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在小陇山麻沿林场选择有代表性的中幼龄油松(Pinus tabulaeformis)人工林,设置1 000m×30m样带,在样带内随机布置了12个20 m×20 m标准地,按株数设计3种(15%、25%、35%)间伐强度,0.0%为对照,3次重复;运用SVMS软件分析不同间伐强度对林分结构特征和活力的影响。结果显示:经过3种强度间伐后,油松在树种组成中的比例下降,一些阔叶更新树种在树种组成中的比例随间伐强度的增加呈增大趋势,25%强度间伐后林分中漆树分布株数是对照的2.5倍,35%强度间伐后林分中锐齿栎分布株数是对照的3.5倍;除15%间伐强度平均林层数高于对照外,25%和35%间伐强度平均林层数低于对照,间伐后上层分布树种随间伐强度的增大而增多;15%强度间伐后林分水平分布格局没有发生变化,25%和35%强度间伐后林分水平分布从随机分布转变为聚集分布状态;3种间伐强度间伐后林分平均混交度分别比对照增加了2.68%、31.86%和58.10%,表示林木个体竞争大小的大小比数分别为0.497 8、0.4914、0.490 0,比对照(0.498 5)减小了,表示林木生长空间大小的开敞度分别是0.323 0、0.327 0、0.367 0,高于对照(0.2730);随间伐强度的增加林分混交度增加,从零度混交变为弱度混交,林木个体间竞争减弱,林木生长空间扩大,从不足到基本充足。间伐1a后天然更新幼苗数量分别是对照的6.0、12.5、13.1倍,间伐增加了天然更新能力,增强了林分活力。3种间伐强度中,15%间伐强度对林分结构和树种组成影响较小。研究结果证明,小陇山林区中幼龄期的油松人工林宜采用25%到35%间伐强度能有效改善林分结构、调整树种组成,增加林分活力;通过多次合理间伐强度措施的实施能有效促进林分向复层、异龄、混交林演替,为油松中幼龄人工林结构化经营提供参考。
A typical young and middle-aged Pinus tabulaeformis plantation was selected in the small-hillside Ma’anshan farmland of Xiaolongshan Mountain to set up a 1000m × 30m transect. 12 standard plots of 20m × 20m were randomly arranged in the transect Three kinds (15%, 25%, 35%) of thinning intensity were designed for plant number, and 0.0% were used as control and repeated for three times. The effects of different thinning intensities on the characteristics and vigor of stand were analyzed by SVMS software. The results showed that the percentage of Pinus tabulaeformis in the species composition decreased after thinning with three intensities. The proportion of some broad-leafed species in tree species increased with the increase of the thinning intensity. After 25% The number of distributions was 2.5 times as much as that of the control. The number of distribution of sharp teeth of Quercus acutissima in the 35% strength thinning forest was 3.5 times that of the control. The mean thinning intensity of 25% and 35% The number of stratum was lower than that of the control. After the thinning, the upper distribution tree species increased with the increase of the thinning intensity. The distribution pattern of the stand at 15% strength did not change after the thinning. The distribution of the stand at 25% and 35% The average mixed degree of the three kinds of thinning intensities after cutting was increased by 2.68%, 31.86% and 58.10% respectively compared with the control, indicating that the ratio of the size of individual competition of forest trees was 0.497 8,0.4914,0.490 0, respectively The control (0.498 5) decreased, indicating that the open space of forest growth space was 0.323 0,0.327 0,0.367 0, higher than the control (0.2730). With the increase of thinning intensity, Become weak mix, a forest Competition among weakened trees growing space expanded from the basic to the lack of adequate. The number of natural regeneration seedlings after thinning was 6.0, 12.5 and 13.1 times of the control, respectively. Thinning increased natural regeneration ability and increased the vigor of stand. Among the three kinds of thinning intensities, 15% thinning intensity had little effect on the stand structure and tree species composition. The results showed that it is appropriate to use the thinning intensity of 25% to 35% to improve the stand structure, adjust the tree species composition and increase the stand vigor of Pinus tabulaeformis plantation in Xiaolongshan forest area. By means of multiple thinning intensity measures The implementation can effectively promote the succession of stand to stratification, heterogeneity and mixed forest, and provide a reference for the management of young plantation in the pine tree.