Indiana Summit

The area encompasses 1162 acres (470 ha) and ranges from 7800 to 8500 ft (2377 - 2590 m).

Distinctive Features

Extensive Virgin Jeffrey Pine Forest: The Jeffrey pine forest at Indiana Summit is part of a large tract of essentially pure Jeffrey pine forest stretching from the east flank of the Sierra Nevada across the divide between the Mono Basin and Owens River drainage. Much of this forest has been harvested for timber, and the RNA preserves a rare pristine example

First California RNA: The Indiana Summit RNA was the first RNA established in California (1932). It is cited as an example of a coniferous forest ecosystem in widely-used textbooks on ecology (Whittaker 1975) and also by the American Museum of Natural History, which has a diorama based on Indiana Summit.

Rare and Endemic Plants: Lupinus duranii, a member of CNPS List 4, is a conspicuous member of the open Jeffrey pine forest and pumice-flat area. Artemisia cana ssp. bolanderi is endemic to the Mono Basin, but not considered rare by CNPS.

Archeological Value: The Paiute Indians harvested larvae of piagi (Pandora moth [Coloradia pandora]), which cyclically attack Jeffrey pine, by digging trenches encircling the trunks of mature trees. These piagi trenches may still be seen surrounding some of the larger Jeffrey pines, although their evidence has been largely obliterated by logging and other disturbance in adjacent areas.

Rare Fauna: A prairie falcon (Falco mexicanus), State-listed as species of special concern, was seen nesting in the area in 1977 during the fieldwork for this report.

Association Types

Seven association types were defined using releves and following the construction of an association table. An additional fifteen 15-m radius plots were sampled to estimate basal area cover and stem density for forest types. Acreage is not given for all types.

Jeffrey Pine/Purshia tridentata (85100): 872 acres (353 ha). 872 acres (353 ha). Jeffrey pine is often the only conifer species in this association, but scattered lodgepole pine (Pinus contorta ssp. murrayana) occur. This is an open forest with typically less than 50 percent canopy cover. Purshia tridentata is the low shrubby dominant, covering up to 70 percent of the ground. Density of Jeffrey pine ranges from 113 to 877 stems/ha on eight plots. Basal area of Jeffrey pine ranges from 28.4 to 77.9 m²/ha. The site-index estimate for Jeffrey pine is less than 32 ft (10 m)/100 years. This low index indicates low productivity and probably low recruitment and regeneration rates. 

Herb cover is sparse with only a few species tallied. These include Carex rossii, Gayophytum diffusum ssp. parviflorum, Stipa californica, Stephanomeria tenuifolia, Lupinus duranii, Leptodactylon pungens ssp. pulchriflorum, and Linanthus nuttallii.

Lodgepole Pine/Calyptridium umbellatum (86100): 174 acres (71 ha). In this association lodgepole pine is dominant, with occasional large Jeffrey pine. The shrub layer is the most poorly developed of all the forest types. Artemisia tridentata and Purshia are predominant with a low herb cover including Calyptridium umbellatum, Chrysothamnus parryi, and Stipa elmeri. 

Lodgepole pine basal area ranges from 9.0 to 37.3 m²/ha on the four plots, and tree density ranges from 71 to 212/ha.

White Fir/Prunus emarginata (84240, 85210): 116 acres (47 ha). This type occurs on north-facing slopes. It is co-dominated by white fir and Jeffrey pine; the former species is the climax dominant. The northern exposures are moister and therefore have more shrub cover and diversity compared to the Jeffrey pine Purshia tridentata forest. The relatively deep snow pack not only provides more water with relatively low evapotranspiration rates (due to north-facing slopes), but also reduces the threat of desiccation to winter drought-susceptible species.

The basal area of white fir ranges from 27.6 to 38.5 m²/ha in three plots. Total basal area ranges from 49.1 to 80.6 m²/ha. The mean dbh of white fir is 17.3 inches (44 cm) and for Jeffrey pine, 15 inches (38 cm). Total stem density ranges from 424 to 452/ha. Sapling density (49/ha) is lower than in Jeffrey pine-dominated forest. After fire, this type becomes dominated by Artemisia tridentata/Symphoricarpos vaccinioides vegetation.

Herb cover is sparse with only occasional individuals of Bromus carinatus, Arabis holboellii var. retrofracta, Carex rossii, Poa fendleriana, and Leptodactylon pungens ssp. pulchriflorum. Shrubs include Prunus emarginata, Artemisia tridentata, Ribes cereum, Symphoricarpos vaccinioides, Ceanothus velutinus, and Chrysolepis sempervirens.

Artemisia tridentata/Symphoricarpos vaccinioides (35210): This association occupies shallow soils on steep, windswept slopes with light snow cover. It is subclimax on some sites, successional to the white fir-Prunus emarginata forest. Additional species include Ribes cereum, Ceanothus velutinus, Bromus carinatus, Purshia tridentata, Stipa californica, and Leptodactylon pungens ssp. pulchrifolium.

Haplopappus bloomeri/Gayophytum diffusum (no Holland equivalent): This is a successional type following fire in the Pinus-Purshia type. Other species include Ceanothus velutinus, Purshia tridentata, Stephanomeria tenuifolia, Eriogonum vimineum, Arabis platysperma, Eriogonum spergulinum ssp. reddingianum, Eriogonum nudum ssp. deductum, and Stipa elmeri.

Chrysothamnus parryi/Stipa elmeri (35400): This type occurs on excessively drained pumice flats. Other species contributing to the sparse cover include Artemisia tridentata, Calyptridium umbellatum, Lupinus duranii, Mimulus coccineus, Agoseris glauca ssp. monticola, Hulsea vestita, Oenothera xylocarpa, and Sitanion hystrix.

Artemisia cana ssp. bolanderi/Carex douglasii (no Holland equivalent): This type occurs in moist areas in centers of large pumice basins and around moist flats. The dominant shrub is endemic to Mono County. Additional species include Calyptridium umbellatum, Mimulus coccineus, Muhlenbergia richardsonis, Draba stenoloba ssp. nana, Juncus mertensianus, Haplopappus apargioides, Lupinus confertus, Thelypodium crispum, and Heleocharis palustris.

Plant Diversity

Seventy-three taxa are listed.

Conflicting Impacts

Tracks resulting from off-road vehicles have been observed within the RNA although disturbance is minimal. Recent woodcutting, including cutting of standing snags useful as wildlife habitat, has occurred within the RNA. These problems could be lessened if signs around the periphery of the area were maintained and increased in frequency. There has been logging on three sides of the RNA up to the boundaries.