Describes a study that identified and modelled the spatial pattern of trees in lodgepole pine sites in two biogeoclimatic variants in British Columbia. The K(t) statistic was used to detect the patterns and provide a basis for determining an appropriate spatial process model. Most sites had an aggregated pattern which was modelled effectively by a Poisson cluster process. An equation describing the relationship between the parameters of the Poisson cluster process model was developed. Random patterns occurring in the plots were modelled by a Poisson process and regular patterns by a Markov point process and a lattice-based process. The appendix contains the algorithm for the processes used.