Leaf water storage plays a crucial role in helping young Cryptomeria japonica trees maintain their daily transpiration. Researchers found that leaves, sapwood, and elastic tissue all contribute to stored water, with leaves being the primary source. During the day, stored leaf water is used to meet transpiration demands, with replenishment occurring later in the day. Leaf water contributes significantly more to daily transpiration compared to sapwood and elastic tissue. This study highlights the importance of leaf water storage in sustaining transpiration in these trees.