Forest Soils through Time: Change You Can Believe In!.

Our perception of the forest soil science has evolved over recent decades, as has our understanding of the importance of soils in the form and function of forested ecosystems.  This probably has had as much to do with the outreach activities of forest soil scientists as with advances in the science of forest soils.  Forest soils integrate ecosystem processes that range in temporal frequency from millennia to seconds, and the study of these phenomena captures our imagination.  I describe several examples that illustrate how forest soils shape ecosystem form and function over wide-ranging time scales.  One example provides millennial scale evidence from the first lake in Maine following deglaciation, located in Acadia National Park.  In this study, a lake sediment core provides evidence of soil biogeochemical processes that governed the evolution of this now forested watershed from deglaciation (16,600 y BP) through the Holocene.  The second example is of forest soil influences on a decadal time scale from the Bear Brook paired watershed study.  Here we test conceptual models of forest ecosystem response to experimental manipulations, and find that our understanding of both the scientific answers, and the questions, are continuously renewed.  Finally, I offer perceptions on the evolution of forest soil science.  Forest soil science has matured from an era of basic science following the revelations of Grebe (1840), to the era of Wilde (1946), where modern forest soil science in North America began.  Forest soils have become increasingly valued as the science evolved from disciplinary to inter-disciplinary, from edaphology to ecosystem services, and from forest production to acid deposition, bioenergy, carbon, and climate change.  Societal needs in the 21^st century will be unprecedented, as will be the potential for contributions from forest soil science.  We need a vision to assure that we meet this challenge.