Abstract: In this paper, an investigation was made on the Leucaena leucocephala plantations in Yuanmou dry-hot valley in June and October 2005. Under the plantations, there were a great many of seedlings, and all of them were generated from seeds, suggesting that L. leucocephala could naturally regenerate from seed. The seed quantity per tree was from 602 to 1 513, and high trees had more seeds. The seedlings were growing well, with a minimum renewal density of 960 plants per square meter and a maximum renewal density of 960 plants per square meter.The longest dispersal distance of the seedlings was 583 m from the edge of L. leucocephala stand, and the dispersal range was mostly in an area 10 m from the stand. The seeds could be dispersed to a far distance along the valley by wind and running water.

Key words: Zooplankton, Ecological characteristics, Spring, East China Sea, Red tide