Introduction

Consistent geospatial information characterizing effects of large wildland fires does not exist for lands within the United States. Changing trends in fire frequency, severity, and size have resulted in the need to acquire data and develop information that can establish a baseline for trend analysis and begin to look at recent historical shifts in these fire characteristics. Furthermore, there is a need to understand the impacts of fire and resource management policies on fire occurrence and severity (Stephens and Ruth 2005). These needs are recognized across agencies and at various levels within land management organizations. Moreover, the general public is increasingly exposed to information suggesting that increases in uncharacteristic fire are due in part to past land management practices. It can be assumed that public interest in current and future fire policy will increase.

The Wildland Fire Leadership Council (WFLC), a national level interagency body with responsibility for implementing and coordinating the National Fire Plan (NFP) and Federal Wildland Fire Management Policies (http://www.fireplan.gov/), has adopted a strategy to monitor the effectiveness and effects of the National Fire Plan and the Healthy Forests Restoration Act (HFRA). One component of this strategy is to assess the environmental impacts of large wildland fires and identify the trends of fire severity on all lands across the United States (WFLC 2004 Monitoring Proposal, Module 2.1). In 2004, the Government Accountability Office recommended that the Forest Service and Bureau of Land Management develop and implement comprehensive assessments of fire severity to provide consistent summary information characterizing the environmental effects of wildland fires and to meet the requirements of WFLC.

Beyond the needs of WFLC, it is widely recognized that nationally consistent and current data are necessary to address issues of ecosystem health and sustainability. The National Report on Sustainable Forests (2004) describes criteria and indicators that are an important framework for sustainable management. Whereas the report does not specifically address the need for fire occurrence and effects data, it is easy to see both the direct and indirect relationships that exist between these criteria and indicators and the understanding of spatial pattern, magnitude, and frequency of fire in ecosystems across the United States. Specifically, the criterion addressing the maintenance of forest ecosystem health and vitality and the criterion addressing maintenance of forest contribution to global carbon cycles are sensitive to the spatial and temporal variability of fire effects and the gradient of change in forest ecosystems.