Comparisons of allometric and climate-derived estimates of tree coarse root carbon stocks in forests of the United States
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Carbon Balance and Management. 10(1): art 20. http://dx.doi.org/10.1186/s13021-015-0032-7
Background: Refined estimation of carbon (C) stocks within forest ecosystems is a critical component of efforts to reduce greenhouse gas emissions and mitigate the effects of projected climate change through forest C management. Specifically, belowground C stocks are currently estimated in the United States' national greenhouse gas inventory (US NGHGI) using nationally consistent species- and diameter-specific equations applied to individual trees. Recent scientific evidence has pointed to the importance of climate as a driver of belowground C stocks. This study estimates belowground C using current methods applied in the US NGHGI and describes a new approach for merging both allometric models with climate-derived predictions of belowground C stocks. Results: Climate-adjusted predictions were variable depending on the region and forest type of interest, but represented an increase of 368.87 Tg of belowground C across the US, or a 6.4 % increase when compared to currentlyimplemented NGHGI estimates. Random forests regressions indicated that aboveground biomass, stand age, and stand origin (i.e., planted versus artificial regeneration) were useful predictors of belowground C stocks. Decreases in belowground C stocks were modeled after projecting mean annual temperatures at various locations throughout the US up to year 2090. Conclusions: By combining allometric equations with trends in temperature, we conclude that climate variables can be used to adjust the US NGHGI estimates of belowground C stocks. Such strategies can be used to determine the effects of future global change scenarios within a C accounting framework.
KeywordsBelowground biomass; Carbon accounting; Carbon-climate; Root:shoot ratio; Forest Inventory and Analysis
Russell, Matthew B.; Domke, Grant M.; Woodall, Christopher W.; D'Amato, Anthony W. 2015. Comparisons of allometric and climate-derived estimates of tree coarse root carbon stocks in forests of the United States. Carbon Balance and Management. 10(1): art 20. http://dx.doi.org/10.1186/s13021-015-0032-7