Across the Pacific Northwest of North America, conservation of stream quality is of considerable concern given the presence of culturally, economically, and ecologically important Pacific salmon and trout. Retention of forest stands directly adjacent to stream networks is integral to maintaining quality fish habitat as riparian forests provide a host of benefits to aquatic systems. The increasing uptake of airborne laser scanning (ALS) and other datasets from remotely piloted aircraft systems (RPAS) into natural resource management plans offers scalable, adaptable, and repeatable information on riparian forest structure and function. The primary objective of this dissertation is to assess the ability of multi-platform laser scanning and thermal data to characterize riparian forest attributes of structure and function in fisheries sensitive watersheds. To accomplish this, I used watershed-wide ALS data to distinguish which vegetation structural metrics enable discernment of riparian forests from upland forests and to develop a model of riparian probability in undisturbed stands. Additionally, I modelled riparian functional elements (RFEs) that are important for management considerations using these same ALS vegetation metrics. The distribution of the riparian probability and RFE predictions were examined in relation to the geographic extent of current riparian management areas. I then furthered the assessment of stream shading influence to stream temperature by linking lidar-derived solar insolation from RPAS lidar. I created simulations of riparian harvesting and future stand conditions to examine how current forest management practices could impact insolation, and therefore stream thermal regimes, under current and future climate scenarios. The research in this dissertation expands our understanding of riparian forest characteristics and functions in order to inform sustainable forest management practices for fisheries sensitive watersheds.
Leanna A. Stackhouse (2026) studied this question.