Oak/pinyon/juniper woodland and grassland on mountains influenced by limestone and associated rocks

91% steep — most of the flatter ground is around Brush Corral.

Ranging between 6000 and 3500 feet (1850 to 1100 meters), this EU holds Emory, Arizona and blue oak, juniper, and manzanita on moist slopes, while dry slopes are dominated by bunchgrasses and a mix of sotal (Dasylirion wheeleri) and beargrass. Tree/shrub cover can reach 25-39% at the toe of north slopes, and less than 4% on south slopes. Located on the north and east side of the Catalinas, its geology is a confusion of strata similar to the “0ak-juniper-pinyon on mixed rocks” EU, except this EU reaches lower and holds more limestone and shale.

Slopes are typically steep, with 91% of the EU exceeding 18% slope. However, there are around 1000 acres of low rolling hills in upper Buehman Canyon in the vicinity of the now-vanished Brush Corral Ranger Station. This is the only part of the EU where mesquite is common.

Above, Catalinas, September 2008, 5900 ft., the view NE across the shadows of upper Buehman Canyon to the distant rocky summit of Evans Mountain - all of which falls into this EU. Trees on this south-facing slope are juniper, blue and Emory oak, growing amid sotol, beargrass, and bunchgrasses. This area burned in either the Bullock or Aspen fire.

Above, Catalinas, October 2008, 4400 feet, looking south from a limestone and shale slope above Alder Canyon. The foreground is dominated by a flowering snakeweed (Gutierrezia sarothrae), but the dominance is shared with Mortonia scabrella (saddlebush, or sandpaper bush) and Arizona oak, combining for 15-24% cover. Mountain mahogany and manzanita are common, too. This area was recently burned lightly.

Above, Catalinas, looking west from near Peppersauce Canyon, 27 Oct 2009, 4750 feet. On this south-facing limestone slope the dominant plants are bunchgrasses like tanglehead and sideoats, pricky pear cactus, and fairy duster (Calliandra eriophylla). The shrub with yellow flowers, Tecoma stans, is surprising common, with 1-4% cover.

Desired Conditions

Desired conditions are adapted from Madrean encinal woodland, mid-scale desired condition statements in March 2010 Coronado National Forest planning documents.

The size and number of patches of dense trees varies depending mostly on aspect, and to a lesser degree disturbance, soil type, and site productivity. Patch sizes vary, but are mostly tens of acres. Grasses, forbs, shrubs, tree litter, and small trees provide fuel for the natural fire regime with a greater proportion of the ground cover as grasses and forbs as opposed to litter. Vegetation structure in the wildland urban interface (WUI) has a broad mix of different landscapes, such as open areas and scattered groups or clumps of woodland tree species.

Historic Mean Fire Return Interval (Schussman et al. 2006 literature review)

2.5-10 years for Madrean encinal woodland

Primary treatment options (estimated representative project size range):

• Wildland fire: Prescribed fire and/or wildfire to maintain openings, reduce ground fuels, and site prep (1,000 to 30,000 acres per project)
• Fuelwood sales (smaller diameter, including aspens) to reduce fuel loading (up to 300 acres per project)
• First-entry mechanical treatments to prepare for fire reintroduction (mastication/crushing) (up to 2,500 acres per project)

Supplemental treatment options (estimated representative project size range):

• Thinning around developments for safety-related fuel reduction (up to 500 acres per project)
• Herbicide treatment for exotics (cheatgrass) and shrub management to maintain openings (up to 1,000 acres per project)

Other considerations

May be wilderness considerations with treatments.

Other Vegetation Classifications: