%0 Journal Article %T 近自然化改造对桂南马尾松和杉木人工林结构特征的影响 %A 刘志龙 %A 明安刚 %A 贾宏炎 %A 蔡道雄 %A 马 %A 跃 %A 王亚南 %A 孙冬婧 %J 南京林业大学学报(自然科学版) %D 2017 %R 10.3969/j.issn.1000-2006.201606040 %X 【目的】为提升人工林质量及培育珍贵树种大径材,研究近自然化改造对林分结构变化的影响,通过近自然化改造改变林分组成和结构,进而调整林木生长和林分稳定性。【方法】以广西凭祥地区1993年造林并于2008年开始近自然化改造的马尾松和杉木人工林为研究对象,运用混交度、大小比数和角尺度参数分析近自然化改造后林分结构特征的变化。【结果】①对照林分的直径结构遵从正态分布,近自然化改造林分表现出向倒“J”形过渡的特征,对照林分的树高结构呈单峰型,而近自然化改造林分则呈双峰型; ②近自然化改造明显提高了林分混交度,马尾松和杉木对照林分的平均混交度由0.00和0.16分别提高到自然化改造林分的0.82和0.89; ③近自然化改造对林分角尺度影响较小,杉木林从均匀分布状态向团状分布转变,但马尾松林一直处于随机分布状态; ④近自然化改造增加了优势和亚优势的个体比例,对照林分总体处于中庸生长状态,马尾松和杉木近自然化改造林分的平均大小比数分别为0.40和0.46。【结论】从林分非空间结构角度看,近自然化改造林分提高了林分树种组成,径级结构向异龄林直径分布倒“J”形的特征过渡; 从林分空间结构角度看,近自然化改造林分逐步摆脱了人工纯林零度或弱度混交、水平分布均匀和中庸状态的结构特征。研究区补植树种和天然更新树种已成功地在林分中更新和生长,促进了林分混交度、树种多样性的提高和林分空间结构的优化,林分向异龄复层混交林方向发展。</br>【Objective】The close-to-nature transformation changes the forest composition and stand structure and thus, affects the tree growth and stand stability. Therefore, a study on the effects of close-to-nature transformation on stand structure has important significance in improving the quality of degrading plantations and producing large-diameter timber. 【Method】This study focused on Pinus massoniana and Cunninghamia lanceolata plantations, afforested in 1993 and close-to-nature transformated in 2008. Three parameters(mingling, uniform angle index, and neighborhood comparison)were considered to compare the changes in stand spatial structure before and after close-to-nature transformation. 【Results】① The diameter of control stands followed normal distribution, while the close-to-nature transformation stands showed the reversal “J” type. The tree height of control stands was a single peak type, whereas that of close-to-nature transformation plantations showed a double peak. ② The close-to-nature transformation improved stand mingling significantly, the average mingling increased from 0.00 and 0.16 to 0.82 and 0.89 in the P. massoniana and C. lanceolata control stands and their close-to-nature stands respectively. ③ Close-to-nature transformation has little effect on the uniform angle index, it changed from uniform distribution to reunion distribution in C. lanceolata stands; however, it has been in a random distribution state in P. massoniana stands. ④ The number of dominant and sub-dominant individuals were increased after close-to-nature transformation. The average neighborhood comparison of P. massoniana and C. lanceolata close-to-nature stands was 0.40 and 0.46 respectively, whereas there were generally medium individuals in the control stands. 【Conclusion】 In the perspective of non-spatial structure, close-to-nature transformation improves the composition of forest species, and the diameter of trees is transferred to an inverted “J” type as uneven %K 人工林 %K 近自然化改造 %K 林分结构 %K 角尺度 %K 混交度 %K 大小比数< %K /br> %K plantation %K close-to-nature transformation %K stand structure %K uniform angel index %K mingling %K neighborhood comparison %U http://nldxb.njfu.edu.cn/oa/darticle.aspx?type=view&id=201704016