Date of Graduation

Spring 5-23-2020

Document Type

Project/Capstone

Degree Name

Master of Science in Environmental Management (MSEM)

College/School

College of Arts and Sciences

Department/Program

Environmental Management

First Advisor

Stephanie Siehr

Abstract

Wildfire is a necessary part of ecosystem function in California, but fire suppression and the spread of invasive species have endangered many ecosystems. The North Coast bioregion of California has seen dramatic shifts in forest ecology and vegetative density, largely due to the disruption of historic fire regimes. Historic fire regimes were previously maintained through indigenous land management, but the arrival of European settlers in the 1850’s initiated the changes reflected in current fire regimes. Not only is the North Coast bioregion the hotbed of recent fire activity, it is experiencing decreased counts of heterogeneity within forests while also seeing increased amounts of fuel loads that contribute to more severe fires. This paper utilizes a comparative analysis of mixed conifer forest and oak woodland ecozones, describing the vegetative outcomes of their altered fire regimes. Through the synthesis of case studies, government reports, impact assessments, and management plans, I investigated the current state of these landscapes and developed recommendations for future management. The combination of fire suppression and increasing invasive populations have led to numerous shifts in forest systems. Invasive species heavily influence forest fuel loads and can change ecosystem structure, which can subsequently alter the area’s fire regime. Once a fire regime has changed it can imperil the livelihood of historic plant populations. Conifer forests are seeing shifts from resilient species to more fire-sensitive species, which can lead to the decimation of entire populations by high-severity fires. Oak woodlands are also suffering from fire regime changes, as conifers are encroaching and overtaking the forest canopy, drowning out oaks and reducing them to shrub species. Both mixed conifer forests and oak woodlands are threatened by changes in their respective fire regimes. These shifts in vegetation patterns can be amended through integrative management initiatives, notably the application of prescribed burns to aid the restoration of historical fire regimes.

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