Reading Between The Branches: Mapping The Spatial Distribution of Tree Mortality in Blue Oak Woodlands at River Ridge Ranch, CA

Keywords: Blue Oak Woodlands, Mortality, Sierra Nevada, Landscape Ecology, GIS
Abstract Type: Paper Abstract

Abstract

The spatial distribution of oak woodlands in the Sierra Nevada foothills has been strongly influenced by its Mediterranean climate, local topography, wildfire regime change, and history of human activity. Ranchers and researchers alike are concerned with the implications from California’s recent drought (2011 - 2017) on the health of oak woodlands. Studies have clearly demonstrated a lack of recruitment and regeneration of oaks needed to sustain these populations. The threat of increased intensity and duration of warm temperatures throughout the Sierra Nevada has been correlated with the restructuring of this woodland’s composition, most notably the increase in vegetation mortality. This study seeks to measure the amount of dieback from 2018-2022 across River Ridge, a seven-hundred-acre conservation ranch in Tulare County, CA. Additionally, we aim to map the spatial distribution of oak mortality to understand how topographic features within the ranch is influencing its distribution. Building upon previous mortality mapping efforts, northern-facing slopes and locales where the density of oaks is low is expected to have less mortality relative to southern-facing slopes and locales where density is higher from this past drought.