元谋干热河谷地区新银合欢天然更新的初步调查

通过2005年6和10月对元谋干热河谷地区新银合欢人工林的调查,发现新银合欢林下幼苗数量较多,经过对幼苗刨根后,发现林下的新银合欢幼苗均为种子实生苗,表明新银合欢是通过种子繁殖来完成天然更新。新银合欢单株结实量在602~1513粒,树体高大的结实量多;其林下幼苗生长良好,更新密度最低为368株·m-2,最高达960株·m-2;新银合欢林缘幼苗最远扩散距离为58·3m,幼苗的扩散范围主要集中在距离林缘10m的区域内,种子受风力和流水的影响,可以沿沟谷传播很远。

Natural regeneration of Leucaena leucocephala in Yuanmou dry-hot valley

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.