Physiognomy and Structure: No Data Available

Floristics: Within Salinas Pueblo Missions National Monument in central New Mexico, this Madrean woodland/savanna is characterized by an open canopy of mature Juniperus monosperma; saplings or seedlings are also common. Occasionally seedling or sapling Pinus edulis can be present, commonly under the canopy of Juniperus monosperma. The understory is characteristically grassy and dominated by Muhlenbergia setifolia along with Bouteloua gracilis. Bouteloua eriopoda, Bouteloua hirsuta, Aristida purpurea, and Bouteloua curtipendula may also be common, but not dominant. Forbs and shrubs are scattered and variable and may include Physalis hederifolia var. fendleri, Ipomopsis aggregata, Melampodium leucanthum, Dalea formosa, and Gutierrezia sarothrae. Within White Sands Missile Range in south-central New Mexico, this woodland association is distinguished by a very open to moderately open tree canopy dominated by Juniperus monosperma. Scattered Pinus edulis may also be present. The grassy understory is dominated by Muhlenbergia setifolia that is abundant to luxuriant. Shrubs are present but low in cover and may include a wide variety of species; Nolina microcarpa, Opuntia phaeacantha, Rhus trilobata, and Yucca baccata are constant associates. The herbaceous layer is also highly diverse. Aristida purpurea, Bouteloua curtipendula, and Bouteloua gracilis are often present, though at much lower cover than Muhlenbergia setifolia. Common forb species, although scarce, include Lesquerella fendleri and Melampodium leucanthum, (Muldavin et al. 2000b).

Dynamics:  Juniperus monosperma is extremely drought-tolerant. It is also non-sprouting and may be killed by fire (Wright et al. 1979). The effect of fire on a stand is largely dependent on the tree height and density, fine fuel load on the ground, weather conditions, and season (Dwyer and Pieper 1967, Wright et al. 1979). Trees are more vulnerable in open stands where fires frequently occur in the spring, the relative humidity is low, wind speeds are over 10-20 mph, and there is adequate fine fuels to carry fire (Wright et al. 1979, Fischer and Bradley 1987). Under other conditions, burns tend to be spotty with low tree mortality. Large trees are generally not killed unless fine fuels, such as tumbleweeds, have accumulated beneath the tree to provide ladder fuels for the fire to reach the crown. Closed-canopy stands rarely burn because they typically do not have enough understory or wind to carry a fire. Altered fire regimes, cutting trees for fencing, and improper grazing by livestock have significant impacts on the quality of sites. Grazing by livestock can modify the fire regime by removing the fine fuels that carry fire. Juniperus monosperma invasion into grasslands has occurred in places. Control efforts by chaining and prescribed burning have mixed results. More study is needed to understand and manage these woodlands ecologically.