Physiognomy and Structure: This group encompasses savanna that has widely spaced, short (2-10 m tall), mature (>150 years old) juniper trees and occasionally a Pinus edulis tree. The open to dense herbaceous layer typically dominates the vegetation and is composed of perennial grasses. These savannas have inclusions of denser juniper stands, especially near rock outcrops, that are somewhat fire-protected, and have greatly expanded into adjacent plains during the last century. Older established stands have widely species large, mature, rounded-crown trees, whereas more recent invasive juniper savanna stands are characterized by younger, shorter (<3 m tall, pointed-crown juniper trees.

Floristics: This group is best described as a savanna that has widely spaced, mature (>150 years old) juniper trees with lush perennial grasses in between trees, but may have inclusions (patches) of denser juniper woodlands. Juniperus monosperma is the dominant tree (2-10 m tall) with an occasional Pinus edulis tree. Juniperus scopulorum may dominate or codominate at higher elevations. Grass species are similar to those found in Shortgrass Prairie in the western Great Plains. Bouteloua gracilis, Bouteloua curtipendula, and Pleuraphis jamesii are most common, with Hesperostipa comata, Koeleria macrantha, Lycurus phleoides and Muhlenbergia torreyi often present. Bouteloua eriopoda is a more common grass in the southern extent, and Andropogon hallii and Muhlenbergia pungens are characteristic of deep sandy sites. Shrubs are poorly represented or absent; the ruderal subshrub Gutierrezia sarothrae and succulents such as Cylindropuntia imbricata, Opuntia phaeacantha, Opuntia polyacantha, Rhus trilobata, Yucca baccata, and Yucca glauca are the most frequent. Forbs such as Astragalus spp., Cryptantha cinerea var. jamesii (= Cryptantha jamesii), Eriogonum jamesii, Erigeron divergens, Hymenopappus filifolius, Ipomopsis multiflora, Mentzelia spp., and Penstemon spp. are also common.

Dynamics:  Juniperus monosperma is a long-lived, slow-growing, drought-tolerant small tree (3-12 m in height) that also occurs as a tall shrub (Johnson 2002). It is more drought-tolerant than Pinus edulis and often occurs without pinyon on more xeric, lower elevation sites (Johnson 2002). It is also non-sprouting and may be killed by fire (Wright et al. 1979). Juniper stands at cooler, higher elevation sites typically occur on xeric microsites that are too arid for pinyon or on post-disturbance sites such as where extended drought or ips beetle (Ips confusus) epidemics have eliminated pinyon from mixed pinyon-juniper stands. In this situation junipers and shrubs may act as nurse plants providing shade for pinyon germination and re-establishment, converting a juniper woodland to pinyon-juniper woodland.

Within a given region, the density of trees, both historically and currently, is strongly related to topo-edaphic gradients. Less steep sites, especially those with finer-textured soils, are where savannas, grasslands, and shrub-steppes have occurred in the past. Juniper stands on these gentler slopes may have been larger but more savanna-like, with very open upper canopy and high grass production. Expansion of juniper into previously non-wooded areas occurred prior to European settlement on some sites, although this expansion may have been more extensive in the 20th century versus the previous. However, loss of juniper from marginal sites also occurred historically and recently in some areas (Romme et al. 2009). Especially in areas in which trees were historically rare or absent, there have been type conversions such that the historical condition is unidentifiable/replaced today. An important result of expansion into formerly non-wooded areas in many regions is that formerly heterogeneous mosaics of small patches of woodland, shrubland, and grassland are becoming more homogeneous as trees become established in the shrubland and grassland patches (Romme et al. 2009).