• GENERAL DISTRIBUTION
• ECOSYSTEMS
• STATES
• BLM PHYSIOGRAPHIC REGIONS
• KUCHLER PLANT ASSOCIATIONS
• SAF COVER TYPES
• SRM (RANGELAND) COVER TYPES
• HABITAT TYPES AND PLANT COMMUNITIES

GENERAL DISTRIBUTION:

Interior ponderosa pine's general distribution is from the eastern slope of the northern Rocky Mountains in Montana east to central Nebraska and Kansas and south to eastern Nevada, western Texas, and Mexico. The distribution continues south from Texas into Coahuila, Tamaulipas, and San Luis Potos [79,80,271]. However, interior ponderosa pine is not a geographically distinct taxon [161]. There is a broad zone of intergradation between interior and Pacific ponderosa pines in southeastern Idaho and on both sides of the Continental Divide in Montana and Wyoming [36,71,95,232,233]. Interior ponderosa x Arizona pine intergrades occur in southeastern Arizona, southeastern New Mexico, and Mexico [36,95,114,233].  On sky islands of southeastern Arizona, interior ponderosa pine mostly occurs above 7,000 feet (2100 m) elevation. A transition zone of intergraded interior ponderosa pine × Arizona pine occurs between 500 and 7000 feet (150-2100 m) [95].

ECOSYSTEMS [120]:

STATES:

BLM PHYSIOGRAPHIC REGIONS [38]:

KUCHLER [187] PLANT ASSOCIATIONS:

SAF COVER TYPES [104]:

SRM (RANGELAND) COVER TYPES [263]:

HABITAT TYPES AND PLANT COMMUNITIES:

MT: In central Montana the interior ponderosa pine type merges into plains grassland at lower elevations and limber pine at higher elevations. Limber pine, Rocky Mountain Douglas-fir, and Rocky Mountain juniper (Juniperus scopulorum) are common overstory associates. Plains grassland species include blue grama (Bouteloua gracilis), sideoats grama (B. curtipendula), and prairie Junegrass (Koeleria macrantha). Western snowberry (Symphoricarpos occidentalis) and skunkbush sumac (Rhus trilobata) are common shrub associates. Soapweed yucca (Yucca glauca), pygmy prickly-pear (Opuntia fragilis), and plains prickly-pear (O. polyacantha) occur on the driest sites [14,227]. Rocky Mountain juniper, bluebunch wheatgrass  (Pseudoroegneria spicata), and longleaf wormwood (Artemisia longifolia) are dominant species in interior ponderosa pine of the Missouri River Breaks [206].

Interior ponderosa pine is the only forest tree in southeastern Montana, where it forms several diverse habitats. On dry sites it supports an understory of plains grassland species such as big bluestem (Andropogon gerardii var. gerardii), little bluestem (Schizachyrium scoparium), and blue grama, and of mountain grassland species such as bluebunch wheatgrass and elk sedge (Carex geyeri). Understories are typically dense on wetter sites, and include species characteristic of Pacific ponderosa pine forests to the west. Russet buffaloberry (Shepherdia canadensis), bearberry (Arctostaphylos uva-ursi), twinflower (Linnaea borealis), and heartleaf arnica (Arnica cordifolia) are common wet-site associates [14,227].

WY: Interior ponderosa pine is usually the only tree at lower timberline in the Bighorn Mountains. Shrubs or grasses may dominate the understory. The most common understory dominants are bluebunch wheatgrass, Idaho fescue, white spirea (Spiraea betulifolia), and mountain ninebark (Physocarpus monogynus) [162]. Interior ponderosa pine communities are uncommon in southeastern Wyoming. Where they occur, elk sedge most commonly dominates the understory. Ross' sedge (C. rossii) and bearberry are occasional understory dominants. Common graminoids and forbs include prairie Junegrass, spike fescue (Leucopoa kingii), western yarrow (Achillea millefolium), and heartleaf arnica [8].

White spruce (Picea glauca) may co-occur with interior ponderosa pine in the Black Hills of Wyoming and South Dakota. Bur oak (Quercus macrocarpa), quaking aspen (Populus tremuloides), and paper birch (Betula papyrifera) are overstory associates [50].

Dakotas: Interior ponderosa pine understories in the Black Hills of South Dakota are usually dominated by shrubs including common juniper (Juniperus communis), russet buffaloberry, common snowberry (Symphoricarpos albus), chokecherry (Prunus virginiana), and bur oak. A few stands have grassy understories of timber oatgrass (Danthonia intermedia), Kentucky bluegrass (Poa pratensis), and/or little bluestem [286]. Interior ponderosa pine forests and woodlands are not abundant in North Dakota. Understory composition is similar to that of interior ponderosa pine in the Black Hills [123,136].

CO: On the Colorado Front Range, interior ponderosa pine generally occurs with Rocky Mountain Douglas-fir on north slopes and Rocky Mountain juniper on south slopes [213]. Quaking aspen commonly co-occurs on sites that have experienced past fires or other reoccurring disturbance [82]. Understory species include common juniper, wax currant (Ribes cereum), bearberry, spike fescue, blue grama, and buffalo grass (Buchloe dactyloides). At the forest-plains grassland ecotone, understory species may also include black grama (Bouteloua eriopoda), little bluestem, needlegrasses (Hesperostipa and Achnatherum spp.), western wheatgrass (Pascopyrum smithii), and cheatgrass (Bromus tectorum) [213]. Interior ponderosa pine is a minor species in western Colorado, where it occurs in Rocky Mountain Douglas-fir forests [163].

In southern Colorado, interior ponderosa pine lies between lower-elevation grassland or pinyon-juniper (Pinus-Juniperus spp.) and higher-elevation Rocky Mountain Douglas-fir. Grassy understories with blue grama, mountain muhly (Muhlenbergia montana), mutton grass (Poa fendleriana), Arizona fescue, and little bluestem are common on dry sites. On moister sites, shrubs such as Gambel oak (Quercus gambelii), wavyleaf oak (Q. × pauciloba), and bearberry may also be important [89].

UT: Interior ponderosa pine/shrub communities in central and southern Utah are usually the lowest coniferous forest type, and border shrublands or Colorado pinyon-Utah juniper (Pinus edulis-Juniperus osteosperma) woodland. Dominant understory species include curlleaf mountain-mahogany (Cercocarpus ledifolius), greenleaf manzanita (Arctostaphylos patula), black sagebrush (Artemisia nova), Gambel oak, and mountain snowberry (S. oreophilus). Interior ponderosa pine/mountain muhly occurs in central and southern Utah [319]. Interior ponderosa pine/grassland series also occur in northeastern Utah: dominant grasses are Idaho fescue, sheep fescue (F. ovina), and/or mutton grass. Rocky Mountain lodgepole pine, Utah juniper, and quaking aspen are seral in these habitat types [214].

Interior ponderosa pine in southeastern Nevada occurs mostly on northerly aspects of canyons. Associated species include Utah juniper, Gambel oak, rubber rabbitbrush (Chrysothamnus nauseosus), big sagebrush (Artemisia tridentata), bottlebrush squirreltail (Elymus elymoides), western wheatgrass, and cheatgrass [43].

Southwest: Interior ponderosa pine is the most common forest tree in the Southwest [320]. Vegetation patterns in southern New Mexico and Arizona are mostly determined by aspect and elevation. In southeastern Arizona, interior ponderosa pine forest lies on elevational and moisture gradients between dry, low-elevation Mexican pinyon-Chihuahua pine (Pinus cembroides-P. leiophylla var. chihuahuana)-Apache pine forest and/or Madrean oak woodland and moister, higher-elevation southwestern white pine (P. strobiformis)-Rocky Mountain Douglas-fir forest [28,33,133]. At 7,500 to 8,500 feet (2300 to 2600 m) elevation, interior ponderosa pine, Arizona pine, and encinal oaks tend to dominate dry, south- and west-facing slopes, while Rocky Mountain Douglas-fir and corkbark fir (Abies lasiocarpa var. arizonica) occupy north- and east-facing slopes. Madrean oak associates include Arizona white oak (Quercus arizonica), Gambel oak, Emory oak (Q. emoryi), and silverleaf oak (Q. hypoleucoides). Understories are dominated by grasses including pine dropseed (Blepharoneuron tricholepis), Arizona wheatgrass (Elymus arizonicus), prairie Junegrass, and screwleaf muhly (M. virescens) [28]. In high-elevation (8,400 to 9,300 feet (2500-2800 m)) mixed-conifer forest, Engelmann spruce, blue spruce (P. pungens), corkbark fir, Rocky Mountain Douglas-fir, southwestern white pine, and quaking aspen co-occur with interior ponderosa pine [125].

AZ: Associates in interior ponderosa pine/bunchgrass in northern Arizona include mountain muhly, mutton grass, Arizona fescue, bottlebrush squirreltail, blue grama, pine dropseed, deergrass (M. rigens), and prairie Junegrass [23]. Shrubs may be nearly absent to fairly common. If present, they are usually widely and irregularly spaced compared to more northern ponderosa pine communities. Fendler ceanothus (Ceanothus fendleri), wax currant, skunkbush sumac, greenleaf manzanita, Stansbury cliffrose (Purshia mexicana var. stansburiana), Apache plume (Fallugia paradoxa), and mountain-mahogany (Cercocarpus spp.) are among the most common shrubs in interior ponderosa pine/bunchgrass. The ponderosa pine type usually merges into Arizona chaparral at lower elevations of northern and central Arizona. It may also finger into riparian zones [58]. At higher elevations, the type merges into corkbark fir-spruce (Picea spp.) forest. Associates in the upper ponderosa pine zone include those shrubs also found in fir-spruce forest: common juniper, Oregon boxwood (Paxistima myrsinites), red raspberry (Rubus idaeus), mountain ninebark, and snowberry (Symphoricarpos spp.). Rocky Mountain Douglas-fir and quaking aspen may co-occur with interior ponderosa pine above 7,000 feet (2000 m) [66,75,226].

TX: Netleaf oak (Q. rugosa), silverleaf oak, and quaking aspen are common associates throughout western Texas. Colorado pinyon and alligator juniper (Juniperus deppeana) often form a woodland association with interior ponderosa pine on south slopes; Douglas-fir and southwestern white pine join interior ponderosa pine in a forest/bunchgrass association on moister slopes [2]. Understory associates include finestem tussockgrass (Nassella tenuissima), California brome (Bromus carinatus), Big Bend bluegrass (Poa strictiramea), bulb panicgrass (Panicum bulbosum), and pinyon ricegrass (Piptochaetium fimbriatum) [88]. In the Guadalupe and Chisos mountains, interior ponderosa pine dominates ponderosa pine-Douglas-fir-southwestern white pine parklands and is an associate in Chisos red oak (Q. gravesii)-Colorado pinyon woodlands. In the Davis Mountains, it occurs in ponderosa pine-southwestern white pine-Gambel oak associations [2,88,90,264].

Vegetation typings describing plant communities dominated by interior ponderosa pine are:

Related categories for SPECIES: Pinus ponderosa var. scopulorum | Interior Ponderosa Pine