水淹对三峡库区消落带中山杉生长的影响

The Effects of Flooding on Growth of Taxodium hybrid ‘Zhongshanshan’ in the Hydro-fluctuation Belt of the Three Gorges Reservoir Area

基于野外实地栽植试验,对重庆市万州区消落带历经1 a、3 a、6 a水淹后的中山杉在各水淹高程的保存率及树高、胸径、地径和冠幅进行研究。结果表明:(1)1次水淹后,166~175 m高程段内中山杉的保存率为100%;3次水淹后,168~175 m高程段保存率为100%;6次水淹后,170~175 m高程段保存率为98%。(2)中山杉的树高、胸径、地径和冠幅总体上随高程的降低而变小;但在一定高程范围内,水淹胁迫程度变强反而会促进中山杉树高的生长。(3)水淹初期,水淹对中山杉生长的影响显著;随着水淹次数增多,水淹对中山杉的影响不显著。(4)中山杉在地势低洼地带的保存率明显降低,但在根系裸露的条件下仍能正常生长。(5)中山杉能够改善土壤理化性质,有利于防止消落带水土流失。

The preserving rate,tree height,diameter at breast height（DBH）,ground diameter,and crown-width of the Taxodium hybrid ‘zhongshanshan＇at different elevations after one,three,and six periodic flooding periods were studied,based on located observations on the hydro-fluctuation belt in Wanzhou,Chongqing. Results showed that,after one flood period,the preserving rate of trees at the 166-175 m elevation was 100%;after three flood periods,the preserving rate at the 168-175 m elevation was 100%;after six flood periods,the preserving rate at the 170-175 m elevation was 98%. In general,the tree height,DBH,ground diameter,and crown-width decreased with the reduction of elevation,but on a certain elevation range,the tree height instead increased. At initial stage of flooding,the growth of trees was influenced by flooding;after several flood periods,the effects became insignificant. The preserving rate decreased significantly in water logged zone,but the trees were still in good condition when root exposed. The Taxodium hybrid ‘zhongshanshan＇could improve the physical and chemical properties of soil,and protect the hydro-fluctuation belt from water and soil erosion.