Measuring And Modeling Carbon Stock Change Estimates For Us Forests And Uncertainties From Apparent Inter-Annual Variability

Our approach is based on a collection of models that convert or augment the USDA Forest Inventory and Analysis program survey data to estimate all forest carbon component stocks, including live and standing dead tree aboveground and belowground biomass, forest floor (litter), down deadwood, and soil organic carbon, for each inventory plot. The data, which include estimates of forest area, can then be used in calculations for total stocks or change. We describe our approach, which has been used to estimate forest carbon stocks and stock change for the annual US greenhouse gas inventory compiled by the USEPA for reporting to the United Nations Framework Convention on Climate Change. Results in the national stock change trends can exhibit relatively large annual changes in these change trends, which are called inter-annual variability. We examine the inter-annual variability and underlying data for the possible causes, and discuss implications.