Abstract
Dispersal efficiency of Castanea pollen was revealed by surface and airborne pollen spectra in and around a C. crenata forest, and reconstructed distribution of the C. crenata forest in the Jomon period was discussed. In the surface pollen assemblages, C. crenata accounted for more than 60% of tree pollen in inner areas more than 25 m from the edge of the C. crenata forest, >30% in outer areas of the forest, but, outside the forest, 5% at 20 m from the edge of the tree crown, <1% at 200 m, and 2.5–5% in forests with sparse C. crenata trees. In the C. crenata forest, a small quantity of C. crenata pollen was dispersed by wind, but most accumulated on the forest floor by gravity and rain. The surface and airborne pollen spectra showed that C. crenata pollen is extremely difficult to disperse. Based on the dispersal characteristics of Castanea pollen, the distribution of C. crenata forests around the Sannai-maruyama site was reconstructed by spatial investigation of fossil pollen spectra. The distribution of Castanea pollen revealed that C. crenata forests covered most of the slopes and edges of the plateau of the Sannai-maruyama site in the late phase of the early to the middle Jomon periods.
