.S.A. and Mexico. Final report submitted to Big Bend National Park by the New Mexico Natural Heritage Program, University of New Mexico, Albuquerque, NM. 57 pp.