Nearctic Oak-Juniper Woodland - Code: Ne6A

Oak Juniper Woodland is a dry and patchy, oak and juniper savanna located on steep and rocky limestone or dolomitic soils of the Texas Hill Country and a few other outlying pockets in the sc. United States and n. Mexico. The structure of the habitat varies with topography but comprises short grasses with scattered small trees, low shrubs, and rocky outcroppings. Occurring in a semiarid subtropical zone, the region has a highly seasonal climate, with moderately cold winters and hot summers. Typical winter low temperatures are 25–35°F (⎻4–2°C), and average summer highs are around 90–95°F (29–32°C). The region receives about 30 in. (750mm) of annual precipitation, with peak precipitation falling in May and June. 

The Oak Juniper Woodlands habitat is comprised of two major subtypes. The first, Edwards Plateau Oak Scrubland is an open, shrubby savanna dominated by small Ashe Juniper (Juniperus ashei), Eastern Red Cedar (Juniperus virginiana), Redberry Juniper (Juniperus pinchotti). Small scrubby oaks are also present but rarely dominate. Canopy trees here rarely surpass 20ft (6m) in height and canopy cover is usually less than 30%. This subtype also has a well-developed shrub and understory layer. The mid-story of these savannas is a smattering of sapling canopy trees and small shrubs, including Texas Persimmon (Diospyros texana), Agarito (Mahonia trifoliata), Texas Mountain-laurel (Dermatophyllum secundiflorum), Honey Mesquite (Prosopis glandulosa), and pricklypears (Opuntia sp.). While generally sparse, the density of the shrub layer (particularly Honey Mesquite) can increase with overgrazing, choking out the normally dominant understory of Little Bluestem (Schyzacharium scoparum), Side-oats Grama (Bouteloua curtipendula), Texas Wintergrass (Nassella leucotricha), Curly Mesquite Grass (Muhlenbergia setifolia), and buffalograsses (Bouteloua sp.). This subtype naturally experiences frequent low intensity fires that maintain the open-grassy structure. 

The second subtype, Edwards Plateau Oak-Juniper Woodland has a much more forested feel. Often occurring in dense copses called mottes, this subtype is strongly dominated by a variety of oaks. Post (Quercus stellata), Blackjack (Q. marilandica), Lacey Oak (Q. laceyi) and Texas Oaks (Q. buckleyi), Cedar elm (Ulmus crassifolia), Hackberry (Celtis sp.) and especially Plateau Live Oak (Q. fusiformis), are the primary canopy trees. Juniper and cedar species are regularly present but rarely dominant and often occur as a mid-canopy or shrub layer. This is still a relatively short woodland with most canopy trees growing to a height of only 30–40 ft. (10–12m). Canopy cover ranges from 30-70%. The shrub and understory layers are generally poorly developed but contain similar species to Edwards Plateau Oak Scrubland. In this subtype fires are naturally less frequent and more intense than in scrubland. These fires clear out shrubs while leaving the canopy intact.