Phenology of Subtropical Trees in Amami Oshima

Tree phenology is influenced by changes in photoperiod and air temperature. In autumn, tree growth declines with short photoperiod, and in winter, growth is suspended due to low air temperatures. In spring, rising temperatures trigger growth. The suspended growth in winter can resume only after a sufficient amount of cold exposure has been achieved. Hence, the progression of global warming is expected to disrupt this winter–spring phenology by increasing the air temperature during winer. This disruption may be profound in the subtropical zone, where winters are mild. However, knowledge of winter–spring phenology in the subtropical zone is rudimentary, and this makes it difficult to predict how winter–spring phenology will be affected by global warming. The presentation discusses bud growth and its related physiology in subtropical trees growing in Amami Oshima, Japan, to provide a better understanding of winter–spring phenology in the subtropical zone.