All four observation sites (Funabashi, Niigata, Fukuoka & Higashi-Osaka) for airborne pollen show some increase in the Cryptomeria japonica (Sugi) pollen count numbers, and the Funabashi site shows a notable increase during the last ten years. In 1995 the Niigata site experienced a sudden peak for the C. japonica pollen count. Following this there has been an upward tendency for slightly larger counts at this site. Generally larger peaks were also observed at the Fukuoka and Higashi-Osaka sites in 1995, although subsequent peaks have been less remarkable. For Chamaecyparis obtusa (Hinoki) pollen counts in Fukuoka exceeded 4,000/cm^2/season in 1995 with further increases in subsequent years, and maximum counts of 5,000/cm^2/season for 2005. This upward tendency of C. obtusa pollen counts is further predicted to continue in Fukuoka. Comparing these data with other sites, there were a few surprisingly high pollen counts for C. obtusa in Niigata. Where, in the 2001, a maximum peak of barely 474/cm^2/season was recorded. In Funabashi, C. obtusa pollen counts varied by about 1,000/cm^2/season until 2004, but subsequently with a highest recorded peak level of 4,000/cm^2/season in 2011. In Higashi-Osaka pollen counts for C. obtusa varied by about 1,000/cm^2/season or less but, in 1995, a sudden peak exceeded 3,000/cm^2/season, showing a notable upward tendency.

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The fossil pollen records from Koda Mire in the Kochi Plain, Shikoku, southwestern Japan, provide a vegetation history surrounding the mire during the full glacial and early post-glacial periods. Based on distribution patterns from representative pollen taxa, three local pollen assemblage zones (KD-I to KD-III) have been identified. The forest vegetation is characterized by the dominance of Quercus subgenus Quercus combined with Tsuga sieboldii, Carpinus, Fagus crenata, Betula, Acer and Corylus (KD-I: ca. 27.8-23.4 cal kyr BP), abrupt decline of T. sieboldii and some of deciduous broad-leaved taxa excluding Q. subgenus Quercus and occurrence of evergreen broad-leaved taxa (KD-II: ca. 10.1-10.0 cal kyr BP), and gradual decline of Q. subgenus Quercus and expansion of evergreen broad-leaved taxa along with Celtis and/or Aphananthe aspera (KD-III: ca. 9.5-8.4 cal kyr BP). Chronologically, zone KD-I correlates with the full-glacial period which is regarded as the cooling phase: 'Heinrich event 2' (between the Dansgaard - Oeschger cycles 3 and 2). Pollen records from Koda Mire and the adjacent area during this period indicate that mixed forest areas, comprising of temperate conifers and deciduous broad-leaved trees, were widely distributed across the Kochi Plain. Futhermore, the records suggest that it may not have served as refugia for Cryptomeria japonica and evergreen broad-leaved trees.

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