马尾松人工林林窗大小对两种凋落叶难降解物质含量的影响  

Effects of forest gap size on litter recalcitrant components of two tree species in Pinus massoniana plantations

作　　者：张艳[1] 张丹桔[1] 张健[1,2] 杨万勤[1] 邓长春[1] 李建平[1] 李勋[1] 唐仕姗 张明锦[1] 

机构地区：[1]四川农业大学林学院生态林业研究所,成都611130 [2]四川生态林业工程重点实验室,四川雅安625014

出　　处：《植物生态学报》2015年第8期785-796,共12页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31370628);国家科技支撑计划项目(2011BAC09B05);四川省科技支撑计划项目(12ZC0017);四川省科技厅应用基础项目(2012JY0047);四川省教育厅科技创新团队计划项目(11TD006)

摘　　要：林窗通过改变森林微环境及土壤环境而影响凋落物难降解物质的降解,目前关于人工林林窗对凋落物分解过程中难降解物质影响的研究较少。该文采用凋落物分解袋法,以马尾松(Pinus massoniana)人工林人工砍伐形成的7个不同面积的林窗(G1:100 m2、G2:225 m2、G3:400 m2、G4:625 m2、G5:900 m2、G6:1 225 m2、G7:1 600 m2)为研究对象,以林下为对照,研究了林窗大小对两种乡土树种——樟(Cinnamomum camphora)和红椿(Toona ciliata)凋落叶分解过程中难降解物质(木质素、纤维素、总酚、缩合单宁)含量的影响。结果表明:1)林窗大小对林窗中心红椿凋落叶缩合单宁、总酚、木质素的含量有显著影响,对其纤维素含量和樟凋落叶中4种难降解物质含量均无显著影响。随着林窗面积的增大,红椿凋落叶中除纤维素含量外的其余3种难降解物质含量,中小型林窗(G1–G5,G1:100 m2,G2:225 m2,G3:400 m2,G4:625 m2,G5:900 m2)低于大型林窗(G6、G7,G6:1 225 m2,G7:1 600 m2)。2)林窗不同位置,只有红椿凋落叶中缩合单宁含量林窗中心显著低于边缘,其余难降解物质含量和樟凋落叶中4种难降解物质含量均无显著差异。樟凋落叶的木质素含量在G3林窗显著低于林下;红椿凋落叶除纤维素含量外的其余难降解物质含量,中小型林窗从林窗中心到边缘均显著低于林下。3)随着分解时间的延长,两种凋落叶都表现出缩合单宁、纤维素含量降低,木质素含量升高,总酚含量先升高后降低的变化趋势。研究结果表明:中小型林窗(100–900 m2)较大面积林窗干扰更有利于凋落叶中难降解物质的降解,而林窗内的环境异质性应该是凋落物中难分解物质分解动态的主要调控因子,并且这种效应依赖于初始凋落物质量。Aims The objective of the study was to evaluate the dynamics of recalcitrant components during foliar litter decomposition at different forest gap size in Pinus massoniana plantation in the low hilly land, Sichuan basin.Methods The experiment was set up by thinning P. massoniana plantation to establish seven different gap sizes （G1： 100 m^2, G2： 225 m^2, G3： 400 m^2, G4： 625 m^2, G5： 900 m^2, G6： 1 225 m^2, G7： 1 600 m^2）. The contents of four recalcitrant components （condensed tannins, total phenol, lignin, cellulose） in foliar litter of two native species （Cinnamomum camphora and Toona ciliata） placed in litterbags at different locations in the forest gaps were evaluated. The litterbags placed under closed canopy were used as the control. Litterbags with air-dried leaves of C. camphora and T. ciliata were placed at center, edge of the gap and under the closed canopy in November 2013, and collected in December 2013, February 2014, May 2014 and August of 2014 for lab analysis.Important findings The results showed that： 1） Forest gap size had significant effect on the content of condensed tannins, total phenol and lignin for T. ciliata in gap center. However, the forest gap size had no significant effect on the content of recalcitrant components in the litters of C. camphora and cellulose content of T. ciliata. With the increase of gap size, except for cellulose content, the other three recalcitrant components content in small and medium sized gaps （G1–G5） were significant lower than in large gaps （G6, G7）. 2） The condensed tannis content of T. ciliata at the gap center were significant lower than at the gap edge. The lignin contents at gap center of G3 was significant reduced in the C. camphora litter. The condensed tannins, total phenol, and lignin contents of T. ciliata litter in small and medium gaps significantly decreased. 3） The contents of the four recalcitrant components in both species’ foliar litter changed with time. The contents of condensed tannins and ce

关 键 词：林窗面积 马尾松人工林 难降解物质 

分 类 号：S714[农业科学—林学]