Forests support the majority (ca. 70%) of terrestrial biodiversity on Earth, but the demand for economic outputs from these areas has resulted in global biodiversity decline during the Anthropocene. In particular, removal of large old trees and conversion of old growth forests into single-species, single-age plantations have degraded forests and have drawn much attention in the last 50 years. Despite decades of research, especially in the Pacific Northwest, we still do not understand how many species, taxonomic communities, and ecosystems respond to these disturbances. In this dissertation, my objective was to examine the role of disturbance and the importance of remaining old growth forests in the Pacific Northwest at multiple scales ranging from the response of a single species to a whole ecosystem. Between 2017 and 2019, I collected traditional and next generation natural history data using carnivore scats, camera traps, radiotelemetry, bulk invertebrate traps, soil cores, and observations in the H. J. Andrews Experimental Forest and the surrounding Willamette National Forest, which are located on the western slope of the Oregon Cascade Range.