Natural hybridization is attracting much interest in modern speciation and conservation biology studies, but the underlying mechanisms remain poorly understood. In particular, it is unclear why environmental changes often increase hybridization rates. To study this question, we surveyed mating events in a mixed oak stand and developed a spatially-explicit individual-based hybridization model. This model, where hybridization is frequency dependent, pollen is non-limiting and which allows immigrant pollen to compete with local pollen, takes into account...