湖南会同不同林分类型杉木人工林凋落物水文效应

Hydrological Effects of Litters in Different Types of Cunninghamia lanceolata Plantations in Huitong of Hunan,China

[目的]以我国亚热带不同林分类型杉木人工林为研究对象,分析比较其凋落物层生态水文效应的差异,为杉木人工林林下生态管理和生态系统服务评估提供科学依据。[方法]采用野外调查和室内浸提试验相结合的方法,对湖南会同3种不同类型杉木人工林(杉木纯林、杉木-樟树混交林、杉木-桤木混交林)的各分解层凋落物储量、吸持水特性以及有效拦蓄能力进行测定分析。[结果](1)不同林分类型杉木人工林凋落物现存量在7.94~8.88 t·hm^(-2),杉木-桤木混交林>杉木-樟树混交林>杉木纯林,半分解层现存量占总现存量的比例高于未分解层;(2)杉木人工林凋落物在浸水0~4 h内吸水速率增加较快,4~10 h内持水量增加速率减缓,并逐渐趋于饱和;最大持水率和最大持水量表现为半分解层大于未分解层,针阔混交林各分解层凋落物最大持水率和最大持水量高于杉木纯林;(3)3种类型杉木人工林最大拦蓄率变化范围为152.33%~229.55%,最大拦蓄量和有效拦蓄量分别在12.62~17.94 t·hm^(-2)和10.26~14.75 t·hm^(-2),且均为杉木-樟树混交林和杉木-桤木混交林显著高于杉木纯林(P<0.05)。[结论]湖南会同不同林分类型杉木人工林的水文效应存在一定差异,杉木-樟树混交林和杉木-桤木混交林的水文功能优于杉木纯林,建议今后该地区杉木人工林经营管理和植被恢复中优先考虑杉木与阔叶树种混交的模式。

[Objective]To evaluate the impact of litter on hydrology in different types of Cunninghamia lanceolata plantations,and provide references for the management of understory and the assessment of ecosystem services.[Method]Based on field investigation and immersion experiments,the authors examined the storage capacity,water retention characteristics,and effective interception capacity of the litters collected from pure Cunninghamia lanceolata forest(PC),mixed forest of Cunninghamia lanceolata and Cinnamomum camphora(MCC)and mixed forest of Cunninghamia lanceolata and Alnus cremastogyne(MCA)in subtropical China.[Result](1)The litter storage of different types of Cunninghamia lanceolata plantation varied from 7.94 to 8.88 t·hm^(-2),with an order of MCC>MCA>PC,and the proportion of semi-decomposed litters was greater than that of undecomposed litters.(2)The water-absorption rate of litter in various plantations increased rapidly within the initial 4 hours of immersion,followed by a slower increase at 4-10 hours of immersion,and finally saturated.Compared with semi-decomposed litter,the undecomposed litter had a higher maximum water-holding capacity and maximum water-holding capacity.Both semi-decomposed and undecomposed litters in mixed plantations exhibited higher maximum water-holding rate and maximum water holding capacity than that in pure Cunninghamia lanceolata plantation.(3)The maximum interception rate of the three types of plantation ranged from 152.33%to 229.55%.The maximum and effective interception capacity were 12.62-17.94 t·hm^(-2) and 10.26-14.75 t·hm^(-2),respectively,exhibiting higher in both MCC and MCA than in PC(P<0.05).[Conclusion]The hydrological effect of litters varies among different types of Cunninghamia lanceolata plantation in Huitong,while the hydrological characteristics of mixed forests of Cunninghamia lanceolata with broad-leaved species are significantly better than that of pure Cunninghamia lanceolata plantation.Therefore,mixed stand of Cunninghamia lanceolata with broad-leaved species should be recommended in forest management and vegetation restoration.