Globally, forests provide numerous economic, ecological, social, and cultural services to people; fostering abundant and diverse biological communities. To weigh different land management decisions, models and simulations can be used to assess how various options will alter forest dynamics. To ensure that simulations are as representative as possible, models must be tested rigorously and regularly against known landscapes. These models sometimes depend on understanding the age of individual trees or of species cohorts, however this is a difficult metric to acquire for large landscapes because accurately determining the age of trees is laborious. The LANdscape DIsturbance and Succession (LANDIS-II) model simulates forest dynamics in species-age cohorts rather than individual stems. As a cohort model, LANDIS can simulate spatial ecological processes and patterns such as succession, growth, seed dispersal, harvesting, insect herbivory, and disease for large landscapes. However, without testing how methods of modeling tree age can differently represent cohorts, we do not know the impact on simulation results. In this study, we examine the impact of different cohort age bin configurations on the representativeness of LANDIS simulated biomass. We found that LANDIS was most representative when binning cohorts with 3 to 5 age bins rather than 7 to 9. Our results stem from a series of test simulations of a single plot, and suggest that these findings should be examined at a larger scale to support their effect.