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

卡尔霍恩实验森林的研究调查了森林生态系统发展40多年来土壤生物地球化学变化的速率和过程。从这项工作可以清楚地看出，土壤是生态系统的动态组成部分，对生态系统的变化具有显著的响应。LTREB继续进行这项研究将允许继续测试假设和目标，这些假设和目标将共同为该站点的研究发展带来关键的连续性。这三个假设涉及：(1)森林发展40年来土壤微量养分的耗竭和再补给；(2)土壤SO4以及SO4是否在过去20年中以表明空气污染输入减少的模式减少；(3)最近土壤和整个生态系统对碳14C和氮的封存的变化。最近树皮甲虫、冰和风害的干扰使叶面积减少了50%。增加森林地面凋落物的输入，并大大加速林下阔叶林的生长。由于卡尔霍恩档案馆几乎有1962年以来收集的所有土壤样本，调查人员有能力对土壤和生态系统的生化变化进行回顾性分析。该项目还包括一个面向本科生和高中生的教育推广计划，以及数据管理的改进，以扩大Calhoun数据对当前和未来研究人员的使用。

Richter0129383Research 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.