Differences in the Decomposition Degree of the Content of Refractory Substances in Different Structural Components of Fallen Wood in Tsuga longibracteata Forest
[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.
Tsuga longibracteata forestfallen woodrefractory substancesstructural componentsstand type
万方数据
维普
