Effects of thinning on leaf-fall and leaf-litter nitrogen concentration in hinoki cypress (Chamaecyparis obtusa Endlicher) plantation stands in Japan
Effects of thinning on leaf-fall and leaf-litter nitrogen concentration in hinoki cypress (Chamaecyparis obtusa Endlicher) plantation stands in Japan
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DOI：
10.1016/j.foreco.2007.12.007
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发表时间：
2008-04
影响因子：
3.7
通讯作者：
Y. Inagaki;S. Kuramoto;A. Torii;Yoshiki Shinomiya;H. Fukata
中科院分区：
文献类型：
--
作者：
Y. Inagaki;S. Kuramoto;A. Torii;Yoshiki Shinomiya;H. Fukata
在日本南部四国岛不同海拔(TNG和FMY)和不同立地条件下的两种常绿柏木(Chamaecyparis Obtusa Endlicher)人工林中，历时3年研究了间伐对鲜叶氮素浓度、凋落物氮素浓度和落叶物候的影响。选取两个相邻的400m×400m样地：其中一个样地在2002年进行了间伐，大约50%的树木被砍伐，另一个样地不砍伐树木作为对照。高海拔人工林(TNG)的土壤氮素矿化程度高于低海拔人工林(FMY)，鲜叶和凋落物氮浓度较高，落叶较早。两地间伐地表层土壤净氮素矿化量和鲜叶氮素浓度均显著高于对照地。凋落物氮浓度间伐小区略高于对照小区，且与年落叶50%的时间呈负相关。2004年强台风侵袭时，间伐样地落叶时间较早，凋落物氮素浓度较大。结果表明，落叶时间是影响凋落物氮素浓度的重要因素。结果表明，强台风对海拔较高的稀疏样地和人工林的影响较大。
The effects of thinning on fresh-leaf nitrogen concentration, leaf-litter nitrogen concentration, and leaf-fall phenology were evaluated over 3 years in two evergreen hinoki cypress (Chamaecyparis obtusa Endlicher) plantations at different elevations (TNG and FMY) and with different site characteristics on Shikoku Island in southern Japan. Two adjacent study plots (400m×400m) were selected:in one plot thinning was conducted in 2002 where about 50% of trees were removed and in the other plot no trees were cut as the control. The plantation at a higher elevation (TNG) was characterized by higher soil nitrogen mineralization, higher fresh-leaf and leaf-litter nitrogen concentration and earlier leaf-fall than that at a lower elevation (FMY). The net nitrogen mineralization in the surface soil and fresh-leaf nitrogen concentration in the thinned plots was significantly greater than in the control plots across both sites. Leaf-litter nitrogen concentration was marginally higher in the thinned plots than in the control plots and was negatively correlated with the time of 50% annual leaf-fall. When severe typhoons affected the area in 2004, leaf-fall became earlier and the leaf-litter nitrogen concentration was greater in the thinned plots. The results suggest that the time of leaf-fall is an important factor affecting leaf-litter nitrogen concentration. The results imply that the effects of severe typhoons are greater in the thinned plots and plantations at a higher elevation.