千岛湖消落带水位变化对池杉人工林生长的影响

Influence of Water Level Change on Growth of Taxodium ascendens Plantation at Fluctuation Zone in Thousand Island Lake

1992年2月用3年生池杉（Taxodiumascendens）大苗在海拔102.3~103.5m的浙江省淳安县界首林场坡积土消落带人工造林，2016年3月在固定样地对池杉生长情况进行调查。结果表明，造林保存率达81.0%，平均树高11.36m，5株优势木平均高14.86m，最高达15.5m，平均活枝下高3.04m，平均胸径25.95cm，最大胸径37.0cm，平均冠幅24.42m2，树冠浓荫密闭，成为了一片水上森林。1992-2015年千岛湖水位统计显示，种植后的前4a曾遭受没顶水淹，后期每年树干承受浸水深度5m，4m，3m，2m，1m分别为4d，15d，26d，58d，平均151d的树干水淹，214d露出水面。每年立地经受干与湿两个较为极端的交替控制，池杉仍能良好生长，说明池杉完全适应千岛湖海拔102.3~103.5m消落带的生长。

In February 1992, 3-year Taxodium ascendens saplings were planted at water level fluctuating zone (WLFZ) of Thousand Island Lake with the elevation 102.3m-103.5 m, Chunan county, Zhejiang province. Investigations were conducted in 2016 on permanent sample plot. The results showed that conservation rate was 81.0%, with average height of 11.36 m, average height of 5 plus individuals of 14.86 m, the highest of 15.5 m.Average clear bole height was 3.04 m, average DBH 25.95 cm, the largest DBH 37.0 cm, and average crown diameter was 24.42m2. Statistical of water level changes of the Thousand Island Lake during 1992-2015 demonstrated that the first four years of the plantation was submerged by water flooding some days, and later, trunks were meanly submerged under 5m of water for 4 days, 4 m for 15 days, 3m for 26 days, 2 m for 48 days, and 1 m for 58 days each year. The plantation went through dry and wet season each year, with good growth, indicating that T. ascendens could adapt to water level fluctuating zone in Thousand Island Lake.