Realistic modelling of the topological development of a tree stand is difficult owing to the variability of branching patterns. Using data from Mongolian Scots pine, Pinus sylvestris var. mongolica, Wang et al. introduce a new protocol for the parameterisation of the stochastic version of GreenLab model, GL2, that considers the effects of random topological development on plant function. The work paves the way for making a bridge between single-plant and stand models for characterising tree structures and biomass allocation.