Historic and Simulated Vegetation Dynamics in Former Oregon White Oak Savanna, Southern Willamette Valley, Oregon, USA

Abstract

Oak savanna was once widespread throughout the Willamette Valley, but changes in land use and disturbance regimes have degraded or destroyed most of that habitat. To identify how succession has operated in the past, I calculated tree growth rates. To assess the potential fire behavior in different successional communities, I collected data on vegetation and fuels, which I then used in a fire model. Finally, to project how succession may affect vegetation in the future and the potential for oak savanna conservation and restoration, I developed a new vegetation model that allows for projections of successional dynamics that are sensitive to change in climate, fire regimes, and human land-use and land-management decisions. Results highlight the complex and nuanced influences of environmental variables on successional trajectories and potential fire behavior. The novel vegetation model showed complex and plausible vegetation dynamics across a wide range of climate and disturbance scenarios.

This dissertation includes previously published and unpublished co-authored material.