James E. Smith1, Linda S. Heath1, Kenneth E. Skog2, and Richard A. Birdsey1. (1) USDA Forest Service, Northern Research Station, Durham, NH 03824, (2) USDA Forest Service, Forest Products Laboratory, Madison, WI 53726
We present a methodology for consistent standard forest carbon estimates adopted by the U.S. Voluntary Greenhouse Gas Reporting Program, also referred to as 1605(b). The estimates and methods also follow guidelines for reporting forest carbon as developed by the Intergovernmental Panel on Climate Change. Forests store significant quantities of carbon as they grow; factors such as forest composition or management activities can affect sequestration. Forest ecosystem carbon yield tables, representing stand-level merchantable volume and carbon pools as a function of stand age, were developed for 51 forest types within 10 regions of the United States. A portion of the carbon in forest ecosystems remains sequestered from release to the atmosphere after harvest if it is incorporated into wood products. The length of time depends on both the initial—or primary—wood products and the end-use of those products. One purpose of the standard 1605(b) estimates is to provide supplementary or default information, as needed, for reporting carbon sequestration. Detailed measurements to quantify carbon are not always feasible. Similarly, sources of information on quantities, types, and fate of harvested wood products can vary, and such information is sometimes scarce. Thus, our methods were developed as consistent estimates across scale or source of data, whether the reporting entity has detailed information on products from mills or simply the number of acres of forest in a project, for example. We apply definitions consistent with USDA Forest Service inventory and timber product datasets, explicitly account for carbon pools, and link input data to a flexible model of allocation and fate of carbon in forests and wood products. Estimates based on minimal input data reflect regional averages, and precision increases with the level of information available.