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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。
Gap affects the degradation of degraded litter by altering the forest microenvironment and soil environment. At present, there are few researches on the effect of plantation gap on the refractory degradation during litter decomposition. In this paper, we use litter decomposition bag method and seven different areas of Gap (G1: 100 m2, G2: 225 m2, G3: 400 m2, G4: 625 m2) formed by artificially cutting Pinus massoniana plantation, G5: 900 m2, G6: 1 225 m2, G7: 1 600 m2) were studied in this study. The effects of gap size on two native tree species, Cinnamomum camphora and Toona ciliata ) Litter decomposition process of refractory substances (lignin, cellulose, total phenols, condensed tannins) content. The results showed as follows: 1) The size of forest window had a significant effect on the content of condensed tannin, total phenols and lignin in the litter of Toona caryophylla, but no significant difference in the content of cellulose and the content of the four refractory substances influences. With the increase of the gill area, the contents of three other refractory substances besides the cellulose content in the litter of Toona ciliata var. Tibetanus, the small and medium sized gaps (G1-G5, G1: 100 m2, G2: 225 m2, G3: 400 m2, G4: 625 m2, G5: 900 m2) is lower than that of a large gap window (G6, G7, G6: 1 225 m2, G7: 1 600 m2). 2) In the different positions of the gap, only the center of condensation gap tannin content in the litter of Red Toona sinensis was significantly lower than the edge, and the content of other refractory substances and the contents of the four refractory substances in the leaves were not significantly different. The content of lignin in the deciduous leaves was significantly lower than that in the G3 gill; the contents of other refractory substances except the cellulose content in the litter of the red cedar were smaller than those in the understorey. 3) With the prolongation of decomposition time, both litter leaf litter showed condensed tannin, decreased cellulose content, lignin content, total phenolic content increased first and then decreased. The results showed that the interference of large-area gap with small-sized forest window (100-900 m2) was more conducive to the degradation of refractory matter in litter, and the environmental heterogeneity in littoral should be the decomposition of refractory matter in litter The main dynamic regulator, and this effect depends on the initial litter quality.