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CEGL002148 Pinus edulis - Juniperus osteosperma / Sparse Understory Woodland

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Two-needle Pinyon - Utah Juniper / Sparse Understory Woodland

Colloquial Name: No Data Available

Hierarchy Level:  Association

Type Concept: This variable woodland association is widespread in parts of western Colorado and eastern Utah. This widespread association has total vegetation cover ranging from 10-75%. Sparsely vegetated stands (<10% total vegetation cover) composed of only trees are included in this woodland association in extremely dry, rocky portions of the Colorado Plateau. The tree canopy is dominated by Pinus edulis and Juniperus osteosperma. Both typically range from 1-35% cover with some stands having canopy cover by one species up to 50%. The tree canopy is short, usually 2-10 m tall, and open to moderately closed. Several shrub species are commonly found in this association, but they occur as widely scattered individuals, and do not form a shrub stratum. The lack of an understory may be due to high rock cover, low soil moisture, or a closed evergreen canopy of pinyon and juniper. Shrubs include Amelanchier utahensis, Artemisia tridentata, Cercocarpus montanus, Ephedra viridis, Eriogonum microthecum, Shepherdia rotundifolia, and/or Opuntia spp. The herbaceous layer is low in cover (<5%) and usually low in diversity. It is found most commonly on mid to upper slopes, though other topographic positions are possible. It occurs at elevations between 1354 and 2389 m and on all aspects. Sites range from flat to moderately steep. The ground has variable amounts of litter and often has moderate to high amounts of gravel, rocks, and exposed bedrock. Cryptogamic cover is usually low to moderate, but some sites have up to 55-65% cover. Soils are always rapidly drained to moderately well-drained. Parent materials are also highly variable and can be sandstones, shales, or limestones.

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. Environmental and physiognomic variability within this association is high. There are few consistent understory species across all parks, but that is part of the concept of this type. The general sparseness of the understory is one of the main diagnostic features. Because of the wide range of circumstances that result in a sparse understory, a lot of variability in the floristic components of the understory is allowed. It is possible that this type will be split into several associations based on environmental factors, since floristic factors are not diagnostic. On dry, rocky or slickrock sites on the Colorado Plateau, this pinyon-juniper woodland association may include stands with very open tree canopies (5-10% cover) in cases where the total vegetation cover is less than 15%, and they are considered a variation of the woodland type because of the ecological values of the trees.

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

Floristics: This widespread pinyon-juniper woodland association occurs as relatively sparse to moderately vegetated stands with total vegetation cover ranging from 10-75%. Sparsely vegetated stands (<10% total vegetation cover) composed of only trees are included as a best fit in this woodland association in extremely dry, rocky portions of the Colorado Plateau. The tree canopy is dominated by Pinus edulis and Juniperus osteosperma. Both typically range from 1-35% cover with some stands having canopy cover by one species up to 50%. The tree canopy is short, usually 2-10 m tall, and open to moderately closed. Fraxinus anomala has been observed in the canopy of some stands at Colorado National Monument but always at no more than 5% cover. Several shrub species are commonly found in this association, but they occur as widely scattered individuals or an open shrub stratum. Scattered small Pinus edulis and Juniperus osteosperma are found along with shrubs such as Amelanchier utahensis, Artemisia bigelovii, Artemisia nova, Artemisia tridentata, Cercocarpus montanus, Chrysothamnus viscidiflorus, Coleogyne ramosissima, Ephedra viridis, Ericameria nauseosa, Eriogonum microthecum, Gutierrezia sarothrae, Mahonia fremontii, Opuntia fragilis, Opuntia polyacantha, Purshia tridentata, Shepherdia rotundifolia, and Symphoricarpos longiflorus. The herbaceous layer is low in cover (<5%) and usually low in diversity. Achnatherum hymenoides, Bouteloua gracilis, Bromus tectorum, Poa fendleriana, and Pleuraphis jamesii are common graminoids. Forbs are not abundant, but typical species include Descurainia pinnata, Cryptantha flava, Cordylanthus wrightii, Lepidium montanum, Petradoria pumila, and Tetraneuris acaulis. The sparsest sites have only trace vascular understory cover, but often high cover of biological soil crusts.

Dynamics:  The variability of this association is due to the range of circumstances in which it can occur. Some stands have a sparse understory because the substrate has poor water-holding capacity (e.g., shale-derived), or because the surface is nearly completely covered by rock or bedrock. Other stands may have low understory cover because the canopy is nearly closed and herbaceous and shrub species cannot exist in the conditions of low light and available moisture that characterize these stands.
Environmental Description:  This woodland association is found most commonly on mid to upper slopes, on valley floors, plateaus, colluvial slopes, hills, canyon rims, canyon sides, mesas, plains, and benches. It has been sampled at elevations between 1354 and 2389 m and on all aspects. Sites range from flat to moderately steep (0-25°). The ground has variable amounts of litter and often has moderate to high amounts of gravel, rocks, and exposed bedrock. Cryptogamic cover is usually low to moderate, but some sites have up to 55-65% cover. Soils vary in texture and can be loamy sand, silts, loams or silty clay but are always rapidly drained to moderately well-drained. Parent materials are also highly variable and can be sandstones, shales, limestones, among others.
Geographic Range: This association is known from the Colorado Plateau and Southern Rocky Mountains in northern Arizona, southern Utah, and western Colorado.

Nations: US

States/Provinces:  AZ, CO, UT


Confidence Level: High

Confidence Level Comments: No Data Available
Grank: G5

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.2 Cool Temperate Forest & Woodland Formation F008 1.B.2
Division 1.B.2.Nc Western North American Pinyon - Juniper Woodland & Scrub Division D010 1.B.2.Nc
Macrogroup 1.B.2.Nc.1 Singleleaf Pinyon - Utah Juniper - Western Juniper Intermountain Woodland Macrogroup M896 1.B.2.Nc.1
Group 1.B.2.Nc.1.a Two-needle Pinyon - Utah Juniper Woodland Group G900 1.B.2.Nc.1.a
Alliance A3573 Two-needle Pinyon - Utah Juniper Colorado Plateau Shrubby Open Woodland Alliance A3573 1.B.2.Nc.1.a
Association CEGL002148 Two-needle Pinyon - Utah Juniper / Sparse Understory Woodland CEGL002148 1.B.2.Nc.1.a
Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Pinus edulis - Juniperus osteosperma / Sparse Understory Woodland (Von Loh et al. 2008)
Concept Author(s): Von Loh et al. (2008)

Author of Description: J. Drake, J. Coles, K.A. Schulz and G. Kittel

Acknowledgements: No Data Available

Version Date: 07-13-16
  • 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.
  • Coles, J., A. Tendick, J. Von Loh, G. Bradshaw, G. Manis, A. Wight, G. Wakefield, and A. Evenden. 2010. Vegetation classification and mapping project report, Black Canyon of the Gunnison National Park. Natural Resource Technical Report NPS/NCPN/NRTR--2010/361. National Park Service, Fort Collins, CO.
  • Coles, J., D. Cogan, D. Salas, A. Wight, G. Wakefield, J. Von Loh, and A. Evenden. 2008a. Vegetation classification and mapping project report, Dinosaur National Monument. Natural Resource Technical Report NPS/NCPN/NRTR-2008/112. National Park Service, Fort Collins, CO. 814 pp.
  • Coles, J., J. Von Loh, A. Evenden, G. Manis, G. Wakefield. and A. Wight. 2008c. Vegetation classification and mapping project report, Natural Bridges National Monument. Natural Resource Technical Report NPS/NCPN/NRTR--2008/077. National Park Service, Fort Collins, CO. 390 pp.
  • Kearsley, M. J. C., K. Green, M. Tukman, M. Reid, M. Hall, T. J. Ayers, and K. Christie. 2015. Grand Canyon National Park-Grand Canyon / Parashant National Monument vegetation classification and mapping project. Natural Resource Report NPS/GRCA/NRR--2015/913. National Park Service, Fort Collins, CO. 75 pp. plus appendices.
  • Reid, M. S., and M. E. Hall. 2010. Vegetation classification of Grand Canyon National Park. Draft report submitted to National Park Service, Fort Collins, CO.
  • 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., and C. Bolen. 2010b. Vegetation classification and distribution mapping report: Hubbell Trading Post National Historic Site. Natural Resource Technical Report NPS/SCPN/NRTR-2010/301. National Park Service, Fort Collins, CO. 35 pp.
  • Tendick, A., G. Kittel, J. Von Loh, P. Williams, D. Cogan, J. Coles, A. Wight, G. Wakefield, and A. Evenden. 2011b. Vegetation classification and mapping project report, Bryce Canyon National Park. Natural Resource Technical Report NPS/NCPN/NRTR--2011/442. National Park Service, Fort Collins, CO.
  • 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. Coles, P. Williams, G. Bradshaw, G. Manis, A. Wight, G. Wakefield, and A. Evenden. 2010. Vegetation classification and mapping project report, Curecanti National Recreation Area. Natural Resource Technical Report NPS/NCPN/NRTR--2010/408. National Park Service, Fort Collins, CO. 797 pp.
  • 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.
  • Thomas, K. A., M. L. McTeague, L. Ogden, K. Schulz, T. Fancher, R. Waltermire, and A. Cully. 2010. Vegetation classification and distribution mapping report: Canyon de Chelly National Monument. National Resource Technical Report NPS/SCPN/NRTR-2010/306. National Park Service, Fort Collins, CO. 338 pp.
  • Thomas, K. A., M. L. McTeague, L. Ogden, M. L. Floyd, K. Schulz, B. Friesen, T. Fancher, R. Waltermire, and A. Cully. 2009b. Vegetation classification and distribution mapping report: Mesa Verde National Park. Natural Resource Report NPS/SCPN/NRR--2009/112. National Park Service, Fort Collins, CO. 352 pp.
  • Von Loh, J., G. Wakefield, A. Wight, A. Evenden, and J. Coles. 2008. Vegetation classification and mapping project report, Hovenweep National Monument. Natural Resource Report NPS/NCPN/NRTR--2008/092. National Park Service, Fort Collins, CO. 328 pp.
  • Von Loh, J., K. Landgraf, A. Evenden, T. Owens, S. Blauer, and M. Reid. 2007. Vegetation classification and mapping project report, Colorado National Monument. Natural Resource Report NPS/NCPN/NRTR--2007/061. National Park Service, Fort Collins, CO. 564 pp.
  • Western Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Boulder, CO.