Study Area
The study area consisted of about 276,000 ha in 7 watersheds in the southern portion of the upper Deschutes subbasin. Vegetation ranged from low-elevation shrublands, meadows, ponderosa pine and lodgepole pine forest to high-elevation parkland and spruce-fir and mountain hemlock forests. Ownerships were mixed and include about 142,000 ha of Federal general forest, 24,000 ha of Federal late successional forest reserves established by the Northwest Forest Plan (USDA and USDI 1994), 51,000 ha of wilderness and similar areas, and 59,000 ha of private lands.
Private lands constituted about 28 percent of the area (about 64,000 ha). These could be managed with a wide variety of treatments. For the purposes of this exercise, however, we assumed that private lands were a proxy for wildland-urban interface areas (WUI). WUI was an important stratification because fuel treatments were generally the highest priority management activity on private lands in this landscape. A consequence of our use of private lands as a surrogate for WUI was a potential overestimate of the rate of fuel treatments and an underestimate of other treatments on private lands.
Reserves were publicly owned lands (usually managed by the Forest Service or BLM) designated for special consideration and management (3 percent or about 7,000 ha). These were usually late successional reserves under the Northwest Forest Plan (USDA and USDI 1994) or other similar areas. Under some conditions, they may be managed with thinning or other fuel-reduction treatments. However, they were generally designated to maintain old forest structure and similar conditions. Wilderness was legally designated land managed for natural characteristics and included wilderness, state parks, and similar areas (15 percent or about 34,000 ha). Only natural disturbances (wildfire and insect/disease activity) were modeled in wilderness.
We recognized eight vegetation types based on maps provided by the Deschutes National Forest, and, for gaps in those data, information gathered during the Interior Columbia Basin Ecosystem Management Project (Hann and others 1997). These ranged from the lowest elevation juniper (Juniperus occidentalis) woodlands to alpine parklands:
Juniper woodland—shrub steppe areas generally capable of supporting grass, shrubs, and juniper but not closed forest.
Dry ponderosa pine (Pinus ponderosa)—areas capable of supporting ponderosa pine forests but generally not Douglas-fir (Pseudotsuga menziesii) or other tree species. These were transitional between forest and juniper woodland or shrub/steppe.
Mixed conifer dry—grand fir (Abies grandis) and Douglas fir forests at lower elevations and in relatively dry environments. Historically, these areas consisted mostly of large, open, ponderosa pine stands maintained by frequent ground fire (average 10 to 20-year fire return interval).
Mixed conifer moist—forests dominated by a variety of conifer species, including ponderosa pine, Douglas-fir, grand fir, sugar pine (Pinus lambertiana), incense cedar (Calocedrus decurrens), western larch (Larix occidentalis) and others. Under historical conditions, these somewhat wetter areas had less frequent natural fire than the dry mixed conifer type and were often dominated by large, widely spaced ponderosa pine.
Lodgepole pine (Pinus contorta) dry—lodgepole pine stands growing primarily on pumice soils. Soil and microsite conditions restricted other conifer species.
Upper montane cold—high-elevation forests dominated by Engelmann spruce (Picea engelmannii), mountain hemlock (Tsuga mertensiana), grand fir, subalpine fir (Abies lasiocarpa), lodgepole pine, and other species. This type occurred mostly within reserves or wilderness.
Upper montane moist—high-elevation forests that largely reflected westside climatic influences. Pacific silver fir (Abies amabilis), noble fir (Abies procera), Douglas-fir, and other species generally dominated.
Subalpine parkland—high-elevation mosaics of tree islands, alpine shrublands, and grasslands largely within reserves or wilderness.
Encyclopedia ID: p3392
