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CEGL000785 Pinus edulis / Muhlenbergia pauciflora Woodland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Two-needle Pinyon / New Mexico Muhly Woodland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This is a major community of the San Andres and Oscura mountains of New Mexico and is also known from the Sacramento and Capitan mountains that are directly east of White Sands Missile Range. This association typically occurs on cool and steep escarpments at moderate to high elevations (1830-2410 m [6000-7900 feet]). Soils derive mostly from limestone, are moderately shallow, and range from weakly developed aridic Inceptisols to more developed and mesic Mollisols. Soils tend to be fine loamy, but can have 10 to 50% gravel and cobble content at the surface. Caliche or secondary calcium carbonate accumulations are also common. This open woodland is dominated by Pinus edulis with Juniperus monosperma as a subdominant or codominant. Scattered patches of Muhlenbergia pauciflora characterize this type along with other bunchgrasses such as Bouteloua curtipendula, along with Achnatherum scribneri and Koeleria macrantha (usually under the trees). Grass cover seldom exceeds 25%, and can occasionally range below 5%. Stands can have a diverse shrubby layer (33 species noted), but shrubs usually do not exceed 10% total cover. Cercocarpus montanus, Quercus x pauciloba, Yucca baccata, Rhus trilobata, Gutierrezia sarothrae, Nolina microcarpa, and Opuntia phaeacantha are the most consistent and abundant associates. Several forbs are possible (35+ species), but only Viguiera dentata is moderately constant.

Diagnostic Characteristics: A savanna (grassy) woodland with an overstory of Pinus edulis and Juniperus monosperma. Muhlenbergia pauciflora is usually part of the grass understory but not necessarily the dominant grass. This may be one of the drier pinyon/grass plant associations.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: As one of the more common high escarpment types, the association is often found intermixed with stands of Pinyon Pine/Shrub Live Oak PA, Pinyon Pine/Mountain Mahogany PA (Muldavin et al. 2000b), rock outcrop, and montane shrublands such as Mountain Mahogany/Wavyleaf Oak PA (Muldavin et al. 2000b). The prevalence of Muhlenbergia pauciflora is reflective of the rocky and possibly drier character of the sites. On lower slopes the association may adjoin the grassier ~Pinus edulis / Bouteloua curtipendula Open Woodland (CEGL000777)$$. Cercocarpus montanus is a fire indicator, and fire evidence present in the stands may indicate a frequent occurrence of low-intensity fires in the association''s steep, moderately productive sites. A similar type dominated by Juniperus deppeana is documented by Kennedy (1983a), and subsequently included in Moir and Carleton (1987) and USFS (1986). See Stuever and Hayden (1997b) for a comprehensive description.

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

Floristics: This open woodland is dominated by Pinus edulis with Juniperus monosperma as a subdominant or codominant. Scattered patches of Muhlenbergia pauciflora characterize this type along with other bunchgrasses such as Bouteloua curtipendula, along with Achnatherum scribneri (= Stipa scribneri) and Koeleria macrantha (usually under the trees). Grass cover seldom exceeds 25%, and can occasionally range below 5%. Stands can have a diverse shrubby layer (33 species noted), but shrubs usually do not exceed 10% total cover. Cercocarpus montanus, Quercus x pauciloba (= Quercus undulata), Yucca baccata, Rhus trilobata, Gutierrezia sarothrae, Nolina microcarpa, and Opuntia phaeacantha are the most consistent and abundant associates. Several forbs are possible (35+ species), but only Viguiera dentata is moderately constant.

Dynamics:  No Data Available
Environmental Description:  This association typically occurs on cool and steep escarpments at moderate to high elevations (1830-2410 m [6000-7900 feet]). Soils derive mostly from limestone, are moderately shallow, and range from weakly developed aridic Inceptisols to more developed and mesic Mollisols. Soils tend to be fine loamy, but can have 10 to 50% gravel and cobble content at the surface. Caliche or secondary calcium carbonate accumulations are also common.
Geographic Range: This is a major community of the San Andres and Oscura mountains of New Mexico and is also known from the Sacramento and Capitan mountains that are directly east of White Sands Missile Range.

Nations: US

States/Provinces:  NM


Confidence Level: Low - Poorly Documented

Confidence Level Comments: No Data Available
Grank: G4

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.c Mexican Pinyon - Border Pinyon - Redberry Juniper Woodland Group G200 1.B.1.Nd.1.c
Alliance A3132 Mexican Pinyon - Border Pinyon - Two-needle Pinyon / Grass Understory Woodland Alliance A3132 1.B.1.Nd.1.c
Association CEGL000785 Two-needle Pinyon / New Mexico Muhly Woodland CEGL000785 1.B.1.Nd.1.c
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Pinus edulis - Juniperus monosperma / Muhlenbergia pauciflora (Kennedy 1983b)
= Pinus edulis / Muhlenbergia pauciflora Plant Association (Kennedy 1983a)
= Pinus edulis / Muhlenbergia pauciflora (Stuever and Hayden 1997b)
= Pinyon Pine/New Mexico Muhly PA (Muldavin et al. 2000b) [(Pinus edulis/Muhlenbergia pauciflora; PINEDU/MUHPAU)]
Concept Author(s): Muldavin et al. (2000b)

Author of Description: Muldavin et al. (2000b)

Acknowledgements: No Data Available

Version Date: 10-16-18
  • 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.
  • Kennedy, K. L. 1983a. A habitat-type classification for the pinyon-juniper woodlands of the Lincoln National Forest. Unpublished thesis, New Mexico State University, Las Cruces. 87 pp.
  • Kennedy, K. L. 1983b. A habitat type classification of the pinyon-juniper woodlands of the Lincoln National Forest, New Mexico. Pages 54-61 in: W. H. Moir and L. Hendzel, technical coordinators. Proceedings of the workshop on southwestern habitat types, April 6-8, 1983, Albuquerque, New Mexico. USDA Forest Service Southwestern Region, Albuquerque, NM. 110 pp.
  • Larson, M., and W. H. Moir. 1986. Forest and woodland habitat types (plant associations) of southern New Mexico and central Arizona (north of the Mogollon Rim). USDA Forest Service, Southwestern Region, Albuquerque, NM. 76 pp.
  • Moir, W. H., and J. O. Carleton. 1987. Classification of pinyon-juniper (P-J) sites on national forests in the Southwest. Pages 216-226 in: R. L. Everett, editor. Proceedings of the Pinyon-Juniper Conference, Reno, NV, 13-16 January 1986. General Technical Report. USDA Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT. 581 pp.
  • Muldavin, E., Y. Chauvin, and G. Harper. 2000b. The vegetation of White Sands Missile Range, New Mexico: Volume I. Handbook of vegetation communities. Final report to Environmental Directorate, White Sands Missile Range. New Mexico Natural Heritage Program, University of New Mexico, Albuquerque. 195 pp. plus appendices
  • Muldavin, E., and P. Mehlhop. 1992. A preliminary classification and test vegetation map for White Sands Missile Range and San Andreas National Wildlife Refuge, New Mexico. University of New Mexico, New Mexico Natural Heritage Program.
  • 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]. 1986. Forest and woodland habitat types (plant associations) of southern New Mexico and central Arizona (north of the Mogollon Rim). USDA Forest Service, Southwestern Region, Albuquerque, NM. Second edition, 140 pp. plus insert.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.