1.Adorni 1.Adorni (Cheng 1997a, Sawyer 1981a) Location This established RNA is on the Six Rivers National Forest. It lies about 3 miles (5 km) N. of Weitchpec, Humboldt County, covering portions of sects. 25 and 26 T10N, R4E HBM (41°14'N., 123°41'W.), USGS Weitchpec quad (fig. 3). Ecological subsections – Gasquet Mountain Ultramafics (M261Ab) and Eastern Franciscan (M261Ba). Target Element Port Orford-Cedar (Chamaecyparis lawsoniana) Distinctive Features Port Orford-Cedar (POC): This species is restricted to the Klamath Mountains and the adjacent S. Oregon Coast Figure 3—Adorni RNA Ranges. Throughout much of its range it is threatened by root rot disease (Phytophthora lateralis), and suitable areas for protection are needed. The area is representative of the low-elevation, mesic portion of the W. Klamath Mountains. In comparison with Upper Goose Creek (#91), however, it is less mesic, and such species as Rhododendron macrophyllum, western hemlock (Tsuga heterophylla), and giant chinquapin (Chrysolepis chrysophylla) are rare or absent. POC is more widespread in the forest away from drainage bottoms than at Upper Goose Creek. In comparison to Cedar Basin (#15), L.E. Horton (#50), and Rock Creek Butte (#70) candidate RNAs, Adorni is a warmer, less montane environment largely without ultramafic substrate. POC in Adorni is less restricted to stream courses than those in Cedar Basin, L.E. Horton, and Rock Creek Butte. Rare Plants: Erythronium citrinum and Lilium rubescens are members of CNPS List 4 species. Large Tanoak (Lithocarpus densiflorus): A small area in the SW. part of the site has several exceptionally large specimens of tanoak. The largest individuals reach 4 ft (1.2 m) dbh and heights of 170 ft (52 m). Physical Characteristics The area covers 700 acres (283 ha) and is drained by Aikens Creek, a tributary of the Klamath River. Topography is steep (30-70 percent slopes) with few terraces and typically abrupt ridges, particularly in the lower E. portion. Active slumping occurs along both of the major streams. Elevations range from 620 to 2580 ft (189-786 m). The area is underlain by phyllites, schists, and outcroppings of sheared black slate, all part of the Upper Galice formation. There are also small outcroppings of Josephine Peridotite (serpentinite). Soils are primarily of the Sheetiron series with about 20 percent Hugo series. Precipitation is estimated at 70 inches/year (1778 mm/year), concentrated between November and March. Snow falls commonly during this period but does not accumulate. High temperatures in the 80s and 90s °F (about 27-32 °C) are expected in the summer, whereas winter average lows are in the low 30s °F (about 0 °C). Association Types Thirty releves are compiled to form association tables that suggest two types of forest occur in the area. Sizes of associations are not indicated. 12 USDA Forest Service General Technical Report PSW-GTR-188. 2004. 1.Adorni The target element, Port Orford-cedar, is found in all areas of the RNA. It was not designated as a distinct vegetation type because of the overall dominance of Douglas-fir and tanoak. Keeler-Wolf (1990c) mapped the distribution of Port Orford-cedar; it is 209 acres (85 ha). Douglas-Fir/Goodyera oblongifolia (81100): This association is typical of the two-storied Douglas-fir-hardwood forest of the Klamath Mountains ecological section (fig. 4). A canopy of Douglas-fir (138 trees/ha) and Port Orford-cedar (109 trees/ha) overlies a subcanopy of tanoak (198 trees/ha), Pacific madrone (Arbutus menziesii, 40 trees/ha), and California bay (Umbellularia californica, 10 2 trees/ha). Total basal area for this forest averages 149 m /ha with Douglas-fir comprising 52 percent; Port Orford-cedar, 25 percent; and Pacific madrone, 15 percent of the cover. All trees are reproducing in these uneven-aged stands. The dense understory is dominated by Vaccinium ovatum and patches of Gaultheria shallon. Herbs include Goodyera oblongifolia, Trillium ovatum, Oxalis oregana, Clintonia uniflora, and Hierochloe occidentalis. In all, 22 species of shrubs and 22 species of herbs are noted in the releves. The Douglas-fir/Goodyera oblongifolia forest has deeper and less rocky soils with steeper and more unstable slopes than the tanoak/Rhamnus type. One active slump (Holland 61510) is being colonized by white alder (Alnus rhombifolia), tanoak, Douglas-fir, and Port Orford-cedar. Much of the Douglas- fir/Goodyera forest in the sample was selectively logged in 1965. This disturbed area shows a heterogeneous mix of species, depending on the degree of disturbance. Ceanothus velutinus and white alder are common with dense Vaccinium ovatum and reproductions of Douglas-fir, Pacific madrone, and tanoak. Tanoak/Rhamnus californica (81400): This is a more open forest, differing primarily in structure from the previous type. Trees have higher average 2 density (674/ha), but lower average basal area (65 m /ha), than the Douglas- Figure 4—Adorni, general fir/Goodyera oblongifolia type. Tanoak has the highest relative densities (35 structure of Douglas- percent) followed in order by Pacific madrone (22 percent), Douglas-fir (18 fir/Goodyera oblongifolia forest percent), sugar pine (Pinus lambertiana) (12 percent), Port Orford-cedar (5 type in Adorni RNA. (1988) percent), and incense-cedar (Libocedrus decurrens) (5 percent). Douglas-fir has the highest relative cover (37 percent) followed by sugar pine (24 percent), tanoak (12 percent), madrone (12 percent), Port Orford-cedar (10 percent), incense-cedar (4 percent), and canyon live oak (Quercus chrysolepis) (2 percent). This forest is less productive than the previous type because it contains slower growing Port Orford-cedar. The understory is more xeric than the other forest, with Rhamnus californica, Arctostaphylos manzanita, Toxicodendron diversilobum, and Xerophyllum tenax common (11 shrub and 18 herb species encountered on releves). Both forest types appear to be climax with compositional and structural differences related to soil depth, slope steepness, and aspect. Plant Diversity One hundred thirty-three taxa of vascular plants are listed. Conflicting Impacts Road building associated with clear-cutting upstream from the area threatens the Port Orford-cedar through potential root rot invasion, but the disease was not present in the area as of 1988. A portion of the western third of the area was logged in the 1960s; however, the operation was selective enough so that large continuous areas were not affected. USDA Forest Service General Technical Report PSW-GTR-188. 2004. 13 2.Agua Tibia 2.Agua Tibia (Eagle Crag) (Frazier 1989, Martin 1990a) Location This established RNA is on the Cleveland National Forest, Palomar district, in the Agua Tibia Mountains in N. San Diego County. It lies approximately 50 miles (80 km) N. of San Diego and 75 miles (120 km) S. of Los Angeles. The RNA falls entirely within the Agua Tibia Wilderness. The study area is included in portions of sects. 13, 14, and 15 T9S, R1W (33°22'30"N., 116°56'W.), USGS Vail Lake quad (fig. 5). Ecological subsection – Palomar-Cuyamaca Peak (M262Bo). Target Elements Bigcone Douglas-Fir (Pseudotsuga macrocarpa) and Canyon Live Oak (Quercus chrysolepis) Figure 5—Agua Tibia RNA Distinctive Features Dashed line = Ecological study area Solid gray line = RNA Boundary Fossil evidence for bigcone Douglas-fir dates to the Pliocene, 7 million years ago. It is endemic to S. California and limited in its range, currently from the Mount Pinos region of Kern County to Chariot Canyon, S. of Banner, San Diego County. The population within the RNA is of interest for its great age, size, purity of stand, remoteness, and proximity to its S. limit. Dense stands are found on steep slopes in association with canyon live oak, comprising a fairly distinct and pure stand of a bigcone Douglas-fir-canyon live oak forest. Pacific madrone (Arbutus menziesii) is common in the Pacific Northwest but quite rare in S. California. The grove within the RNA represents the extreme S. limit for this species; only one other grove, on Rodriguez Mountain (less than 10 miles [16 km] to the S. of this grove), is known to be farther S. As with the bigcone Douglas-fir, Pacific madrone seems to be limited to mesic sites. Rare Plants: Monardella macrantha ssp. halli (Hall’s Monardella) and Linanthus orcutti (both CNPS list 1B) are found within the RNA. Southern Extents: Arbutus menziesii, Bromus orcuttianus var. halli, Lonicera hispidula, Chimaphila menziesii, Pterspora andromedea, and Sedum spathulifolium are all at the S. limits of their ranges within the RNA. Introduced Species: Only two introduced plant species are known to occur within the RNA: Bromus tectorum (cheatgrass) and Vulpia myuros var. hirsuta (foxtail fescue). Fire History: Much of the area within this RNA burned in August 1989. The information presented here is pre-burn data from the ecological survey. Before the fire, the area had not burned in more than 100 years and was noted for the great age of its chaparral. According to Frazier (1989) in a post-fire examination of the area, the fire did not crown the bigcone Douglas-fir, and many of those trees were doing well. However, the fire did kill most of the seedlings and saplings of both bigcone Douglas-fir and canyon live oak. Physical Characteristics The established RNA covers 480 acres (194 ha) between 3240 and 5077 ft (1311- 1547 m). The study area covers 471 acres (191 ha) between 3000 and 5077 ft (900-1550 m). The highest point of the Agua Tibia mountains, Eagle Crag, is included in the RNA (fig. 6). The Agua Tibia Range divide passes through this crag, separating the RNA into a less eroded, W.-facing slope and a N.-facing 14 USDA Forest Service General Technical Report PSW-GTR-188. 2004. 2.Agua Tibia slope cut by several minor drainages.