LTREB: Five Decades of Biogeochemical Change in Soils and Ecosystems of an Old-Field Forest

Duke University, Durham NC

Investigators

Abstract

Richter 0129383 Research at the Calhoun Experimental Forest has investigated rates and processes of soil biogeochemical change over four decades of forest-ecosystem development. From this work it is clear that soils are dynamic components of ecosystems remarkably responsive to ecosystem change. Continuation of this study by LTREB will allow continued testing of hypotheses and objectives that together will result in critical continuity for research development at this site. The three hypotheses concern: (1) the depletability and resupply of soil micronutrients over four decades of forest development, (2) soil SO4 and whether SO4 is decreasing in the last two decades in a pattern indicative of reduced air-pollution inputs, and (3) recent changes in soil and whole-ecosystem sequestration of C 14C, and N. Making this particularly compelling is the recent disturbance by bark beetles, ice and wind damage which together have decreased leaf area by as much as 50%, increasing litterfall inputs to the forest floor, and greatly accelerating growth of understory hardwoods. Because the Calhoun archive has nearly all soil samples collected since 1962, investigators have the ability to conduct retrospective analyses on soil and ecosystem biochemical change. The project also includes a program of educational outreach with undergraduate and high school science students, and data management improvements to expand the use of the Calhoun data for current and future researchers.