林芳馨, 胥清利, 曲晓宇, 等. 光环境差异对杉木幼林林下植被多样性及根系种间竞争的影响[J]. 西南林业大学学报(自然科学), 2024, 44(5): 1–9. DOI: 10.11929/j.swfu.202310013
引用本文: 林芳馨, 胥清利, 曲晓宇, 等. 光环境差异对杉木幼林林下植被多样性及根系种间竞争的影响[J]. 西南林业大学学报(自然科学), 2024, 44(5): 1–9. DOI: 10.11929/j.swfu.202310013
Lin Fangxin, Xu Qingli, Qu Xiaoyu, Huang Ying, Chen Yu, Lin Kaimin, Cao Guangqiu. Effects of light environment differences on understory vegetation diversity and root interspecific competition of young Chinese fir (Cunninghamia lanceolata) artificial plantation[J]. Journal of Southwest Forestry University. DOI: 10.11929/j.swfu.202310013
Citation: Lin Fangxin, Xu Qingli, Qu Xiaoyu, Huang Ying, Chen Yu, Lin Kaimin, Cao Guangqiu. Effects of light environment differences on understory vegetation diversity and root interspecific competition of young Chinese fir (Cunninghamia lanceolata) artificial plantation[J]. Journal of Southwest Forestry University. DOI: 10.11929/j.swfu.202310013

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光环境差异对杉木幼林林下植被多样性及根系种间竞争的影响

Effects of light environment differences on understory vegetation diversity and root interspecific competition of young Chinese fir (Cunninghamia lanceolata) artificial plantation

  • 摘要: 为了解光环境变化与林下植被多样性、根系竞争的相关关系,以5年生不同造林密度(833、2500、6667株/hm2)杉木幼林为研究对象,测定分析林内光环境、林下植被多样性变化和根系竞争关系,探究造林密度引起的光环境差异对林下植被组成及根系竞争的影响。结果表明:造林密度增大显著影响林内光环境,833、2500、6667株/hm2密度冠下总辐射分别为77.82、31.94、14.03 μmol/(m2 ·s),林下总照度分别为5893.13、1130.7、761.5 Lx。草本层Shannon-Wiener指数、Pielou均匀度指数随密度增加呈先增后降的规律;灌木层Simpson优势度指数、Pielou 均匀度指数随造林密度的增大而下降。随密度的增大,杉木细根生物量与杉木根系竞争指数均逐渐增加,而林下植被生物量及其根系竞争指数逐渐下降。光环境相关指标与灌木层Pielou均匀度指数、草本层Simpson优势度指数呈显著正相关,与杉木根系竞争指数呈显著负相关,与林下植被根系竞争呈极显著正相关。因此,造林密度变化显著影响林内光环境,光环境相关指标随着造林密度增加而降低,造成杉木幼林林下植被生物量降低并影响林下植被多样性变化,并增强了杉木的根系竞争能力。综合杉木的生长状况,2500株/hm2为杉木适宜的造林密度更适合构建优质杉木人工林。

     

    Abstract:
    Objective Different afforestation densities can result in variations in the forest light environment. This study explores the relationship between changes in the light environment and the diversity and competition of understory vegetation.
    Methods The study focuses on 5-year-old Chinese fir saplings at three afforestation densities (833, 2500, 6667 trees/hm2), analyzing the forest light environment, changes in understory vegetation diversity, and root competition to examine the effects of afforestation density on understory vegetation composition and root competition.
    Results Increased afforestation density significantly affectedthe light environment within the forest (P<0.05), with total radiation under the canopy at densities of 833, 2500, and 6667 trees/hm2 being 77.82, 31.94, and 14.03 μmol/(m2·s), respectively, and total illuminance in the understory being 5893.13, 1130.7, and 761.5 Lux, respectively. The Shannon-Wiener index and Pielou's evenness index of the herb layer showed an initial increase followed by a decrease with increasing density; the Simpson's dominance index and Pielou's evenness index of the shrub layer decreased with increasing afforestation density. As density increased, the biomass of Chinese fir fine roots and the Chinese fir root competition index both gradually increased, while the biomass of understory vegetation and its root competition index gradually decreased. Light environment indicators were significantly positively correlated with the Pielou's evenness index of the shrub layer and the Simpson's dominance index of the herb layer (P<0.05), significantly negatively correlated with the Chinese fir root competition index (P<0.05), and showed a highly significant positive correlation with the root competition of understory vegetation (P<0.01).
    Conclusion Changes in afforestation density significantly affect the forest's light environment, with light-related indicators decreasing as afforestation density increases, leading to a reduction in the biomass of understory vegetation in Chinese fir saplings and affecting the diversity changes of understory vegetation, as well as enhancing the root competition ability of Chinese fir. Considering the growth condition of Chinese fir, an afforestation density of 2500 trees/hm2 is deemed more suitable for constructing high-quality Chinese fir plantations.

     

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