Ownership patterns drive multi-scale forest structure patterns across a large landscape in southern coastal Oregon, USA

Abstract

Globally, the physical structure of forests results from their environmental setting, disturbance history, and human management practices. Human management practices today arguably have the greatest impact on the types and patterns of forest structure through direct management and modification of disturbance regimes. Previous studies have found that land ownership affects forest cover, patch dynamics, structure, and ecosystem function and services. However, these assessments of forest structure across landscapes and ownerships have been limited by the availability of high-fidelity data across a large spatial extent. To expand upon prior research, I used airborne lidar to assess the multi-scalar patterns of forest structure across a large (471,000 hectare), multi-owner landscape of the Oregon Coast Range. I examined forest structure patterns by identifying six statistically distinct classes of forest structure and then examining their distribution across and within ownership types. I used these structure classes to examine their area within each ownership class, mean patch size, and intermixing at multiple scales. I found that the six different forest structure classes in the study area can be interpreted as two assemblages, production-style forests principally on private lands and structurally complex forests principally on public lands. I found that land ownership objectives manifested in the physical landscape pattern of forest structure as measured by mean patch size and intermixing of structures. Finally, I found that landscape pattern of forest structure varied across scales as well as between ownerships. These results can be used to aid in monitoring and implementation of conservation strategies, for instance, in the monitoring of structurally complex forest and Northern Spotted Owl habitat and implementation of the Oregon Forest Practices Act.