Sugar Pine Point

The area covers 640 acres (259 ha) of a south-facing canyon slope above the North Fork of the American River. Elevations range from 4000 ft to about 6100 ft (1219- 1859 m). The area consists of a bowl-like slope with promontories extending southward on the east and west edges of the area. Small drainages and rolling topography exist in the middle of this bowl. Slopes are generally moderate within the bowl, but they drop steeply at the lower (south) edge of the area toward the riverbed.

Distinctive Features 

Succession: This study site provides numerous examples of the dynamics of mixed conifer forest succession from montane chaparral through mature stands co-dominated by several species. 

Rare Plants: Although not specifically listed from the study site, several rare plants were mapped in the vicinity of the site and may occur here. These include Cypripedium fasciculatum (CNPS List 4) and three members of CNPS List 1B: Lewisia pygmaea ssp. longipetala, Lewisia serrata, and Phacelia stebbinsii.

Association Types 

Based on 14 releves and subsequent construction of an association table, four associations were recognized. Five releves also double as sample plots where density and basal area cover for trees were recorded. 

Ponderosa Pine (Pinus ponderosa)-Sugar Pine (P. lambertiana)-White Fir (Abies concolor) (84230, 84240): 250 acres (101 ha). Eight releves are located on this association, which is dominated by the three namesake species or incense-cedar (Libocedrus decurrens), or by all four. There is a wide variation in size-class distribution and dominance, ranging from dense stands of young white fir to mature forest co-dominated by large sugar and ponderosa pines and white fir. Total basal area cover ranges from 9.7 to 110 m²/ha and tree density from 308 to 764/ha. Douglas-fir (Pseudotsuga menziesii) is occasional. Red fir (Abies magnifica) and Jeffrey pine (Pinus jeffreyi) also occur at the upper elevations. 

As a result of fire, young forest has senescent shrubs of Quercus vaccinifolia and Arctostaphylos patula, indicating past dominance by these mountain chaparral species. Shrubs vary in density and composition depending on the history of the individual plot. Arctostaphylos patula, Quercus vaccinifolia, Ceanothus fresnensis, and C. integerrimus are among the most common shrubs. Herbs also vary with plot history. Among the most prevalent are Gayophytum humile, Apocynum androsaemifolium, Pteridium aquilinum var. pubescens, Chimaphila menziesii, and Penstemon deustus.

Montane Chaparral (37510): 219 acres (89 ha). The largest portion of this association is on the steepest part of the central bowl area. This montane chaparral is maintained by fire, which carries well up the steep slopes. Typical species are the same as those shrubs listed for the ponderosa pine-sugar pine-white fir association. 

California Black Oak (Quercus kelloggii) Forest (71120, 81340): 94 acres (38 ha). California black oak is an important species of the lower elevation forests. Many California black oaks are resprouts from previous fires. Some root crowns are 3- 5 ft (1-1.5 m) in diameter. One sample stand is representative of this type and has a number of young ponderosa pine, sugar pine, incense-cedar, and white fir in it. California black oak comprises 67 percent of the basal area and 50 percent of the stems. Average stem diameter of California black oak in this stand is 6.7 inches (17 cm). 

Rocky Herbaceous Association (no Holland equivalent): In open, rocky sites the montane chaparral gives way to this type, dominated by scattered herbs and grasses. These include Poa palustris, Arabis holboellii, Penstemon deustus, Zauschneria californica, Onychium densum, Zigadenus venosus, Pterixia sp., and Sitanion hystrix.

Riparian (63500): Along the streambed of Little Granite Creek, a weakly developed riparian association occurs with such species as Acer glabrum var. torreyi, Spiraea densiflora, Lonicera conjugialis, Lilium parvum, Senecio triangularis, and Navarretia propinqua. 

Plant Diversity 

One hundred nine taxa are listed. 

Conflicting impacts 

None are mentioned. However, the area is surrounded by private land, necessitating unnatural boundaries to the RNA.