Abstract: By using Granier’s thermal dissipation probe, the sap flow of 14 sample trees i n a 22-year old Acacia mangium forest in hilly land of South China was continuo usly measured in 2004. Environmental factors including the photosynthetically active radiation, air temperature, and air humidity above canopy and the water content in 0〖KG-*2〗- 〖KG-*7〗30 cm soil layer were monitored simultaneously. Combining with the tree morp hological features and sap flux density, the whole-tree transpiration, canopy s tomatal conductance, and ratio of leaf area to sapwood area were calculated by s implified Whitehead and Jarvis equation, and the effects of tree height on these three parameters were analyzed. The results indicated that under sufficient soi l water supply, the whole-tree transpiration increased in a quadratic polynomial way with tree height (P<001), and the diurnal variation of canopy stomatal conductance was of one-peak pattern. Within the measured range of photosynthetically activ e radiation, taller A. mangium trees had higher reference canopy stomatal conduc tance and higher sensitivity of canopy stomatal conductance to vapor pressure de ficit, compared with the shorter ones. The ratio of leaf area to sapwood a rea was (1837±0048) m2·cm-2, and increased in power function with tree height. A. mangium had no obvious hydraulic limitation and compensation eff ect with its increasing tree height.

Key words: migration, invertebrate, bay, bivalve, spawning bed, seed bed