A stochastic forest simulator accurately describes variation in boreal forest structure across Quebec, Canada

Improving our understanding of the dynamic links between demographic rates and forest structure is essential for accurately modelling forest responses to global change. Although individual-based modelling approaches offer a valuable means of gaining insights into the effects of growth and mortality on forest size and age structures, most require detailed physiological data that are not readily available. Here, building on previously developed stochastic growth simulations for single species, we simulate multi-species forest age and stem diameter distributions using stem diameter growth and mortality data from the Quebec provincial forest inventory program. The simulator accurately reproduces forest size and age structures derived from forest inventory and tree ring data and successfully replicates the variation in forest structure among different forest types and across latitudes. In contrast to most individual-based models, this approach does not require complex parameterization of growth functions. We anticipate that this method will have a wide range of applications in exploring the links between demographic rates, forest size and age structure, stem turnover rates, and biomass across forests globally, and by extension improve our understanding of forest dynamics in a changing world.