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结构化经营对栎松混交林林分空间结构及稳定性的影响 被引量:25
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作者 万盼 刘文桢 +3 位作者 刘瑞红 王鹏 王宏翔 惠刚盈 《林业科学》 EI CAS CSCD 北大核心 2020年第4期35-45,共11页
【目的】研究结构化经营对栎松混交林林分空间结构一元、二元分布特征及稳定性的影响,为结构化经营技术在栎松混交林中的实施和评价提供科学依据。【方法】以甘肃小陇山自然保护区百花林场大干子沟天然栎松混交林为研究对象,2012年设置1... 【目的】研究结构化经营对栎松混交林林分空间结构一元、二元分布特征及稳定性的影响,为结构化经营技术在栎松混交林中的实施和评价提供科学依据。【方法】以甘肃小陇山自然保护区百花林场大干子沟天然栎松混交林为研究对象,2012年设置1块50 m×50 m、2块30 m×30 m固定样地,实施结构化经营;同时设置3块20 m×20 m固定样地,不实施经营措施,作为对照;2017年对所有样地进行复测。采用角尺度、大小比数和混交度对比经营样地和未经营样地林分空间结构5年前后的变化,并通过最优林分状态的π值法则评价林分稳定性。【结果】1)经营样地在经营前林分水平分布格局接近团状分布,实施结构化经营5年后林分水平分布格局为随机分布;未经营样地林分水平分布格局始终为团状分布。实施结构化经营5年后林分混交度较经营前增加10.4%,未经营样地5年后林分混交度较5年前仅增加5.5%。2)实施结构化经营5年后的林分中,处于高度混交且为随机分布、高度混交且为中庸到优势的林木(优势微结构)比例较经营前分别增加21.63%和13.84%;未经营样地5年后的林分中,处于高度混交且为随机分布、高度混交且为中庸到优势的林木(优势微结构)比例较5年前仅分别增加3.75%和3.35%。实施结构化经营5年后的林分中,处于中庸到优势且为随机分布的林木比例较经营前降低6.79%;未经营样地5年后的林分中,处于中庸到优势木且为随机分布的林木比例较5年前降低8.10%。3)林分状态单位圆分析表明,林分状态评价值在实施结构化经营5年后较经营前提高27.09%,状态由较差到良好,林分稳定性增强;未经营样地林分状态评价值在自然生长5年中提高13.24%,状态仍为较差。【结论】结构化经营可使林分水平分布格局合理、混交度大幅度增加,优势微结构(高度混交且为随机分布、高度混交且为中庸到优势)林木比例得到明显提高,林分稳定性增强。 展开更多
关键词 空间结构 π值法则 林分稳定性 栎松混交林 小陇山
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Effects of Environmental Factors on Tree Seedling Regeneration in a Pine-oak Mixed Forest in the Qinling Mountains, China 被引量:14
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作者 YU Fei WANG De-xiang +3 位作者 SHI Xiao-xiao YI Xian-feng HUANG Qing-ping HU You-ning 《Journal of Mountain Science》 SCIE CSCD 2013年第5期845-853,共9页
Natural seedling regeneration and tree establishment are affected by various environmental factors. In this study, we established eight, eight, six, and four independent forest stands (each stand was further divided ... Natural seedling regeneration and tree establishment are affected by various environmental factors. In this study, we established eight, eight, six, and four independent forest stands (each stand was further divided into five subplots) respectively based on the altitudinal gradient, stand density, slope location, and slope aspect to investigate the effects of environmental factors on tree seedling regeneration in a pine-oak mixed forest. The results indicated that the seedling density was significantly higher at altitudes of 1,283 m to 1,665 m, whereas the sapling density did not differ with altitudes. The seedling and sapling density decreased significantly at 1,835 m. The seedling densities on the upper slopes were much higher than those on the middle and lower slopes, whereas the sapling density had no difference. The sapling density decreased southwest (20°-75°) whereas gradually from the it increased on the shady slopes to the northeast (40°). The seedling density increased from southwest (20°) to northeast (40°The seedling and sapling densities increased with the stand density (850 trees ha-1 to 1,525 trees ha-1) whereas the sapling density was significantly lower in stands (1,9oo trees ha-O. Principal components analysis showed that the slope aspect and stand density had more important roles in tree regeneration in this study region compared with the other two factors. Therefore, our findings suggest that it will be beneficial to keep stands at a moderate density on shady slopes. Appropriate thinning of higher density stands is also expected to promote the natural regeneration of pine-oak mixed forest. 展开更多
关键词 Environmental factors Pine-oak mixedforest Qinling Mountains REGENERATION
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