The Rocky Mountain ponderosa pine forest is a plant community at an elevation of in the Rocky Mountains. It is an important temperate coniferous forest ecoregion, including some endemic wildlife and grass species that are only found in this ponderosa pine (''Pinus ponderosa'') habitat.

Ecology

Ponderosa pine occurs as a mid- seral species and Douglas-fir is the climax forest in the Rocky Mountains. Quaking aspen and lodgepole pine are early-seral associates of ponderosa pine on these sites. Ground-level vegetation includes ninebark (''

Physocarpus ''Physocarpus'', commonly called ninebark, is a genus of flowering plants in the family Rosaceae, native to North America (most species) and northeastern Asia (one species). Description ''Physocarpus'' are deciduous shrubs with peeling bark

'' spp.), elk sedge (''

Carex geyeri ''Carex geyeri'' is a species of sedge known by the common names Geyer's sedge and elk sedge. It is native to western North America from British Columbia to California to Colorado, where it grows in dry areas in mountain meadows, grasslands, and ...

''), and pine grass (''

Calamagrostis rubescens ''Calamagrostis rubescens'' is a species of grass known by the common name pinegrass. Distribution It is native to western North America, including Canada from British Columbia to Manitoba and the United States from California to Colorado. It ca ...

''). These species, in particular, exemplify aggressive survivors after disturbance (e.g., fire, mechanical site preparation) and are strong competitors for light and nutrients which compete with ponderosa pine seedlings.

Climate

The pure stands of Rocky Mountain ponderosa pine forest receive about of annual precipitation. In the northern Rockies, about 40-50% falls in April through September, while in the southern Rockies, about 66-75% falls during these months. During these months there is high evapotranspiration because ''Populus tremuloides'' intercept a lot of the precipitation. The average temperature for this community is, on average, warmer than other conifer communities studied. The average temperature is approximately , creating 50-100 frost-free days per year.

Wildlife

The ponderosa pine forest, unlike the lodgepole pine and spruce/fir forests, supports numerous mammal species including

Abert's squirrel Abert's squirrel or the tassel-eared squirrel (''Sciurus aberti'') is a tree squirrel in the genus ''Sciurus'' native to the southern Rocky Mountains from the United States to the northern Sierra Madre Occidental of Mexico, with concentrations fo ...

(''Sciurus aberti''), which only lives in ponderosa pine communities. ''S. aberti'' usually prefers a cluster of trees and feeds on the seeds of the cones. ''S. aberti'' has also adapted to the chemicals ponderosa pine produces for protection by targeting the trees that have lowered chemical levels.

Pygmy nuthatch The pygmy nuthatch (''Sitta pygmaea'') is a tiny songbird, about long and about 10 grams in weight. Description Measurements: * Length: * Weight: * Wingspan: It ranges from southern British Columbia south through various discontinuo ...

es (''Sitta pygmaea'') are also adapted to ponderosa pine woodlands. Another species that can be supported by ponderosa pine is the

Colorado chipmunk The Colorado chipmunk (''Neotamias quadrivittatus'') is a species of chipmunk in the squirrel family Sciuridae. It is Endemism, endemic to Colorado, Utah, Arizona and New Mexico in the United States. Description It can be found most often in co ...

(''Tamias quadrivitattus''). ''T. quadrivitattus'' helps spread the seeds of the ponderosa pine by spreading out and burying its caches. This results in the seeds being further from the trees and better germination rates. This community also hosts the gopher snake (''Pituophis catenifera''), which burrows into gopher holes. Also, ponderosa pine provides habitat for the

cougar The cougar (''Puma concolor'') is a large Felidae, cat native to the Americas. Its Species distribution, range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mamm ...

(''Puma concolor'') and the

bobcat The bobcat (''Lynx rufus''), also known as the red lynx, is a medium-sized cat native to North America. It ranges from southern Canada through most of the contiguous United States to Oaxaca in Mexico. It is listed as Least Concern on the IUC ...

(''Lynx rufus'') as well as birds as

western tanager The western tanager (''Piranga ludoviciana''), is a medium-sized American songbird. Formerly placed in the tanager family (Thraupidae), other members of its genus and it are classified in the cardinal family (Cardinalidae). The species's plumag ...

(''Piranga ludoviciana''), wild turkey (''Meleagris gallopavo''), mountain bluebird (''Sialia currucoides''), and

white-breasted nuthatch The white-breasted nuthatch (''Sitta carolinensis'') is a species of bird in the nuthatch family Sittidae. It is a medium-sized nuthatch, measuring approximately in length. Coloration varies somewhat along the species' range, but the are lig ...

(''Sitta carolinensis''). The species present in this area affect the vegetation and provide aesthetic value for the people who use this area recreationally. There is less canopy cover in a ponderosa pine community compared to a lodgepole pine ('' Pinus contorta'') and spruce/fir community, resulting in more grasses, forbs, and shrubs. The high species richness of the understory in this community makes it preferred by grazing animals such as elk ('' Cervus elaphus''), deer ('' Odocoileus hemionus''), and moose ('' Alces alces'').

Wildfire

In the northern Rocky Mountains of Idaho and western Montana, dry settings of ponderosa pine forests historically burned by low severity surface fires that did not kill overstory trees at 15 to 23 year mean return intervals. Cultural burning by Native Americans augmented and even dominated burning in several locations.

Recreation

The ponderosa pine forest is a favored location for summer cabins and is often easily accessed. Much camping and four-wheel driving happens during the summer in the area also. Hunting is favored in the ponderosa pine forest because the trees are more spaced out than other conifer forests making for better range of sight, and the forest is lower and has less snow.

References