Oregon Mountain Botanical Area

The Oregon Mountain Botanical Area is a rare plant site located on the Wild Rivers Ranger District of the Rogue River-Siskiyou National Forest in Southwest Oregon’s Josephine County. At 2,623 acres, it is one of the larger Botanical Areas designated by the 1989 Siskiyou National Forest Management Plan (SNF Plan). Even so the SNF Plan adopted the smaller scaled-down version of two options with the larger encompassing 4,401 acres.

It stretches from the Oregon/California border north to a little south of O’Brien, Oregon and is part of an area in Southwest Oregon and Northwest California (Josephine, Curry and DelNorte counties) that John Sawyer, late Professor Emeritus of Biology at Humboldt State University and famed botanist, identified as having one of the highest percentages of rare plants in North America.

The Oregon Mountain Botanical Area is accessed by Forest Service road 4402. Also known locally as the historic Wimer Road, FS road 4402 runs through much of the Botanical Area, along the West Fork Illinois River.

Most of the area here is underlain by the ultramafic/serpentine soils of an ancient geologic formation known as the Josephine Ophiolite or Josephine Ultramafic Sheet. The Josephine Ophiolite is one of 5 ophiolite sequences in the Klamath-Siskiyou Serpentines.

Botanists know the National Forest and Bureau of Land Management Public Lands (BLM) on the west side of the Illinois Valley as the focal point for rare plants associated with serpentine soils—some of which are found nowhere else in the world. This area roughly spans federal public lands from Eight Dollar Mountain in the north to the Oregon/California border in the south. It includes the following: the Oregon Mountain, Rough and Ready Creek and Eight Dollar Mountain Botanical Areas on National Forest lands and the West Fork Illinois, Waldo-Takilma, French Flat, Rough and Ready Creek, Woodcock Bog and Eight Dollar Mountain Areas of Critical Environmental Concern (ACEC) on BLM lands.

The Oregon Mountain Botanical Area and the West Fork Illinois ACEA adjoin each other in one section.

Senator Wyden’s O&C Land Grant Act of 2013 (S. 1784) would include the adjacent BLM lands in the Illinois Valley Salmon and Botanical Area.

CAUTION: Whisky Creek, the West Fork Illinois River and FS road 4402 are infested with the Port Orford Cedar Root Disease (Phytophthora lateralis). Port Orford cedar along Whisky Creek and the West Fork Illinois River are dying from this non-native root disease. The virulent plant pathogen is spread in water and mud on vehicles. Do not transfer mud or water from the area into uninfected areas. Mud or soil on vehicles can easily spread Port Orford cedar root disease to uninfected stream systems.

The introduction of the P. lateralis is irreversible. It’s fatal to Port Orford cedar. The cedar is a component of rare plant communities along stream banks and in Serpentine Darlingtonia Wetlands.

The Port Orford cedar root disease was introduced by off-highway vehicles using a Forest Service gravel pit as a play area. The gravel pit is located off road 4402 in the headwaters of Whisky Creek in the South Kalmiopsis Roadless Area. While the root disease introduction occurred in the 1990s, the Forest Service has yet to address the source of the infection.

Learn more about the ecological importance of Port Orford cedar and why the lose of large old irreplaceable cedars—especially along streams—is so environmentally damaging here.