Forested Communities of the Upper Montane in the Central and Southern Sierra Nevada

Abstract

Potter, Donald A. 1998 Upper montane forests in the central and southern Sierra Nevada of California were classified into 26 plant associations by using information collected from 0.1-acre circular plots. Within this region, the forested environment including the physiographic setting, geology, soils, and vegetation is described in detail. A simulation model is presented for this portion of the Sierra Nevada that refines discussions of climate, and disturbance regimes are described to illustrate the interaction between these features of the environment and vegetation in the study area. In the classification, plant associations are differentiated by floristic composition, environmental setting, and measurements of productivity. Differences in elevation, aspect, topographic setting, and soil properties generally distinguish each plant association described. A detailed description is presented for each plant association, including a discussion of the distribution, environment, vegetation, soils, productivity, coarse woody debris, range, wildlife, and management recommendations. A complete species list and tables for cross referencing specific characteristics of each association are provided.

Changing forest structure across the landscape of the Sierra Nevada, CA, USA, since the 1930s

“…The percent of precipitation that falls as snow varies from 0% near the valley floor, to around 90% near the crest. January mean minimum temperatures range from 38 to 48C at the lowest elevations (Central Valley) to below À158C at elevations above 3000 m; July mean maximum temperatures range from about 358C in the Central Valley, to ,208C above 3000 m (SNEP 1996, Potter 1998, Storer et al 2004.…”

“…A veneer of Late Cenozoic volcanic rocks overlays the basement rocks in much of the northern portion; granitic rocks dominate in the southern half of the study area. Soil types across the study area are highly diverse (SNEP 1996, Potter 1998, Storer et al 2004, Hill 2006. Nearly two-thirds (64%) of land in the Sierra Nevada is publicly owned (36% private), 41% by the US Forest Service, 13% by the Bureau of Land Management and 6% by the Park Service.…”

Evolving paradigms of aspen ecology and management: impacts of stand condition and fire severity on vegetation dynamics

“…Average yearly, January, and July temperatures were approximately 28, À5.58, and 118C, respectively, during this measurement period. Soils are weakly developed and well-drained decomposed v www.esajournals.org granite Entisols (Potter 1998). Aspen are often associated with riparian areas or mesic sites with low slope angle, though upland stands are also present.…”

“…This may have v www.esajournals.org been the last major window of regeneration for Sierran aspen, as the 20th century marked the onset of extensive areas of fire suppression ) and reduced human disturbance. As a result, the predominantly seral aspen stands in the Sierra Nevada ) are often of advanced age and well along in the process of succession to conifers (Potter 1998). As a result, there has been a major effort to assess the conditions of current stands to identify those that are at the highest risk of being lost, indicated by a high level of conifer encroachment, major component of sagebrush understory, inadequate regeneration, and/or high levels of disease (Burton 2004).…”

Ecosystem responses to elevated CO<sub>2</sub> using airborne remote sensing at Mammoth Mountain, California

“…Mammoth mountain is an upper montane forest ecosystem, characterised by abundant Pinus contorta (lodgepole pine), and also by mature stands of Abies magnifica (red fir), Pinus jeffreyi (Jeffrey pine), Pinus albicaulis (whitebark pine), and Juniperus occidentalis (western juniper) (Potter, 1998). The elevation of our study areas ranged from 2700 to 2950 m. Treekill soils are immature High Sierra soils formed from granite, pumice, rhyolite, and obsidian 15 parent materials (McGee and Gerlach, 1998).…”