The present distribution of Picea sect. Picea is limited in narrow areas in Honshu, although it was widely distributed during the Last Glacial Maximum Stage. To clarify distribution changes of Picea sect. Picea since the Last Glacial Age in Honshu, present distribution and cone morphology of four species, i.e., Picea alcoquiana, P. koyamai, P. maximowiczii and P. glehnii, were reviewed. Their present distribution in Honshu corresponds both with the Warmth Index of 41-45°C • month and the maximum snow depth less than 150cm. These species trend to occur on rocky sites where Tsuga diversifolia dominates and never coexist with either a montane dominant of Fagus crenata or subalpine dominants of Abies mariesii and A. veitchii. Climatic change and competition with F. crenata and Abies spp. confined the distribution of P. sect. Picea species since the Late Glacial Age. It is assumed that the P. sect. Picea had a common ancestor during the Last Glacial Maximum Stage. According to the isolation since the Last Glacial Maximum Stage, they differentiated in cone morphology resulting in the extant four different species.

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We investigated absolute number and preservation of pollen and spores in several types of forest soil. In addition, differences in preservation of pollen and spores in soil profiles were also explored. A type of forest soil, even in a warm temperate forest, possessed a large amount of pollen and spores. Pollen and spores were well- preserved in strong acid soils. Furthermore, pollen and spores in moderately moist brown forest soils (Bu) were well-preserved relatively to those in dry brown forest soils (B8 ). It is considered that absolute number and preservation of pollen and spores are influenced by soil pH and soil moisture rather than soil texture and temperature in the study sites. Pollen and spores in strong acid soils tended to be chemically oxidized and mechanically damaged rather than biologically corroded. Deterioration of major pollen grains was closely correlated with their grain size, external morphology, and exine thickness. Thus, strong acid soils may be appropriate for quantitive pollen analysis, if distortion derived from different types of pollen deterioration is corrected.

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