MAPPING UNIT ATTRIBUTE CODE: 42010

MAPPING UNIT NAME: Ponderosa pine type.

DOMINANT SPECIES: Ponderosa pine (Pinus ponderosa)

DESCRIPTION: Ponderosa pine dominated forest or woodland that is not
significantly affected by logging. Canopy closure may vary from 26-100%.

DISTRIBUTION: Found throughout the state of Colorado. East of the
continental divide from the Colorado - Wyoming border northward, the low
elevation habitat of ponderosa pine occurs only along the far eastern fringe
of the Rocky Mountain region (Black Hills, Bighorn Mountains, Laramie Range
and rocky outcrops in between).

ELEVATION RANGE: 1524-2744m (5000-9000')

DIAGNOSTIC SPECIES: Pinus ponderosa

NOTES: Near the upper elevation limit, P. ponderosa increases in density to
form well developed forests, and may be successional to Douglas fir. At the
lower elevation limits, this type grades into pinyon juniper woodland or
encinal (oak shrub), and where pinyon - juniper is absent, the type becomes
progressively more open until only scattered individuals remain in the most
rocky areas (Peet, 1988). The grass understory is usually highly flammable,
leading to many fires in this type, and probably has the highest fire
frequency of any Rocky Mountain forest type. Along the Front Range, this
type may have a well developed Quercus gambelii or other shrub understory
in southern Colorado, but further north, shrubs are much reduced and the
understory is more grassy (Peet, 1978).

Habitat and community types identified for Pinus ponderosa include, on
warm very dry sites, Cercocarpus montanus, and Oryzopsis hymenoides (on
sand hills). On warm to hot, dry sites it is associated with Festuca
arizonica. On warm dry sites, P. ponderosa can be associated with
Arctostaphylos uva ursi, Artemisia tridentata, Purshia tridentata, Quercus
gambelii, Ribes inerme (in scree situations), Muhlenbergia montana, and
Carex rossii. On cool to warm moist sites, it is found with Poa pratensis
(often riparian situations). Common tree associates are J. monosperma, P.
edulis, P. menziesii, J. scopulorum, P. flexilis, P. angustifolia, A. negundo,
and A. tenuifolia (Alexander, 1987).