Forest and woodland habitats can be categorized into the following types:
Oregon white oak characterizes most oak woodlands and savannas, which can still be found throughout western Oregon. They have been declining, but are important to wildlife, and are a priority habitat in most western Oregon ecoregions. From Eugene south, California black oak increases in importance, and in southwestern Oregon a number of other oaks, canyon live oak, tanoak, and chinquapin can be important. Oak woodlands and savannas are included in the following ecological systems: North Pacific Oak Woodland, Willamette Valley Upland Prairie and Savanna, and Mediterranean California Mixed Oak Woodland. Two mixed ecological systems, the Mediterranean California Lower Montane Black Oak-Conifer Forest and Woodland and East Cascades Oak-Ponderosa Pine Forest and Woodland are also included here.
Westside Dry Douglas Fir-Madrone Forest and Wooodland
These are the common dry Douglas fir forests and woodlands found throughout western Oregon, usually with Douglas-fir as the only conifer, sometimes with madrone codominant. They are part of the North Pacific Dry Douglas-fir Madrone Forest and Woodland Ecological System.
Aspen or Rocky Mountain Maple Forests and Woodlands
Quaking aspen can dominate small forest and woodland stands found in the mountains and foothills in eastern Oregon. While not very abundant, they can be very important to many species of wildlife, and are declining in many areas. Mixed aspen and conifer forests also are included here, so in Oregon this habitat includes two ecological systems: Inter-Mountain Basins Aspen-Mixed Conifer Forest and Woodland and Rocky Mountain Aspen Forest and Woodland.
Mixed Hardwood-Conifer Forest or Woodland
Bigleaf maple, red alder and mixed low-elevation conifers characterize this habitat which is widespread in western Oregon, and extends into western Washington and northern California. Common conifers include Douglas-fir, western hemlock, and western red cedar, although all westside conifers can occur. It is the North Pacific Lowland Hardwood mixed Conifer Forest ecological system.
Coastal Spruce, Port Orford Cedar or Redwood Forest
Some giant conifer forests dominate the coastal strip, often in areas with frequent coastal fog. They are Sitka spruce dominated forests extending from central Oregon north to Alaska, Port Orford cedar forests found from Coos Bay south to Brookings, and Coast Redwood forests found near the California border. They are wet, foggy conifer forests, often with dense evergreen shrub understories, part of either the North Pacific Hypermaritime Sitka Spruce Forest or California Coastal Redwood Forest, or occasionally the California Coastal Closed-Cone Conifer Forest and Woodland ecological system.
Western Oregon Douglas-fir Hemlock Forest
These are the common, giant conifer forests in the Coast Range and lower Cascades foothills, dominated by Douglas-fir, western hemlock and western red cedar. It includes two ecological systems, North Pacific Maritime Dry-Mesic Douglas-fir-Western Hemlock Forest and North Pacific Maritime Mesic Douglas-fir-Western Hemlock Forest.
Subalpine Forests and Woodlands/Spruce-fir
The highest elevation forests in the Cascades, Blue Mountains and Wallowa Mountains are dominated by a mix of high elevation conifers, mainly subalpine fir, Engelmann spruce, mountain hemlock and whitebark pine. They include 2 forest ecological systems and two subalpine parkland systems: Rocky Mountain Subalpine Dry-Mesic Spruce-Fir Forest and Woodland, Rocky Mountain Subalpine Mesic Spruce-Fir Forest and Woodland, North Pacific Maritime Mesic Subalpine Parkland, and Northern Rocky Mountain Subalpine Woodland and Parkland.
Eastside Montane Mixed Conifer Forests and Woodland
These forests occur above the Ponderosa pine zone and below the subalpine forests east of the Cascades. They are characterized by mixed conifers such as Douglas fir, grand fir, and western larch, occasionally with western red cedar and often with some Ponderosa pine present. Northern Rocky Mountain Dry-Mesic Montane Mixed Conifer Forest, Northern Rocky Mountain Mesic Montane Mixed Conifer Forest, East Cascades Mesic Montane Mixed-Conifer Forest and Woodland, or the Northern Rocky Mountain Western Larch Woodland and Savanna.
Siskiyou Mixed Conifer
The most diverse forest habitats in Oregon are the Siskiyou Mixed Conifer forests and woodlands. They include a mix of 14 different conifer species, habitats found on various soils, including serpentine (heavy mineral), granitic, and sedimentary, and a range of conditions from giant moist conifers with a tall, evergreen hardwood understory to open pine savanna. This habitat includes six main ecological systems: Mediterranean California Dry-Mesic Mixed Conifer Forest and Woodland, Mediterranean California Mesic Mixed Conifer Forest and Woodland, Mediterranean California Red Fir Forest, Klamath-Siskiyou Lower Montane Serpentine Mixed Conifer Woodland, Klamath-Siskiyou Upper Montane Serpentine Mixed Conifer Woodland, and Mediterranean California Mixed Evergreen Forest.
Lodgepole Pine Forest and Woodland
Lodgepole pine is most common in the East Cascades, where it occurs on deep pumice from the explosion of Mount Mazama that created Crater Lake. But is also occurs throughout the Blue Mountains, in the high Cascades, and occasionally in the Siskiyou Mountains. These are dense, usually fire dependant Montane forests. They mostly are in two systems, the Rocky Mountain Poor Site Lodgepole Pine Forest on ash and lava, and Rocky Mountain Lodgepole Pine Forest on more typical sites in the Blue Mountains, and the uncommon Sierra Nevada Subalpine Lodgepole Pine Forest and Woodland found in the Klamath Mountains and southern Cascades.
Ponderosa Pine Forest and Woodland
Ponderosa pine forests dominate the lower elevations in the mountains and foothills of the East Cascades and Blue Mountains. They also occur in southwestern Oregon and less frequently in the Willamette Valley and West Cascades. They have declined as fire has been suppressed, since fires maintain the open woodland conditions they usually require. Most of the Ponderosa pine habitats are in the Northern Rocky Mountain Ponderosa Pine Woodland and Savanna ecological system, but some are mapped as the East Cascades Oak-Ponderosa Pine Forest and Woodland or the California Montane Jeffrey Pine Woodland system.
Juniper Woodland or Savanna
Western juniper woodlands and savannas are widespread in the Blue Mountains, the southern part of the East Cascades, and in the Northern Basin and Range. Oregon represents the center of the distribution for western juniper, which historically formed ancient open woodlands covering much of central Oregon and the Steens Mountains. These old-growth juniper woodlands continue to decline. However, for some reason, western juniper is now invading many of the sagebrush steppe areas in southeastern and central Oregon, creating problems for many sagebrush species. In Oregon, this habitat is entirely included in the Western Columbia Plateau Western Juniper Woodland and Savanna ecological system.
Mountain Mahogany Shrublands or Woodlands
Curl-leaf mountain mahogany is an important wildlife species, which occurs on rocky rims, cliffs, and Montane areas protected from fire throughout eastern Oregon, and occasionally in southwestern Oregon. It is a very small tree or tall shrub, and is expanding a bit with fire suppression, but does not compete with the much taller conifers. It occurs in the Inter-Mountain Basins Mountain Mahogany Woodland and Shrubland ecological system. Birchleaf mountain mahogany is considered to be part of the chaparral habitat type.
Westside Montane Mixed Conifer Forest
The common, Montane conifer forests west of the Cascade crest, dominated by Pacific silver fir, mountain hemlock, noble fir, and Shasta red fir are included in this habitat. They are tall conifer forests, found between 2,500 and 5,500 feet in the mountains, with a wide range of understory conditions. There are 4 ecological systems within this habitat group: North Pacific Mountain Hemlock Forest, North Pacific Mesic Western Hemlock-Silver Fir Forest, North Pacific Dry-Mesic Silver Fir-Western Hemlock-Douglas-fir Forest, and the Mediterranean California Red Fir Forest ecological system (which includes noble fir forests).