Carbon Balance and Management

Background: Coarse and fine woody debris are substantial forest ecosystem carbon stocks; however, there is a lack of understanding how these detrital carbon stocks vary across forested landscapes. Because forest woody detritus production and decay rates may partially depend on climatic conditions, the accumulation of coarse and fine woody debris carbon stocks in forests may be correlated with climate. This study used a nationwide inventory of coarse and fine woody debris in the United States to examine how these carbon stocks vary by climatic regions and variables. Results: Mean coarse and fine woody debris forest carbon stocks vary by Köppen's climatic regions across the United States. The highest carbon stocks were found in regions with cool summers while the lowest carbon stocks were found in arid desert/steppes or temperate humid regions. Coarse and fine woody debris carbon stocks were found to be positively correlated with available moisture and negatively correlated with maximum temperature. Conclusion: It was concluded with only medium confidence that coarse and fine woody debris carbon stocks may be at risk of becoming net emitter of carbon under a global climate warming scenario as increases in coarse or fine woody debris production (sinks) may be more than offset by increases in forest woody detritus decay rates (emission). Given the preliminary results of this study and the rather tenuous status of coarse and fine woody debris carbon stocks as either a source or sink of CO2, further research is suggested in the areas of forest detritus decay and production. Background Estimation of carbon sequestration using large-scale forest inventory data has become important due to the link between possible climate change and the accumulation of greenhouse gases in the atmosphere [1,2]. In 1992, 150 countries including the U.S. signed the United Nations Framework Convention on Climate Change that resulted in the development of annual reports of greenhouse gas inventories including carbon in forests. Forest carbon pools are often delineated as standing live trees, standing dead trees, down and dead woody materials, forest floor, understory, and soils. The down and dead woody materials pool (detritus) essentially consists of coarse woody debris, fine woody debris, and stumps. Coarse woody debris is defined by the Forest Inventory and Analysis (FIA) program of the USDA Forest Service as down and dead woody material at least 7.62 cm in diameter [3]. Fine woody debris is defined by FIA as dead and down woody material with a diameter between 0.01 and 7.61 cm [3]. In the U.S., it has been estimated that 35 % of the total forest Published: 9 June 2008 Carbon Balance and Management 2008, 3:5 doi:10.1186/1750-0680-3-5 Received: 28 March 2008 Accepted: 9 June 2008 This article is available from: http://www.cbmjournal.com/content/3/1/5 © 2008 Woodall and Liknes; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.