黔东南杉木纯林及其混交林凋落物年产量与月动态变化

摘要

采用空间替代时间和定位观测相结合的方法,在黔东南以杉木不同龄级纯林及中龄期混交林为研究对象,研究其凋落物年产量、月动态及影响因素,结果表明:(1)幼龄(≤10年)、近熟龄(21-25年)、成熟龄(26-35年)和过熟龄(≥36年)杉木纯林的凋落物产量为0.61t/(hm2·a)、3.38t/(hm2·a)、4.21t/(hm2·a)和5.75t/(hm2·a),中龄期柳杉-杉木林、马尾松-檫木-杉木林、毛竹-杉木林和马尾松-杉木林的凋落物产量为7.55t/(hm2·a)、4.23t/(hm2·a)、3.72t/(hm2·a)和3.25t/(hm2·a).(2)杉木纯林中幼龄林和近熟林、成熟林及过熟林的凋落物月产量差异显著,中龄期混交林中柳杉-杉木林和马尾松-杉木林的凋落物月产量差异也显著.杉木林凋落物月产量动态曲线呈3峰型,峰值出现在2-4月、7-10月和12月间.杉木不同龄级纯林及中龄期不同混交林类型内凋落物月产量动态曲线的X2检验值差异显著,季节性分布格局不同.(3)杉木纯林凋落物年产量和草本层植物生物量及土壤A层pH值的直线相关显著,混交林凋落物年产量和灌木层植物平均地径及高度、土壤A层及B层全磷含量的直线相关也显著.中龄期马尾松-檫木-杉木混交林及成熟龄期杉木纯林凋落物月产量和温度及降雨量相关显著,表明凋落物产量受气候-土壤-植被系统部分要素的综合影响.%By adopting the combination of space instead of time and location observation method,the annual values and monthly dynamics of litterfall and their influencing factors of pure forest with different age classes and different mixed-species forest types at middle age class of Cunninghamia lanceolata in southeastern Guizhou were studied.The results showed that:(1)Litterfalls of pure forest of Cunninghamia lanceolata in adolescent (≤10a),near mature (21-25a),mature (26-35a) and over mature age class (≥36a) was 0.61t/(hm2·a),3.38t/(hm2·a),4.21t/(hm2·a)and 5.75t/(hm2·a),respectively.Corresponding values of Crypotomeria fortunei-Cunninghamia lanceolata forest,Pinus massoniana-Sassafrsa tzumu-Cunninghamia lanceolata forest,Phyllostachys pubescens-Cunninghamia lanceolata forest and Pinus massoniana-Cunninghamia lanceolata forest at middle age class (11-20a)were 7.55t/(hm2·a),4.23t/(hm2·a),3.72t/(hm2·a) and 3.25t/(hm2·a),respectively.(2) Monthly average litterfall of adolescent age class had significantly difference with the corresponding values of near mature,mature and over mature age classes in pure forest,with significant difference between Pinus massoniana-Cunninghamia lanceolata forest and Crypotomeria fortunei-Cunninghamia lanceolata forest at middle age class.Monthly dynamics of litterfall was a 3-peak-model including 2-4,7-10 and 12 month at different peak values.X2 tests of monthly litterfall dynamics were significant difference in pure forest of different age classes or mixed forest types of middle age class with different distribution patterns in different seasons.(3)Annual production of pure forest litterfall were linear related significantly with herb plant biomass and soil pH value of A stratum,and the corresponding values of mixed-species forest were significantly linear correlation with diameter and height of shrub layer and total phosphorus content of soil A and B stratum.The monthly litterfall of Pinus massoniana-Sassafrsa tzumu-Cunninghamia lanceolata forest at middle age class and pure forest at mature age class were significantly associated with indicators of temperature and rainfall.It is indicated that litterfall affects synthetically by climate-soil-vegetation system.