摘要
[目的]探究倒木不同结构组分难降解物含量的分解程度差异,为长苞铁杉林科学经营提供理论依据.[方法]以福建省天宝岩国家级自然保护区中的长苞铁杉林倒木为对象,采用空间代替时间法,在4种林分类型(长苞铁杉纯林、长苞铁杉+阔叶树混交林、长苞铁杉+猴头杜鹃混交林、长苞铁杉+毛竹混交林)中,探究倒木不同结构组分(树皮、边材、心材)的难降解物含量在分解过程中的变化趋势.[结果]显示:(1)在倒木分解过程中,纤维素、总酚和缩合单宁含量降低,木质素含量升高;倒木缩合单宁含量除了在长苞铁杉+阔叶树混交林中随腐烂等级增加呈先升后降趋势外,在其它 3种林分类型中均呈现逐渐下降趋势;(2)从第Ⅰ腐烂等级到第Ⅴ腐烂等级,长苞铁杉倒木的难降解物质含量变化均为显著,其中树皮、边材和心材的纤维素含量分别下降100.08 g·kg-1(20.6%)、73.79 g·kg-1(15.0%)和89.87 g·kg-1(17.5%);木质素含量分别升高42.53 g·kg-1(37.7%)、36.71 g·kg-1(37.9%)和22.25 g·kg-1(22.0%);缩合单宁含量分别下降 34.45 g·kg-1(47.4%)、11.02 g·kg-1(23.5%)和 16.83 g·kg-1(44.0%);总酚含量分别下降 4.87 g·kg-1(57.6%)、1.78 g·kg-1(32.0%)和 2.06 g·kg-1(41.7%).[结论]长苞铁杉林倒木分解中难降解物含量除了与其自身C、N、P含量有关外,还受到林分类型及其结构组分与林分类型交互作用的综合影响.研究结果为指导长苞铁杉林分经营提供了理论依据.
Abstract
[Objective]This study aimed to investigate the variation in the decomposition degree of refract-ory substances in different structural components of fallen wood and provide a theoretical basis for the sci-entific management of Tsuga longibracteata forests.[Method]Based on the fallen wood from Tsuga lon-gibracteata forests within the Tianbaoyan National Nature Reserve of Fujian Province,the space-for-time substitution method was employed to examine changes in the content of refractory substances within dif-ferent structural components(bark,sapwood,and heartwood)of fallen wood across four forest types(T.longibracteata pure forest,T.longibracteata+broad-leaved mixed forest,T.longibracteata+R.simiarum mixed forest,T.longibracteata+P.pubescens mixed forest)during the decomposition process.TChanges in the content of refractory substances within different structural components(bark,sapwood,and heart-wood)of fallen wood were investigated throughout the decomposition process.[Results]Results showed that:(1)During the decomposition process of fallen logs,the contents of cellulose,total phenols,and con-densed tannins decreased,while the content of lignin increased.The condensed tannin content of fallen wood exhibited a gradual downward trend in the other three forest types except for the T.longibracteata+broad-leaved mixed forest,which showed an initial increase followed by a decrease with the increase of decay level.(2)There was a significant change in the content of recalcitrant substances in the fallen wood of Tsuga longibracteata.with a decrease of 100.08 g·kg-1(20.6%),73.79 g·kg-1(15.0%)and 89.87 g·kg-1(17.5%)in the cellulose content of bark,sapwood and heartwood,respectively.The lignin content in-creased by 42.53 g·kg-1(37.7%),36.71 g·kg-1(37.9%)and 22.25 g·kg-1(22.0%),respectively.The con-densed tannin content decreased by 34.45 g·kg-1(47.4%),11.02 g·kg-1(23.5%)and 16.83 g·kg-1(44.0%),respectively.The total phenolic content decreased by 4.87 g·kg-1(57.6%),1.78 g·kg-1(32.0%)and 2.06 g·kg-1(41.7%),respectively.[Conclusion]In addition to its own C,N,P content,the content of refractory substances in the decomposition of fallen wood of T.longibracteata forest is also affected by the interac-tion of stand type and its structural components with stand type.The results provide a theoretical basis for guiding the management of Tsuga longibracteata forest.
维普
万方数据