正宁县油松人工林发育过程中林下群落结构和物种多样性的研究

以正宁县中湾林场油松人工林为研究对象，用空间代替时间的方法，从Raunkiaer生活型和多样性指数等方面对林下群落结构及物种多样性进行了研究。结果表明:1）不同发育阶段油松人工林和对照样地植物种类组成丰富，共包含29个科61个属80种；从油松幼龄林开始，林下物种逐渐丰富，耐阴植物和广生态幅的植物逐渐取代阳性植物并表现出优势地位；2）油松人工林林下高位芽、地上芽和地面芽植物占主要优势；灌木层均以高位芽层片为优势层片，地面芽和地上芽层片为草本层的优势层片；3）随着油松人工林发育，林下总体物种多样性和均匀度指数增加，近熟林林下植物丰富度显著高于中龄林，均匀度指数显著高于幼龄林。说明油松人工林的种植很大程度改变了群落的面貌，不仅改善了林下群落结构，而且具有显著恢复生物多样性的功能。

Understory Community Structure and Species Diversity of the Chinese Pine Plantations at Different Developmental Stages in Zhengning County

Taking the Pinus tabulaeformis plantations at different developmental stages in Zhongwan Forest Farm, Zhengning County as the objects, the concept of substituting spatial sequence for time successional sequence was adopted to investigate the understory community structure and species diversity from the aspects of Raunkiaer life-form, diversity index, etc. The following results were obtained: 1) 80 plant species were observed in the understory, belonging to 29 families and 61 generas; starting from the young stands, the plant species unevenly increased as they developed: the heliotropes were gradually replaced by sciophiles and those with wide ecological amplitude. 2) Phanerophytes, chamaephytes and hemicryptophyte were dominant in the understory communities; phanerophytes dominated in shrub layer, while chamaephytes and hemicryptophyte showed advantages in herb layer. 3) The understory diversity and evenness index increased as the development of P. tabulaeformis plantations; the richness and evenness in near-mature stands were significantly higher than those of middle-aged stands and young stands, respectively. The results indicated that the plantations had changed the physiognomy of community, not only improving the community structure, but restoring the biodiversity.