Abstract
It is desirable if we can forecast the seed crop of beech forests for successful regeneration or wildlife management. Prediction method of seed crop had already been proposed in Hokkaido, in which two conditions were required for good crop, i.e. mass flowering (> 500 of flowers/m^2) and more than 20 times of increase from previous year in flower production to escape from natural enemy. Above conditions cannot be identical in Yamagata, because climatic condition and abundance of natural enemies may be different from those in Hokkaido. Matsui et al. (2009) had already pointed out that conditions for good seed crop in Yamagata would be more than 350 female flowers/m^2 and more than 10 times of flowers than those of the previous year. However it has been regarded less reliable due to the short period of investigation. In this study, we added data from other study sites and years and re-evaluated the Masui's method. Seed trap census revealed that the Matsui's method is valid to predict the seed crop in Yamagata. In addition, when a beech forest produced more than 350/m^2 of flowers, it would simultaneously satisfied the another condition. This means if only we can estimate flower production of next year by shoot sampling and flower bud observation, prediction of next year's crop is possible. Without traps, this method can be more convenient and versatile tool.
