Madrean Upper Montane Conifer-Oak Forest and Woodland

Description

The Madrean Upper Montane Conifer-Oak Forest and Woodland ecosystem is in the Chiricahua high country, from 6800 to 9000 feet. Like the rest of the summit region, it sits atop volcanic and sub-volcanic (almost but not quite extrusive) rocks, middle Miocene to Oligocene (15 to 38 Mya). However, it is considerably steeper than the ecosystems that are situated in higher terrain. While 6-8% of the aspen/spruce and the Rocky Mt. mixed conifer ecosystems are on gentle terrain of <18% slope, only 1% of this ecosystem is similarly sited. In other respects, this ecosystem is, as stated in The National Vegetation Classification System (NVCS) description, "similar to Southern Rocky Mountain Dry-Mesic Montane Mixed Conifer Forest and Woodland, which typically lacks Madrean elements."

The vegetation is a mosaic of Douglas fir (Psuedotsuga menziesii) dominated forest on mesic slopes with Madrean oaks (Quercus hypoleucoides, Q. reticulata/rugosa, and Q. arizonica) dominating xeric slopes. White fir (Abies concolor) and Pinus ponderosa, P. arizonica, P. leiophylla (Chihuahuan Pine), P. engelmannii (Apache Pine), and P. strobiformis can be common but are generally not co-dominants. Similar trees make up the lower elevation Madrean Lower Montane Pine-Oak Forest and Woodland, but with this key difference: the Upper Montane conifer-oak is more than 50% Douglas Fir and big pines, while the Lower Montane pine-oak is more than 50% oaks. Pinyon pine and alligator juniper can pop up in rocky areas, but are typically not dominants.

The Madrean Upper Montane Conifer-Oak Forest and Woodland ecosystem is not mapped by Landfire’s EVT, which instead opts to transition from the higher Southern Rocky Mountain Dry-Mesic Montane Mixed Conifer Forest and Woodland to the Madrean Lower Montane Pine-Oak Forest and Woodland. This is possibly because the NVCS description of the Upper Montane makes no mention of the pines. Hence, the ecosystem as mapped here, with pines, is a significant departure from the NVCS description.

Other Vegetation Classifications

The Madrean Upper Montane Conifer-Oak Forest and Woodland ecosystem includes elements of several vegetation types mapped or described in other classification schemes. In each of the six schemes referred to below, the * symbol marks the vegetation type most similar to the Madrean Upper Montane Conifer-Oak Forest and Woodland.

And what is meant by ‘most similar’? For the USFS Plant "Habitat Type" (Potential Association), the USFS "Potential Natural Vegetation Type" (PNVT), and the Brown, Lowe, and Pase "Biome", the * symbol denotes the best fit based on the description of the Habitat Type, PNVT, or Biome. For the Landfire, ReGap, and USFS mid-scale classifications, which are presently mapped at a 30 meter resolution and were used in creating the map, the * symbol denotes the classification that was most commonly attributed within Madrean Upper Montane Conifer-Oak Forest and Woodland, as mapped in this effort.

Landfire Existing Vegetation Type (EVT)
NOTE: Landfire does not recognize the Madrean Upper Montane Conifer-Oak Forest and Woodland in the study area. Instead, Landfire maps the following:
Madrean Lower Montane Pine-Oak Forest and Woodland *
Southern Rocky Mountain Dry-Mesic Montane Mixed Conifer Forest and Woodland
Rocky Mountain Montane Riparian System
Southern Rocky Mountain Montane-Subalpine Grassland (burned areas, Snowshed Peak)

USFS Mid-scale Dominance Type
Upper Evergreen Forest Tree Mix (PIPO_PSME, PSME, TETX) *
Ponderosa Pine (PIPO)

USFS Plant Habitat Type (Potential Association)
Douglas fir/screwleaf muhly (PSME/MUVI)*(mesic)
Ponderosa pine/screwleaf muhly (PIPO/MUVI) *(xeric)
Douglas fir/Gambel oak (PSME/QUGA)
Ponderosa pine/Gambel oak (PIPO/QUGA)
White fir/Gambel oak (ABCO/QUGA)
White fir/Rocky Mt. Maple (ABCO/ACGL)
White fir/Oregon grape (ABCO/BERE)