Black Butte Research Natural Area Establishment Record

The Black Butte Research Natural Area (BBRNA) occupies the northeast side of a steep, southeast-trending ridge. This ridge forms a major topographic boundary between the western maritime climatic region and the temperate interior. Terrain is steep with an elevation gain of 1300 feet (396 m) in approximately 0.6 mile (1.0 km). Slopes of 80 percent or more are common within the RNA. Because of its location and steep elevation gradient, the BBRNA supports a complex mosaic of vegetation types. These include extensive stands of knobcone pine, various forms of chaparral including areas dominated by the narrow endemic Santa Lucia manzanita, and woodlands dominated by coast live oak (Quercus agrifolia). In addition, relictual stands of tanoak (Lithocarpus densiflora) occur in mesic, mixed evergreen woodlands dominated by canyon live oak (Quercus chrysolepis), which also contain significant proportions of madrone (Arbutus menziesii) and California bay (Umbellularia californica). Finally, scattered individuals of Coulter pine, (Pinus coulteri) occur primarily on steeply dipping rock outcrops at ecotones between chaparral and the mixed woodlands. Weakly developed riparian habitats are present in the bottoms of the two unnamed streams which drain eastward from Mt. Lowe. 

More than 200 taxa of vascular plants have been recorded from the BBRNA, including the three species with special status listed above: Santa Lucia manzanita, Hoover's bentgrass and club-haired mariposa lily.