Peavine Point

The area covers 1098 acres (444 ha) of the lower west slope of the Sierra Nevada in the canyon of the South Fork of the American River. It occupies the north and south walls of the canyon. Elevations range from 2080 to 3854 ft (634-1175 m). South- and north-facing slopes are predominant and generally steep (30-40°). The river gradient in the area is about 132 ft/mile (25 m/km). One additional small, permanent stream (Soldier Creek) and an intermittent stream flow through the area.

Distinctive Features

This vegetation type is not well represented in the RNA system and is relatively scarce in the Sierra Nevada because of timber harvesting over the past 100 years. The understory of this forest has been subject to regular ground fires, typical of this association. The forest is within easy access by road.

Association Types

Ten plots were sampled.

Ponderosa Pine-Chamaebatia foliolosa (84210, 81340): 835 acres (338 ha). This is the most extensive type in the area. Ponderosa pine is the canopy dominant with California black oak as the major subcanopy species. In the establishment record, the black oak forest (140 acres [57 ha]) is separated from the westside ponderosa pine forest. Basal area on the sample plots averages 63.9 m²/ha with ponderosa pine comprising 78 percent of this value. Basal areas for ponderosa pine range from 15 to 97 m²/ha, with densities of 57-309 stems/ha (mean 169). Total stem density averages 239/ha. Other trees represented on the plots, in order of basal area cover, are canyon live oak (Quercus chrysolepis), white fir (Abies concolor), and California nutmeg (Torreya californica). Individuals of ponderosa pine are typically large with stands relatively open, but averaging high basal area. Mean dbh for sampled ponderosa pine is 23.3 inches (59.2 cm). Chamaebatia is the major understory species, often covering nearly 100 percent, but it is patchy. Ceanothus integerrimus and Toxicodendron diversilobum are also important understory shrubs. Twenty-five other herbs and shrubs are represented on the association table for this type. However, most have less than 1 percent cover. Among the most conspicuous are Lupinus latifolius, Galium bolanderi, Aster radulinus, and Lathyrus nevadensis.

Douglas-Fir-Pacific Dogwood (Pseudotsuga menziesii-Cornus nuttallii) (84230):240 acres (97 ha). Large areas of this vegetation (on north-facing slopes) occur on the south side of the river. This type also occurs on the north side of the river in small areas of north-facing slopes near Soldier Creek. Douglas-fir is the dominant tree, with white fir and incense-cedar (Libocedrus decurrens) subdominant and occasional ponderosa and sugar pines as lesser associates. California black oak (Quercus kelloggii), canyon live oak (Q. chrysolepis), Pacific yew (Taxus brevifolia), bigleaf maple (Acer macrophyllum), and Pacific dogwood (Cornus nuttallii) are common subcanopy species.

Canyon Live Oak-Arctostaphylos mewukka (81320, 37520): 20 acres (8 ha). This association is limited to rocky sites (e.g., granitic outcrops) where soil development is minimal. Canyon live oak is the principal species, often forming a partially closed canopy. Arctostaphylos mewukka is important only where the stand is open and canyon live oak density is low.

White Alder (Alnus rhombifolia)-Peltiphylum peltatum (61510): 3 acres (1 ha). This association is limited to the immediate riparian area of the South Fork of the American River below the mean high-water level. White alder is the major dominant, reaching 20 inches (50 cm) dbh and 50 ft (15 m) in height. The major conifers from the surrounding associations also occur sporadically in this type. Peltiphyllum is the dominant herb. Other species include Pacific yew, Boykinia elata, Aralia californica, Mimulus cardinalis, Athyrium filix-femina, Aquilegia formosa var. truncata, Corylus cornuta var. californica, Disporum hookeri var. trachyandrum, Rosa gymnocarpa, Adenocaulon bicolor, and Galium triflorum.

Plant Diversity

One hundred fifty-three taxa are listed.

Conflicting Impacts

No potential impacts are listed. However, without natural fire in the near future, prescribed burns will be necessary to maintain the open understory of the Pinus ponderosa forests.