LIFESCI 2H03 Study Guide - Final Guide: Prairie Pothole Region, Sulfate-Reducing Microorganisms, Arbuscular Mycorrhiza
3 Feb 2015
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Document Summary
Human activities have greatly accelerated emissions of both carbon dioxide and biologically reactive nitrogen to the atmosphere. As nitrogen availability often limits forest productivity, it has long been expected that anthropogenic nitrogen deposition could stimulate carbon sequestration in forests. However, spatially extensive evidence for deposition induced stimulation of forest growth has been lacking, and quantitative estimates from models and plot- level studies are controversial. Here, we use forest inventory data to examine the impact of nitrogen deposition on tree growth, survival and carbon storage across the northeastern and north-central usa during the 1980s and 1990s. We show a range of growth and mortality responses to nitrogen deposition among the region"s 24 most common tree species. Nitrogen deposition (which ranged from 3 to 11 kg ha 1 yr 1) enhanced the growth of 11 species and decreased the growth of 3 species. Nitrogen deposition enhanced growth of all tree species with arbuscular mycorrhizal fungi associations.
