Permalink : http://hdl.handle.net/2115/36688

Four pollen traps at different levels were used in a natural broad- leafed forest near Tomakomai, central Hokkaido, to investigate pollen incidence and wind transport. The trap at trunk level captured a lesser amount of pollen than the other traps. The pollen period of the canopy trees was from March to the middle of June and it was characterized by a gradual increase in amount of pollen but a sharp decrease. Among the canopy trees, Carpinus, Quercus, Alnus, Betula and Cryptomeria showed the highest pollen frequency. Pollen transported into the sampling site were those of Crypromeria, Fagus, Aesculus Castanea and Tsuga. Although Cryptomeria pollen accounted for 38-48% of the total amount of the canopy tree pollen in the middle of April 1978, the nearest Cryptomeria-bearing forest is about 16 km west of the sampling site.