Many U. S. forests, especially those with historically short-interval, low- to moderate-severity fire regimes, are too dense and have excessive quantities of fuels. Widespread treatments are needed to restore ecological integrity and reduce the high risk of destructive, uncharacteristically severe fires in these forests. Among possible restorative treatments, however, the appropriate balance among cuttings, mechanical fuel treatments, and prescribed fire is often unclear. For improved decision making, resource managers need much better information about the consequences of alternative management practices involving fire and mechanical/manual 'fire surrogates.' A group of scientists and land managers is designing an integrated national network of long-term research sites to address this need, with support from the U. S. Joint Fire Science Program. Most of the 11 sites in the proposed initial network are located in western coniferous forests, with a smaller number in southern pine and central hardwoods. All sites to date are in those high priority forests with low-severity natural fire regimes. The proposed research is intended to assess a wide range of ecological, economic, and social consequences of several alternative fire hazard reduction and 'forest health' treatments: (1) cuttings and mechanical fuel treatments alone; (2) prescribed fire alone; (3) a combination of cuttings, mechanical fuel treatments, and prescribed fire; and (4) untreated controls. Consistent with the long-term nature of the study, non-control treatments will be repeated over time. Each research site will include 3 or more replications of these 4 core treatments. Each treatment plot will be approximately 14 ha in size (including buffer). Where feasible, these relatively small replicated plots will be supplemented by much larger (200 to 400 ha or more), generally unreplicated areas treated to the same specifications, to facilitate the study of larger-scale ecological and economic/operational questions. Valid results at each site and meaningful comparisons across sites will be enabled by a common or 'core' research design, one key aspect of which is a large set of core response variables and measurement protocols. Core variables encompass several broad disciplinary areas, including fire and fuels, vegetation, wildlife, entomology, pathology, soils/hydrology, utilization/economics, and social science. Investigators at each site will have the freedom to add treatments and/or response variables to the core design as appropriate to local interests and available resources and expertise. The steering group and other participants in the study represent a number of federal and state agencies, universities, and private entities.