Is pollen limited? The answer is blowin' in the wind

Pollen from wind-pollinated trees has traditionally been assumed to be abundant and to travel long distances, resulting in extensive gene flow. However, recent empirical work by Knapp et al, genetic analysis by Sork et al, and theoretical models by Satake and Iwasa conclude that short-distance dispersal of limited pollen might be common and play an important role in causing the highly variable seed production (masting) frequently observed in such species. Pollen movement might be sufficiently restricted that increased fragmentation could ultimately bring about reproductive failure in some species.