The Siskiyou Mountains are a coastal mountain range in the northern Klamath Mountains in northwestern California and southwestern Oregon in the United States. They extend in an arc for approximately 100 miles (160 km) from east of Crescent City, California northeast along the north side of the Klamath River into Josephine and Jackson counties in Oregon. The mountain range forms a barrier between the watersheds of the Klamath River to the south and the Rogue River to the north.
These mountains are not the highest or most dramatic in the Klamath Mountains but are subtly beautiful, botanically diverse, and the wildest the region has to offer. Due to the relief so close to the Pacific Ocean, the peaks receive more precipitation than the surrounding land. This leads to forests that grow with heavy vegetation. Diversity abounds because western canyons can receive over 100 inches (2,500 mm) of rain in some winters while eastern areas are slightly more arid. Because the Siskiyous trend both north and south and then east and west, it holds species that range from coastal, like coast redwood, to Cascadian, like Alaska yellow-cedar and Pacific silver fir.
Interstate 5 passes through the Siskiyou Mountains at Siskiyou Summit, located just north of the Oregon/California border, and just south of Ashland, Oregon. Siskiyou Summit is the highest pass on Interstate 5, at 4,310 feet (1,310 m). This pass is one of the most treacherous in the Interstate highway system. The California side has a more gradual ascent/descent, but on the Oregon side of the pass (the side which is more hazardous), the freeway gains (loses) 2,300 feet (700 m) in elevation over a 7-mile (11 km) stretch of freeway. In addition, the pass includes several hazardous curves, and is frequently hit with bad weather (including snow, ice, and fog) during winter storms. During winter, it is common for the highway to be closed one to four times by transportation authorities due to hazardous conditions. The speed limit is 55 miles per hour (89 km/h), but lower limits are set for larger vehicles.
Ecology and Protection
There is considerable biodiversity within the Siskiyou Range, including extensive forests. Forests vary by elevation and relative locations, being primarily divided into Mixed Evergreen Forests, Montane Forests, and Subalpine Forests.
The occurrences of tree species are divided by these forest types. Exceptions to this exist. Coast Douglas-fir (Pseudotsuga menziesii subsp. menziesii) occurs in both Mixed Evergreen and Montane Forests. Lawson's Cypress (also known as Port Orford Cedar, Chamaecypraris lawsoniana) occurs throughout the range west of the summit. White Fir (Abies concolor subsp. lowina) occurs in Montane and Subalpine Forests above 4,000 feet (1,200 m). In the Montane Forest, occurring in the snowzone, Sugar Pine (Pinus lambertiana) also occurs.
The diversity of fauna in the region is exhibited by the number of amphibian, reptile, and avian species in the region. Many of the amphibian and reptiles are endemic species. The eponymous endangered Siskiyou Mountains salamander is found within this mountain range; in addition there is also the Scott Bar Salamander. The variety of habitats in the mountains contributes to the number of bird species in the area, because the birds have more variety of habitat available to them. However, many birds disperse from the area following the breeding season. These birds include the endangered Spotted Owl, which lives in the elevations up to 5,800 feet (1,800 m).Endangered salmon live in the Rouge and Klamath watersheds.
Total Range: 100 miles (160 km)