Compared to presettlement times, many ponderosa pine forest of the United States are now more dense and have greater quantities of fuels. Widespread treatments are needed in these forests to restore ecological integrity and to reduce the risk of uncharacteristically severe fires. Among possible restorative treatments, however, the appropriate balance among cuttings, mechanical fuel treatments, and prescribed fire is often unclear. Resource managers need better information on the effects of alternative practices such as fire and mechanical/manual 'fuel surrogates'. A group of scientists and land managers has designed an integrated national network of long-term research sites to address this need, with support from the U.S. Joint Fire Science Program. Seven of the 11 sites in the network are in ponderosa pine-dominated Western coniferous forests with low severity natural fire regimes. The study will assess a wide range of ecological and economic consequences of four alternative restoration treatments: (1) cutting and mechanical fuel treatments alone; (2) prescribe fire alone; (3) a combination of cuttings, mechanical fuel treatments, and prescribed fire; and (4) untreated controls. The study is long term, with treatments repeated over time. Each site will have at least three replications of the four treatments, applied to treatment units of at least 14 ha in size (including buffer). Where feasible, the replicated units will be supplemented by unreplicated large areas treated similarly to study larger scale ecological and operational issues. A comprehensive set of core variables will be measured at each site, including aspects of fire behavior and fuels, vegetation, wildlife, entomology, pathology, soils, and economics. The core design will allow inter-disciplinary analysis at both the site and multi-site scales. Investigators at each site will also have the freedom to add treatments and/or response variables to the core design as dictated by local interests, available resources, and expertise.