Boise National Forest

Boise National Forest
IUCN category VI (protected area with sustainable use of natural resources)
Boise National Forest
Location	Ada, Boise, Elmore, Gem, Valley, and Washington counties, Idaho, United States
Nearest city	Boise, ID
Area	2,267,000 acres (9,170 km2) (administered); 2,654,084 acres (10,740.70 km2) (proclaimed)
Established	July 1, 1908
Governing body	U.S. Forest Service
www.fs.usda.gov/boise

The Boise National Forest is a US national forest located north and east of the city of Boise, Idaho. It is about 2,654,000 acres (10,740 km²) in size, ranging in elevation from 2,600 to 9,800 feet (800 to 3000 m). The mountainous landscape developed through uplifting, faulting, and stream cutting. Most of the land lies within the Idaho Batholith, a large and highly erodible geologic formation. The major rivers that run through it include the Boise, the Payette and the South and Middle forks of the Salmon River. Portions of the Frank Church-River of No Return Wilderness, the Sawtooth Wilderness, and Sawtooth National Recreation Area are within the forest, although none of these areas are managed by Boise National Forest.

Conifer forest covers most of the Boise National Forest. Tree species include ponderosa pine, Douglas-fir, Engelmann Spruce, lodgepole pine, grand fir, subalpine fir, western larch, and whitebark pine. Shrubs and grasses grow in the non-forested areas. Wildflowers splash color in both forests and shrub-land.

The Forest contains large expanses of summer range for big game species like mule deer and elk. Trout are native to most streams and lakes. Oceangoing salmon and steelhead inhabit tributaries of the Salmon River.

In descending order of land area the forest is located in parts of Valley, Boise, Elmore, Gem, Ada, and Washington counties. Forest headquarters are located in Boise, Idaho. There are local ranger district offices in Cascade, Emmett, Idaho City, Lowman, and Mountain Home.

Map of Boise National Forest (orange)

Forest history

Boise National Forest was created on July 1, 1908 from part of Sawtooth National Forest and originally covered 1,147,360 acres (464,320 ha). The President was given the authority to establish forest reserves in the U.S. Department of the Interior by the Forest Reserve Act of 1891. With the passage of the Transfer Act of 1905, forest reserves became part of the U.S. Department of Agriculture in the newly created U.S. Forest Service. Present-day Boise National Forest was protected as part of Sawtooth Forest Reserve upon the reserve’s creation on May 29, 1905 and expansion on November 6, 1906. After forest reserves were renamed national forests in 1908, Boise National Forest was split from Sawtooth into an independent national forest. On April 1, 1944 the entirety of what was then Payette National Forest was transferred to Boise National Forest, and simultaneously Weiser and Idaho national forests were combined to reestablish the present-day Payette National Forest, which is to the north of Boise National Forest. The original Payette National Forest had been established on June 3, 1905 as Payette Forest Reserve.

Management

Boise National Forest is managed by the U.S. Forest Service, an agency within the Department of Agriculture as five units called ranger districts. The ranger districts are Cascade (400,000 acres or 1,600 square kilometers), Emmett (350,000 acres or 1,400 square kilometers), Idaho City (400,000 acres), Lowman (400,000 acres), and Mountain Home (650,000 acres or 2,600 square kilometers), and each has an office in their respective cities and a district ranger who manages the ranger district. Forest headquarters are located in the city of Boise, and the forest supervisor, or the top forest official, is Cecilia Seesholtz. There have been 2,654,084 acres (10,740.70 km²) of Idaho proclaimed to be part of Boise National Forest, however the forest manages only about 2,267,000 acres (917,000 ha). The proclaimed boundary is set and can only be changed by Congress, but the administered boundary is can be shifted among neighboring national forests without congressional approval. For management (and from the visitor’s perspective) the forest’s boundaries are its administered area.

Sawtooth National Forest manages 150,071 acres (607.32 km²) of Boise National Forest as part of the Sawtooth Wilderness in Sawtooth National Recreation Area. There are 332,971 acres (1,347.49 km²) of the proclaimed area of Boise National Forest in the Frank Church-River of No Return Wilderness, which is largely managed by Salmon-Challis National Forest. The Indian, Pistol, and Elkhorn Creek drainages of the Frank Church Wilderness are designated as part of Boise National Forest but are managed by Salmon-Challis National Forest. One section of Boise National Forest in the Frank Church Wilderness is administered jointly by Boise and Salmon-Challis national forests. The Stibnite region of the upper East Fork South Fork Salmon River drainage within Boise National Forest’s proclaimed area is managed by Payette National Forest. Boise National Forest manages a small section of Payette National Forest’s designated area east of Council and a larger area of Sawtooth National Forest between Mountain Home and Fairfield.

Natural resources

See also: Ecology of the Rocky Mountains

Flora

An estimated 76 percent of Boise National Forest is forest, which is considered to be land that is capable of supporting trees on at least 50 percent of its area. The forests are primarily coniferous evergreen forests dominated by ponderosa pine, lodgepole pine, and Douglas-fir at lower elevations and Engelmann spruce, subalpine fir, and whitebark pine at higher elevations. Grand fir and western larch can be found in the northern part of the forest where there are moister conditions. Quaking aspen, a deciduous tree, can be found in stands among conifers throughout the forest at elevations from 5,000 feet (1,500 m) to 11,000 feet (3,400 m). Non-forested areas occupy 23 percent of the forest, primarily on south-facing slopes, lower elevations in the forest’s southern latitudes, or high-elevation areas. These non-forested areas are those dominated by grasses, forbs, or shrubs.

The warmest, driest forested areas occur at elevations from 3,000 feet (910 m) to 6,500 feet (2,000 m) and on south-facing slopes that are steep and dry. These forests are dominated by ponderosa pine, which persists due to the presence of frequent non-lethal fires. Douglas-fir occasionally occur in these forests alongside ponderosa pine, particularly at higher elevations. The understory is comprised of bluebunch wheatgrass, Idaho fescue, mountain snowberry, and bitterbrush in drier areas and elk sedge, pinegrass, white spirea, mallow ninebark, and common snowberry at higher elevations.

In cool, moist areas ranging from 4,800 feet (1,500 m) to 6,800 feet (2,100 m), Douglas-fir dominates. Lodgepole pine and quaking aspen may be found alongside Douglas-fir in cooler areas, particularly where frost pockets form. Understories in this forest type are dominated by mountain maple, mountain ash, and blue huckleberry in moister areas and white spirea, common snowberry, elk sedge, and pinegrass in drier areas. Between elevations of 3,400 feet (1,000 m) and 6,500 feet (2,000 m) in the moist northern parts of the forest, grand fir dominates and western larch is found in early successional areas. Understories are also made of mountain maple, mountain ash, blue huckleberry, and mallow ninebark. Subalpine fir dominates at elevations from 4,800 feet (1,500 m) to 7,500 feet (2,300 m) along with mountain maple, serviceberry, Scouler’s willow, Sitka alder, menziesia, Utah honeysuckle, and mountain ash.

Lodgepole pine can dominate in cold, dry areas at elevations from 5,200 feet (1,600 m) to 9,200 feet (2,800 m). Understory vegetation can be sparse but include grasses, forbs, and huckleberries and grouse whortleberry. Fires in lodgepole pine-dominated forests are typically lethal to trees and understories alike. At the highest elevations, forests consist of subalpine fir alongside whitebark pine and Engelmann spruce. Grasses and forbs tolerant to freezing throughout the growing season occupy the understory.

In non-forested areas at lower elevations with little precipitation, sagebrush typically dominates. Species that commonly occur with sagebrush include Sandberg bluegrass, wild onion, milk vetches, bluebunch wheatgrass, bitterbrush, gray horsebrush, green rabbitbrush]], and others. In riparian areas below 5,500 feet (1,700 m), trees such as black cottonwood, narrowleaf cottonwood, thinleaf alder, water birch, mountain maple can be found with shrubs such as chokeberry and willows. Treeless riparian areas are dominated by willows along with thinleaf alder, chokecherry, mountain maple, shrubby cinquefoil fireweed, saxifrage, and grasses.

Sacajawea’s bitterroot (Lewisia sacajaweana) is a plant species endemic to central Idaho, including parts of Boise National Forest, being found nowhere else in the world. Only about two dozen populations of the plant are known to exist, and three-quarters of the populations are in Boise National Forest. It is usually found at elevations ranging from 5,000 feet (1,500 m) to 9,500 feet (2,900 m) above sea level and produces white flowers shortly after snowmelt. The forest contains habitat capable of supporting Ute lady’s tresses, a plant listed as threatened under the Endangered Species Act.

Climate

Temperatures in Boise National Forest are generally warm to hot during the summer with high temperatures often ranging from 80 °F (27 °C) to 90 °F (32 °C) throughout the forest. Lower elevations can experience temperatures in excess over 100 °F (38 °C) during the summer. In the winter average temperatures are between 29 °F (−2 °C) and 9 °F (−13 °C). Idaho’s mountain ranges can block cold Arctic air from moving into the area in the winter, but when it does, these cold air masses can stagnate in the Snake and Salmon river valleys, enabling very cold temperatures to persist. Summer and fall are generally dry, while intense short-duration thunderstorms often occur in late spring and early summer as moisture from the Gulf of Mexico interacts with warm temperatures and steep topography. Average snowfall ranges from 55 inches (140 cm) to 70 inches (180 cm), where greater amounts occur at higher elevations. Warm, moist air from the Pacific Ocean often brings rain at lower elevations in addition to snowfall throughout the forest during the winter. The influence of these Pacific maritime air masses increases as latitude increases in the forest. The growing season within the forest ranges from over 150 days in lower elevations to less than 30 days in alpine areas.

External Links

• Boise National Forest – Official site