To evaluate whether the reproduction signal affects the seasonal pattern of radial growth in tree species or not, high-resolution radial growth was monitored using the digital dendro - meter in 17 trees of Fagus crenata on the side slope of Mt Naeba. The monitoring was conducted from early spring 2014 when the forest floor was covered with snow deeply and the winter bud of F. crenata had not opened yet (early-April) until the end of the growing season (middle-October). The radial growth started at the almost same time just after leaf flash (in late May). It continued in various periods among trees and stopped by late July – early September. Neither flower bud initiation for the following year (2015) nor reproduction in the previous year (2013) could explain the variation of the radial growth period clearly. However, when the individual tree effect was considered with the data in the previous year, the radial growth periods of trees that did not have flower bud for the following year showed shortened trends compared to those of trees with flower bud. The relationship between the flower bud initiation and the radial growth period would be discussed.