This data set contains destructively sampled canopy fuel and tree biomass data from five study sites in the Interior West. We destructively measured canopy fuels in five conifer stands in conifer forest types important to land managers in the western USA, including ponderosa pine/Douglas fir in western Montana, lodgepole pine in central Montana, Douglas fir/lodgepole pine in Idaho, ponderosa pine in Arizona, and mixed conifer in the Sierra Nevadas in California. In each of these stands we established a 10 or 15 meter radius circular plot (depending on tree density), deliberately selecting plots in dense, crown-fire-prone areas, inventoried all trees within the plot including understory trees at least 0.3 meters (1 foot) tall, and then took apart the trees branch by branch to obtain biomass by size class and component (live or dead). For every branch, we measured green weight, length, and branch basal diameter. A subportion of the branches were destructively sorted by size class, so that biomass was weighed for foliage, and live and dead woody material 0-3 millimeters (mm), 3-6 (mm), 6-10 (mm), 10-25 (mm) and 25+ (mm) in diameter. A subportion of this material was oven dried to determine moisture content and correct the measurements to dry weight. These data were then used to develop regression equations to predict oven dry biomass by size class based on branch length and basal diameter. The equations were used to estimate biomass by size class for every branch in the stand. We chose dense stands that local land managers judged to be of high crown fire potential. A number of separate files are included, containing information on surface fuels, plot data, tree data and branch data.