Name:
Pinus ponderosa / Schizachyrium scoparium Open Woodland
Reference:
NatureServe Biotics 2019
Description:
This ponderosa pine / little bluestem association is a dry woodland found in the Great Plains of the United States extending west to the mountains of New Mexico, Colorado and Wyoming. In the Great Plains, it usually occurs on south- and west-facing slopes of hills, rocky breaks, and watercourses. In the western portion of its range, this association occurs at mid-elevation, ranging from 1780 and 2430 m (5840-7970 feet), on sites with low to high solar exposure that increases with elevation. Stands occur on gentle slopes of mesatops and shoulders (5-10%) and occasionally on steep (40%) upper canyon slopes. Soils are primarily mapped as well-developed Mollisols derived from pumice slope alluvium, or occasionally as fine-textured Alfisols derived from mixed eolian, and rarely, Aridisols derived from colluvial basalts. At El Malpais National Monument in western New Mexico, it occurs on collapse features and on the tops of very gently rolling lava plateaus. The topography varies from fractured basalt and rocky mounds to flatter areas with some soil development. Substrates are derived from volcanic basalt, and ground surface is typically dominated by rock with litter well-represented. Elsewhere, the ground surface is typically characterized by scattered bunchgrasses amid pumice gravel and litter. In the Great Plains, the overstory is dominated by <i>Pinus ponderosa</i>. <i>Juniperus scopulorum</i> may often be present, but typically only as scattered individuals. The shrub layer is composed of species such as <i>Juniperus scopulorum, Rhus trilobata</i>, and <i>Symphoricarpos</i> spp. <i>Schizachyrium scoparium</i> is the most abundant graminoid, often accompanied by <i>Andropogon gerardii, Bouteloua curtipendula, Bouteloua gracilis, Carex inops ssp. heliophila, Carex siccata, Hesperostipa comata, Pascopyrum smithii</i>, and <i>Poa pratensis</i>. Common forbs include <i>Achillea millefolium, Phlox hoodii</i>, and <i>Allium</i> spp. In New Mexico, this open woodland / savanna is dominated by <i>Pinus ponderosa</i> with canopies that range from 10-30% cover with other tree species (<i>Pinus edulis, Pseudotsuga menziesii, Quercus gambelii</i>) rare or incidental. <i>Pinus ponderosa</i> seedling and sapling reproduction is typically present. <i>Juniperus monosperma</i> and <i>Pinus edulis</i> saplings are also occasionally present in the subcanopy. Shrubs are usually poorly represented (occasionally <i>Robinia neomexicana</i> or <i>Ribes cereum</i> are well-represented). Stands are distinctively grassy (cover can reach 30%). Dominant graminoids include prairie species <i>Schizachyrium scoparium</i> along with <i>Muhlenbergia montana, Poa fendleriana</i>, and <i>Elymus elymoides</i>. <i>Bouteloua gracilis</i>, while often present, is clearly subdominant. Numerous forb species may be common to well-represented and are variable from stand to stand.
Accession Code:
urn:lsid:vegbank.org:commConcept:29110-{A4FE9548-01EB-40E0-996C-511BDECA87E2}
Plot-observations of this Community Concept:
2
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