林分因子对成都绕城高速路域不同人工林群落物种多样性的影响

【目的】为探究林分因子对不同路域人工林群落物种多样性的影响，为成都路域人工林营造与管理提供参考。【方法】研究采用典型样地法对成都绕城高速路域现种植的5种不同人工林群落（Ⅰ，加杨纯林；Ⅱ，樟树、加杨混交林；Ⅲ，樟树纯林；Ⅳ，樟树、巨桉混交林；Ⅴ，巨桉纯林）进行全面踏查，调查林分因子及林下植被物种多样性。【结果】（1）研究区共记录植物184种，隶属于72科132属。5种不同人工林群落乔-灌-草三层的植物科属种数量均为草本层＞灌木层＞乔木层，其中樟树纯林记录到的林下物种数最多。（2）构树（Broussonetia papyrifera）和葎草（Humulus scandens）重要值占比大，分别占据不同人工林群落灌木层与草本层的优势地位。（3）在5种不同人工林群落中，樟树纯林的灌木物种丰富度指数D显著高于其他群落（P<0.05）；草本层的Shannon-Wiener指数H、Simpson指数H′和D大小变化趋势一致，表现为群落Ⅲ>Ⅳ>I>I>V，其中樟树纯林的H显著高于樟树、巨桉混交林外其他群落（P<0.05）。（4）冗余分析结果表明：乔木层平均冠幅与灌木层的D和H、草本层的H、H''、D、Jsw均呈显著正相关（P<0.01），与灌木层的H''和Jsw均呈显著负相关（P<0.01）；乔木层平均枝下高与灌木层的H、H''、D、Jsw均呈显著正相关（P<0.01）。【结论】乔木层的树种组成、平均枝下高和平均冠幅显著影响路域人工林群落的物种多样性，选择合适树种并定期修枝管理，将有利于路域人工林良好乔灌草群落结构形成和林下植被物种多样性维持。 关键词 林分因子；路域人工林；林下植被；物种多样性

Effect of Forest Factor on Species Diversity of Different Plantation Communities in Chengdu Ring Expressway

[Objective] In order to explore the effects of stand factors on the species diversity of plantation communities in different road areas, and to provide a reference for the construction and management of plantations in Chengdu road area. [Methods] This study used the typical plot method to analyze five different plantation communities (I, poplar pure forest; Ⅱ, camphor and poplar mixed forest; Ⅲ, pure camphor forest; Ⅳ, mixed forest of camphor and eucalyptus; V, eucalyptus grandis forest) to investigate the stand factors and species diversity of understory vegetation. [Results] (1) A total of 184 plant species belonging to 72 families and 132 genera were recorded in the study area. The number of plant species in the tree-shrub-grass layer of five different plantation forest communities varied from herb layer > shrub layer > tree layer, among which the number of understory species recorded in the pure camphor forest; was the highest. (2) The importance values of Broussonetia papyrifera and Humulus scandens dominated the shrub layer and herb layer of different plantation forest communities, respectively. (3) Among the five different plantation forest communities, the shrub species richness index D of pure camphor forest was significantly higher than that of the other communities(P<0.05); the Shannon-Wiener index H, Simpson index H′ and D size of the herbaceous layer had the same trend of change, which showed that the community: Ⅲ>Ⅳ>I>I>I>V, of which H of pure camphor forest was significantly higher than that of the other communities except mixed forest of camphor and eucalyptus(P<0.05). (4) The results of redundancy analysis showed that the average crown width in the tree layer was significantly positively correlated with D and H in shrub layer, H, H'', D and Jsw in herbaceous layer (P<0.01), and negatively correlated with H'' and Jsw in shrub layer (P<0.01). The average height under branches in the tree layer was significantly positively correlated with H, H'', D, and Jsw in shrub layer (P<0.01). [Conclusion] The study concluded that tree species composition, average undershoot height and average crown width of the tree layer significantly affected the species diversity of plantation communities in the road area, and the selection of appropriate tree species and regular pruning management would be conducive to the formation of good tree and shrub community structure and the maintenance of understory vegetation species diversity in road plantations.