Biogeochemical hotspots around bark-beetle killed treesThis article is part of a larger document. View the larger document here.
Disturbance-induced mortality events in forest ecosystems generate significant hotspots in biogeochemical cycles. These events occur sporadically across the landscape and contribute to large sources of error in terrestrial biosphere carbon models, which have yet to capture the full complexity of biotic and abiotic factors driving ecological processes in the terrestrial environment. The balance between production of stable soil organic matter and respiration from decomposing biomass greatly influences whether temperate forests remain modest carbon sinks or are transformed into carbon sources. In 2015, a field experiment to mimic pine beetle attack was established by girdling loblolly pine trees. Subsequent measurements of throughfall and stemflow for water quantity and quality, transpiration, stem respiration, soil respiration, and soil chemistry were used to quantify the extent of spatial and temporal impacts of tree mortality on carbon budgets. Enhanced fluxes from dying trees primed surrounding soils while decreased tree water use provided additional soil moisture to create biogeochemical hotspots, which could lead to accelerated carbon decomposition and mineralization rates.