The 146 ha Bull Run RNA is located on mountain slopes in a cirque adjacent to the crest of the Cascades in Clackamas County, Oregon. Because this tract lies within the Bull Run Watershed, the municipal water supply for Portland, access is strictly controlled. The topography is generally steep with slopes of 30 to over 60 percent in most areas, with a limited area occupied by gentle slopes and benches. Springs can be found in middle and lower portions of the tract, and streams have cut steep-walled canyons in several locations. Elevations range from 1,000 to 1,370 m. The RNA is in the Western Hemlock and Pacific Silver Fir zones, as designated by the Oregon Natural Heritage Plan, with a dense herbaceous understory. Forest stands are a mixture of noble fir (Abies procera), Pacific silver fir (Abies amabilis), western hemlock (Tsuga heterophylla) and Douglas fir (Pseudotsuga menziesii), with Douglas fir being only a minor component of stands over 1,100 m. All forests are old growth with ages of over 250 years. Many of the largest trees, mainly Douglas fir, western hemlock, and Pacific fir, are 90 to 130 cm d.b.h. and over 45 m. tall. Due to the limited access, the area is essentially free of human impact.

Township/Range/Section:

Portions of sec 27 and 34, T1S, R8E.

Latitude:

45,26N

Longitude:

121,49W

Quad Map:

7.5' Bull Run Lake - scale 1:24,000

Threatened or Endangered Species:

Canis lupus (wolf) may be found here. Sensitive plants are: Cimicifuga laciniata, Isopyrum hallii and Polystichum andersonii.

Exotic Species Present:

Plant Communities:

Mixed true fir, noble fir, western or mountain hemlock, and Douglas fir forests. Communities are: Pacific silver fir/rosy twisted-stalk and Pacific silver fir/Alaska huckleberry.

Aquatic Features Present:

Springs are common in middle and lower portion of the RNA, and streams have cut sharp, steep-walled canyons.

Soils:

Soils have been mapped. Podzols developed in glacial till classified into 2 soil series - Jackpot and Last Chance. Soil profile described in guidebook. Soil type map in guidebook.

Other Physical Features:

Limited areas of rock slides. Some sharp, steep-walled canyons.

Past Disturbance History:

Other Comments:

Entry permit and key required for access by foot or boat