Forest Ecology and Soils

Abstract

Forests have long been managed for timber production, but more recently have started to be appreciated for the many other benefits they provide to humankind, including serving as the largest terrestrial storehouse of carbon. This article outlines some key questions related to the biogeochemical functioning of forest ecosystems that have been answered by contributions from NMR studies. These include characterization of organic matter inputs to forest soils, consisting of below-ground root inputs and above-ground plant litter materials such as leaves and woody residues. NMR also helped clarify the chemical structure of distinct organic matter pools occurring in forest soils, ranging from fresh litter and forest floor pools to stabilized organic matter. Similarly, nutrient fluxes through forest ecosystems have begun to be elucidated, thanks to NMR analyses. Finally, NMR is particularly well adapted to follow the response of forest soil organic matter to natural and anthropogenic disturbances, including fire and harvesting, and other more drastic anthropogenic influences such as open-pit mining. Taken together, the results from these NMR studies have facilitated the development of an index of forest litter quality and provided a unique insight into organic matter decomposition processes in forest soils. Future investigations combining NMR to isotopic tracing and molecular biomarker tools should allow an even better understanding of the sources, turnover rates, and stabilization processes of organic matter in these soils. Keywords: forest ecology; forest soils; soil organic matter; tracing organic matter; forest response to disturbance; solid-state 13C NMR spectroscopy