10年生珍贵树种人工林凋落物归还动态及持水能力研究

目的]研究10年生珍贵树种人工林凋落物归还动态及其持水能力。方法]对广西观光木、香梓楠、灰木莲红椎混交林、西南桦、火力楠及黑木相思6种10年生珍贵树种人工林凋落物归还动态进行了为期1 a的定位研究,并分析了凋落物的持水特性。结果]6种人工林凋落物归还均主要是叶子,观光木和黑木相思林归还动态呈双峰型季节变化;西南桦和香梓楠林为单峰型;灰木莲红椎混交林林为3峰型;火力楠则呈不规则型。其中最大峰值都出现在7月,1月份均出现最小值。6种林分凋落物持水率在30 min内迅速增大,0～8 h,林分凋落物持水率有较明显的增长趋势,之后逐渐趋于饱和。结论]观光木林、香梓楠林、灰木莲红椎混交林、西南桦林、火力楠及黑木相思林凋落物年归还量分别为7.17、7.78、10.42、6.04、7.59、6.78 t/(hm2.a)。6种不同人工林凋落物吸水速率为观光木>香梓楠>灰木莲红椎混交林>西南桦>火力楠>黑木相思。观光木、香梓楠、灰木莲红椎混交林、西南桦、火力楠及黑木相思林地凋落物最大持水率分别为470.10%、433.95%、405.86%、332.89%、304.50%及222.88%;最大持水量分别为2.53、1.92、2.21、0.77、1.23、0.46 mm。

The Returned Dynamics and Water Holding Characteristics of Litter of Ten Years Old Rare Tree Plantations

Objective]Study the returned dynamics and water holding characteristics of litter of ten years old rare tree plantations.Method]The dynamics and water holding characteristics of litters of six kinds of ten years old rare tree plantations as Tsoongiodendron odorum,Michelia hedyosperma,mixed forest of Magnoliaceae glanca and Castanopsis hystrix,Betula alnoides,Michelia macclurei and Acacia melanoxylon in Guangxi were studied.Result]The dynamics of littefall was mainly made of leaves,the monthly dynamics of total littefall of Tsoongiodendron odorum and Acacia melanoxylon showed the double-peak mode;Betula alnoides and Michelia hedyosperma showed the single-peak mode;Michelia macclurei and mixed forest of Magnoliaceae glanca and Castanopsis hystrix showed the three-peak mode.Maximum values were appearing in July,while minimum values were in January.The water holding capacity ratio of litter in 6 types of forest increased rapidly in 30 minutes.In 0-8 h,the water holding capacity ratio of litter had obvious rising tendency,after that,it reached saturation.Conclusion]The order of water absorption rate of litter in the six tree species was Tsoongiodendron odorum>Michelia hedyosperma>mixed forest of Magnoliaceae glanca and Castanopsis hystrix>Betula alnoides> Michelia macclurei >Acacia melanoxylon.Maximum water holding capacity ratio of those six tree plantations were 470.10%,433.95%,405.86%,332.89%,304.50% and 222.88%,respectively.The most proportional water holding capacity were 2.53,1.92,2.21,0.77,1.23,0.46 mm,respectively.