May. Chestnut pollen season extends from May to July. Facts about Beech, Chestnut, and Oak Beech trees are wind- pollinated . Beech pollen closely resembles oak pollen in morphology .
Chestnut trees are insect-pollinated.
Oaks are wind-pollinated. The pollen is very light and abundantly produced by all species. Oaks outrank any other group of trees in Missouri forests in number of species . There are about 60 species native to the United States. Beech, Chestnut, and Oak allergenicity Beech pollen plays only an insignificant role in causing hay fever.