闽北不同类型毛竹林水量平衡

The water-balance of different forest types of Phyllostachys edulis in north of Fujian province

以闽北杉木林和常绿阔叶林为对照,对闽北山区主要毛竹林类型即竹杉混交林、毛竹纯林和竹阔混交林的水量平衡进行了研究。结果表明:林分水量主要收入项为降水,支出项为蒸散量、土壤蓄水变化量和径流量。其中,蒸散量是各林分水量输出的最大项,年蒸散量占年降水量的97.69%～99.12%,地表径流量为支出水量最小项,占降水量的0.52%～1.11%。闽北毛竹林全年输入水量大于输出水量,能够维持水量平衡,但存在季节性缺水问题。其中,2—3月和8—10月蒸散量大于降水量,应对毛竹林进行适当的补水。群落结构对水量平衡有重要的影响。降水量不同,群落不同层次的生物量与水分输出量的相关性不同,降水量较低时,地表径流、土壤蓄水变化量和蒸散量与乔木层或者草本层生物量的相关性较强;物种数与林分的蒸散系数及土壤调蓄水分的能力变化密切相关,物种总数和灌木物种数大,其蒸散系数大,蓄水变化量小。3种类型林分中,竹阔混交林物种数量较大,土壤水分补充迅速,且有较大的生产力,是一种较好的经营模式。

The water-balance of typical Phyllostachys edulis forests（Ph.edulis and Cunninghamia lanceolata mixed forest,Ph.edulis pure forest and Ph.edulis and broad-leaved tree mixed forest） were studied in comparison with C.lanceolata forest and evergreen broadleaved forest in the North of Fujian province.The result showed that main income of the stand water was precipitation and the expenditure was evapotranspiration,system moisture change and the amount of runoff.The evaporation was the maximum item of water output,accounting for 97.69% to 99.12% of the precipitation and the runoff was minimum item,accounting for 0.52% to 1.11% of precipitation.The moso bamboo forest was in the status of water-balance because their actual expenditure of all forest stands was less than the actual input water.However,there was seasonal water shortage for those forest types.The evapotranspiration exceeded the amount of rainfall in Febr to Mar and Aug to Oct.It was important to replenished water for the growth of bamboo forest.The community structure had important effect on water balance.The correlation coefficient between the biomass and the expenditure was different in different months.The correlation between the biomass and the expenditure was stronger when the rainfall was less.There was a close relationship between the species numbers and the expenditure items.The evapotranspiration coefficient was higher and the water variation ratio was lower when the number of species was more.Ph.edulis and broad-leaved tree mixed forest was a good business model because it could maintain species diversity,replenishment the soil moisture quickly and had greater productivity.