Role of gap dynamics in the evolution of masting of trees

Question: When should masting (the intermittent and synchronized reproduction of forest trees) evolve? Mathematical models: The resource budget of each tree is traced. Trees need outcross pollen to produce fruits, and trees within an entire forest exchange pollen with each other (global pollen coupling). The forest is composed of a number of sites. Each site can lose its trees, after which it becomes a gap, available for recruitment from seeds. Model analysis: We developed a new graphical method called the finite pairwise invasibility plot (fPIP), which shows whether a mutant phenotype has a fixation probability higher than the neutral case. We search for the evolutionary outcome in a finite population. Conclusion: In the absence of seed predators, trees will evolve masting only if it improves their pollination efficiency. In addition, (1) empty sites (gaps) need to remain empty over multiple years, and (2) pollen limitation must be severe in non-mast years.