Understory

The Millard Canyon Research Natural Area occupies the eastern side of the Middle Branch of Millard Canyon, a tributary of the San Gorgonio River. Although located within the drainage of the Salton Sink in the southeastern portion of the San Bernardino Mountains, the vegetation is distinctly cismontane with only a small interior-desert influence. Slope aspect is varied with north, south, and west exposures predominating.

Grass Lake Research Natural Area contains the largest sphagnum bog in California. The RNA is a diverse mosaic of wetland communities in a montane valley, on the rim of the Lake Tahoe Basin. Six different terrestrial communities are represented: sphagnum bog, montane meadow, Jeffrey pine forest, red fir forest, lodgepole pine forest, and aspen riparian forest.More than 270 species of vascular plants have been identified from the RNA vicinity. Tree species occurring in the RNA include red fir (Abies magnifica), western white pine (Pinus monticola), lodgepole pine (Pinus contorta var. murrayana) ...

The Agua Tibia Research Natural Area contains three major vegetation types: bigcone Douglas-fir (BCDF) forest, montane manzanita chaparral, and canyon live oak forest. The area contains two Forest sensitive plants, both of which are listed by the California Native Plant Society. Aside from BCDF, it contains six plant species at or near the southern extent of their range.

Station Creek Research Natural Area is comprised of the north facing slope of the South Fork American River canyon, on the western slope of the Sierra Nevada, approximately 10 mi (16 km) west of Echo Summit. The RNA supports mature stands of Sierran mixed conifer forest, while surrounding lands are subject to timber harvest. This mature forest provides important habitat for the forest-sensitive California spotted owl (Strix occidentalis californicus), and goshawk (Accipiter gentilis), and potentially for other forest-sensitive vertebrates.

The Mount Pleasant Research Natural Area is underlain entirely by granitic rock. The topography is gradual over much of the area ascending only ca. 1360 ft. (415 m) in ca. 2.25 miles (3.6 km). The southwest-facing slopes of the Mt. Pleasant-Spanish Peak crest are drained by several branches of Mill Creek. The main branch and the Right Hand Salt Rock branch are the two principal streams in the RNA. Both are permanent and of relatively low volume, emanating from springy meadows, riparian thickets, and bogs on the upper southwest slopes.

Caspar Creek experimental watersheds are located on the Jackson Demonstration State Forest. Sponsors are the Pacific Southwest Research Station (PSW), USDA Forest Service, and the California Department of Forestry and Fire Protection (CDF). Both organizations have been working cooperatively since 1962.The 483-ha North Fork of Caspar Creek and the 424-ha South Fork of Caspar Creek have been gaged continuously since 1962. The watersheds are Iocated about 7 km from the Pacific Ocean and about 10 km south of Fort Bragg in northwestern California at 39o21'N 123o43'W. Watersheds generally have a sou...

The Organ Valley Research Natural Area (OVRNA) is distinguished by the presence of stands of open and dense Engelmann oak woodland along with areas of southern mixed chaparral, chamise chaparral, and southern coast live oak riparian forest. All community types within the OVRNA are restricted to Southern California, two of which only occur on the Cleveland National Forest. Six Forest sensitive plant species are known to occur within the RNA boundaries.The OVRNA encompasses the south slope of Black Mountain, and drainage of the area is to the southwest. The entire OVRNA is underlain by granitic ...

The Whippoorwill Flat Research Natural Area contains a high concentration of Great Basin montane vegetation types represented by both typical and atypical forms. The variety in such vegetation types as pinyon-juniper, bristlecone and limber pine forests, and sagebrush scrub is a result of the combination of both substrate and climatic diversity. Although the pinyon-juniper element has the largest aerial representation and offers high potential for scientific study, all other vegetation types in the area are large and varied enough to be suitable for study, as well.

The Hall Canyon Research Natural Area is located on the western slopes of the San Jacinto Mountains, the largest and northernmost of the California Peninsular Ranges. Hall Canyon is a southwesterly trending narrow drainage dropping off the slopes of Black Mountain, the end point of a prominent northwestern ridge of San Jacinto Peak. Two roughly parallel southwest trending ridges form the boundaries of Hall Canyon and confine the headwaters of Indian Creek, a tributary to the San Jacinto River.

The Moses Mountain Research Natural Area is underlain by both granitic and schistose metamorphic rocks. The latter generally occupy the lower slopes while the former and predominant on the ridges and upper slopes. The RNA occupies a portion of the southward-flowing North Fork of the Middle Fork of the Tule River. A large portion of the east face of Moses Mountain is included.