Abstract:

To identify the crucial effects of spatial structure on understory shrub species diversity, the Quercus secondary forest in Badagong Mountain is studied. The spatial structure of forest stand is evaluated by calculating the size ratio, mixing degree, aggregation index and openness index, and the understory shrub species diversity is evaluated by calculating the Margalef index, Pielou index and Auclair index. The Pearson correlation coefficient analysis is adopted to explore the correlation between the indexes. The finding indicates that the openness and aggregation index of natural secondary forest of Quercus species in Badagongshan are two main factors relevant to the species diversity of undergrowth shrubs, a positive correlation can be found both between the openness index and Pielou index, and between the aggregation index and Auclair Goff index. With the increase of the openness index, Pielou index increases correspondingly, which means the species evenness of understory shrubs is increased. With the growth of Quercus species aggregation index, Auclair Goff index grows correspondingly, which implies the species of undergrowth shrubs is diversified. Therefore, to improve the species diversity of understory shrubs in natural secondary forest of Quercus species in Badagongshan, we should focus on adjusting the structure of tree species and the pattern distribution of forest space, especially from aspects of the tree openness and aggregation.

Key words: spatial structure of forest, species diversity, underbrush shrubs, simple correlation analysis