Record mining of cherry flowering phenology in Tokyo during the Meiji and Taisho eras from Atomi Kakei's diary

Abstract

To evaluate the long-term relationship between climate change and plant phenology in spring, record mining of cherry flowering phenology before the Japan Meteorological Agency began recording phenological observations is an important task. We retrieved records of flowering phenology during the Meiji and Taisho eras from the diary of Atomi Kakei, a Japanese educator (1840−1926) and then evaluated the data quality and systematic errors. We were able to retrieve 22 years of flowering dates and 33 years of full-bloom dates across the period from 1873 to 1924. The flowering and full-bloom dates retrieved from this period were about 10 days later than those at present. The records of cherry flowering phenology in the diary may be considered to contain systematic errors of at least a few days caused by the differences of observation points and persons, discrete observation days, and differences of cherry species and individual trees but our findings indicated that diary records of the phenology of cherry flowering is useful for determining the phenological effects of climate change.