Temporal Variation in Litterfall Production of Bruguiera Gymnorrhiza Stands on Okinawa Island, Japan

This study evaluated the litterfall dynamics of the mangrove Bruguiera gymnorrhiza along the Okukubi River, Okinawa Island, Japan. Leaf and stipule litterfalls occurred throughout the year, with respective distinct monthly patterns, and could governed by monthly day length as well as monthly maximum wind speed and monthly mean air temperature, respectively. Branch litterfall depended on monthly maximum wind speed and increased exponentially with increasing monthly maximum wind speed. Flower and propagule litterfalls might be influenced by monthly mean air temperature and monthly day length, respectively. Leaves contributed the most to total litterfall and represented 71.0 and 68.7% of total litterfall in the first and second years, respectively. Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Bruguiera gymnorrhiza showed a positive correlation between leaf production and reproductive organ production.