Abstract
It is possible to predict the day on which sugi (Cryptomeria japonica D. DON) pollen dispersal will begin by comparing the accumulative incubation temperatures for the blooming of sugi male flowers and the cumulative thermal constants calculated by temperature. After the incubation of the male flowers, the physiological characteristics of sugi were examined. Cumulative temperatures for the blooming of sugi gradually decreased after early November. With the end of January, the cumulative temperature for blooming is in reverse proportion to the cumulative thermal constant. Therefore, it is possible to predict the day on which sugi pollen dispersal will begin by comparing the accumulative incubation temperature for the blooming of male flowers collected after the end of January and the cumulative thermal constants calculated by the temperature after incubation of the male flowers.
