The model generates cell dimensions of adjacent xylem radial files from simulated cambial activity in conifers. It mimics the processes of cell division, enlargement, and wall thickening during cambial activity. Each value for each of 14 variables is selected randomly from a normal population of values specified by a mean and standard deviation. Thus, 16 simulated files modeled after a real file from a Pinus resinosa annual ring differed from each other. The mean dimensions for each cell from the simulations were good estimates of radial diameters from the real file, but tended to underestimate wall thicknesses. Simulated files treated as adjacent files appeared similar to a small piece of wood in transverse section produced at any particular time during a season, but not throughout a whole season, because files often differed too much in total length. Some type of interaction between files will be necessary for modeling a segment of a complete ring.