This data set contains output from the dynamic vegetation model MC1, as modified to simulate future woody encroachment in the northern Great Plains, for 23 monthly variables, 63 yearly variables, and 31 multi-year variables. Variables include simulated plant (by growth form) and soil carbon stocks, net primary production, vegetation type, potential and actual evapotranspiration, stream flow, and fuel mass and moisture. Model output is provided for the EQ, Spinup, Historical, and Future stages of MC1 runs; future stages were run for four climate projections crossed with 10 or 11 fire X grazing X CO2 concentration scenarios for the western and eastern portions of the study area, respectively.