Exploring forest structure patterns among ownership and federal NWFP land use allocations in the forested western Cascades of Oregon

Thesis (Master's)--University of Washington, 2021Disturbances resulting from natural forces and human intervention – such as the creation of artificial boundaries, has led to the importance in understanding the best approaches necessary for sustaining critical ecosystem functions and forest structure health. The 1994 Northwest Forest Plan (NWFP) offers an example of federal policies that consider the promotion of sustainable timber harvesting, new forest management approaches, and the protection of late successional, old growth habitats. In this study, I use airborne lidar data to develop a comprehensive high-fidelity census of forest structure patterns across a 530,817-hectare region in the NWFP allocated western Cascades of Oregon. To make sense of forest structural patterns and their arrangement across land-use allocation boundaries and ownership types, I addressed the following questions. (1) What forest structures exist across the study area and how do they correspond with commonly recognized forest development stages? (2) How are these structures distributed across ownership classes and federal administrative land use allocations? (3) 20+ years after the adoption of the NWFP, are the structurally complex forests the plan sought to protect and promote present, and if so, in what amounts and by what ownerships and administrative units? Results: (1) Six Structure classes were identified across the Western Cascades of Oregon. (2) Forest Structure classes were distributed among clusters of structurally simple and complex forest classes that created assemblages among private vs. public ownership type and Land use Allocations. (3) Hight Presence of structurally complex forest Classes were seen among NWFP Land Use Allocations