Zhang Yan, Zhang Dan Ju, Li Xun, Liu Hua, Zhang Ming Jin, Yang Wan Qin, Zhang Jian
Institute of Ecology & Forestry, College of Forestry, Sichuan Agricultural University, Chengdu 611130, China.
Sichuan Province Key Laboratory of Forestry Ecological Engineering, Chengdu 611130, China.
Ying Yong Sheng Tai Xue Bao. 2016 Apr 22;27(4):1116-1124. doi: 10.13287/j.1001-9332.201604.025.
The objective of the study was to evaluate the dynamics of recalcitrant components during foliar litter decomposition under edge effects of forest gap in Pinus massoniana plantations in the low hilly land, Sichuan basin. A field litterbag experiment was conducted in seven forest gaps with different sizes (100, 225, 400, 625, 900, 1225, 1600 m) which were generated by thinning P. massoniana plantations. The degradation rate of four recalcitrant components, i.e., condensed tannins, total phenol, lignin and cellulose in foliar litter of two native species (Cinnamomum camphora and Toona ciliata) at the gap edge and under the closed canopy were measured. The results showed that the degradation rate of recalcitrant components in T. ciliata litter except for cellulose at the gap edge were significantly higher than that under the closed canopy. For C. camphora litter, only the degradation of lignin at the gap edge was higher than that under the closed canopy. After one-year decomposition, four recalcitrant components in two types of foliar litter exhibited an increment of degradation rate, and the degradation rate of condensed tannin was the fastest, followed by total phenol and cellulose, but the lignin degradation rate was the slowest. With the increase of gap size, except for cellulose, the degradation rate ofthe other three recalcitrant components of the T. ciliata at the edge of medium sized gaps (400 and 625 m) were significantly higher than at the edge of other gaps. However, lignin in the C. camphora litter at the 625 m gap edge showed the greatest degradation rate. Both temperature and litter initial content were significantly correlated with litter recalcitrant component degradation. Our results suggested that medium sized gaps (400-625 m) had a more significant edge effect on the degradation of litter recalcitrant components in the two native species in P. massoniana plantations, however, the effect also depended on species.
本研究的目的是评估四川盆地低山丘陵区马尾松人工林林窗边缘效应下，凋落物分解过程中难降解组分的动态变化。通过对马尾松人工林进行间伐，形成了七个不同大小（100、225、400、625、900、1225、1600平方米）的林窗，开展了野外凋落物袋试验。测定了两种本地物种（樟树和香椿）林窗边缘和郁闭林下凋落物中四种难降解组分，即缩合单宁、总酚、木质素和纤维素的降解率。结果表明，除纤维素外，香椿凋落物在林窗边缘的难降解组分降解率显著高于郁闭林下。对于樟树叶凋落物，只有林窗边缘的木质素降解率高于郁闭林下。经过一年的分解，两种凋落物中的四种难降解组分的降解率均有所增加，缩合单宁的降解率最快，其次是总酚和纤维素，而木质素的降解率最慢。随着林窗面积的增加，除纤维素外，香椿在中等大小林窗（400和625平方米）边缘的其他三种难降解组分的降解率显著高于其他林窗边缘。然而，樟树叶凋落物在625平方米林窗边缘的木质素降解率最高。温度和凋落物初始含量均与凋落物难降解组分的降解显著相关。我们的研究结果表明，中等大小的林窗（400-625平方米）对马尾松人工林中两种本地物种凋落物难降解组分的降解具有更显著的边缘效应，然而，这种效应也取决于物种。
