The northwestern U.S. during deglaciation; Vegetational history and paleoclimatic implications

Abstract

To understand the way late Quaternary environmental change has shaped vegetation requires a network of detailed paleoecologic records. In the northwestern conterminous U.S. (hereafter referred to as the northwestern U.S.) and Alaska, this is especially true, inasmuch as the habitats and biota of a mountainous area are complex. Superimposed on the geographic and ecologic diversity of these regions is a climate greatly modified by topography and highly variable through geologic time. Modernization of the vegetation in the late Cenozoic was a response to the gradual cooling of climate and to the shorter climatic oscillations that culminated with the glacial and interglacial cycles of the Quaternary. The effect of a single cycle on plant communities in the course of long-term climatic deterioration — indeed even the impact of the last glacial/interglacial cycle — is not well known.