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Master of Environmental Science and Management: Master's Group Project

Conservation of Southern California Yellow Pine Mixed Conifer Forests

ground level view of a tall pine tree


Group Project Proposal

Final Report

Executive Summary

Final Presentation


Yellow pine mixed conifer (YPMC) forests, which provide important ecological, economic, and social benefits, are the most abundant conifer forest habitat type in Southern California. 1 However, anthropogenic impacts like fire suppression, cessation of Native American burning, and climate change threaten the health and continued persistence of these forests and the benefits they provide by increasing fire severity, habitat loss, and bark beetle mortality. YPMC forests in Southern California are “sky islands” that are geographically isolated among many different mountain ranges. 2 This makes these forests sensitive to severe perturbations as there are no nearby seed sources to assist in regeneration following disturbance events, nor can the forests shift upward in latitude to escape from stressors. Therefore, it is essential to protect existing YPMC habitat by managing for resilience to disturbances. Understanding past, present, and likely future conditions of YPMC forests will allow managers to make informed decisions to better preserve these forests for future generations.

Figure 1. Tree density of conifers and oaks by size class. Conifers and oaks included in the analysis include: Abies concolor (white fir), Calocedrus decurrens (incense cedar), Pinus coulteri (Coulter pine), Pseudotsuga macrocarpa (Bigcone douglas-fir), Pinus lambertiana (sugar pine), Pinus jeffreyi (Jeffrey pine), and Pinus ponderosa (Ponderosa pine), Quercus chrysolepis (canyon live oak) and Quercus kelloggii (black oak).


USFS: Gabrielle Bohlman, Associate Ecologist; Sarah Hennessy, Ecologist

Bren School: Frank Davis, Professor; Allison Horst, Lecturer; Ashley Larson, Assistant Professor

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