Comparing strategies for representing individual-tree secondary growth in mixed-species stands in the Acadian Forest region

•This analysis developed and compared alternative approaches to update stem diameter.•Two-stage procedures (potential & modifier) were inferior to strategies predicting realized stem diameter increment.•Our study showed the efficiency and flexibility of diameter predictions by including tree species as a random effect.•The study thus offers a general framework for future analyses in mixed species forests. Tree diameter increment (ΔDBH) is a key component of a forest growth and yield model as predictions are passed to other submodels and tree-level estimates are scaled up to represent plot- and stand-level measures. A common problem faced in mixed-species stands is that ΔDBH needs to be characterized for numerous species, each with varying growth rates, shade tolerances, and competitive abilities. In addition, a variety of approaches have been used to model ΔDBH with unclear implications for general suitability for each species and overall prediction accuracy. This analysis used remeasurement data comprising 2,656,354 observations from 16,204 permanent sample plots across the Acadian Forest region of North America to develop and compare alternative approaches to estimating ΔDBH as well as stem basal area increment (ΔBA). Sixty-one species or genera including several with N