Study On Plant Diversity Of Larix Principis-rupprechtii Plantation In Saihanba

Saihanba forestry ecnter lies in the northest of Hebei province. Its vegetation regionalization belongs to forest-steppe ecotone whose typical vegetation communities are meadow steppe, mixed wood and deciduous broadleaved forest. The special natural geographical environment leads to the complex and rich diversity and floristic composition.Taking the main forestation tree species(Larix principis rupprechtii) of Saihanba forestry ecnter as the research object and using sample plot investigation method, Larix principis rupprechtii understory vegetation community Characteristics and importance values are analyzed fully. Correlative analysis, grey relational analysis and regressive analysis methods are used to study the species diversity of different forestry centers of Saihanba. According to both binary and numerical data, the species similarity is studied. Canonical Correspond Analysis and Detrended Canonical Correspond Analysis are taken to study the relation of distribution of understory vegetation and environment factors. The study results are as follows:(1) There are 97 understory herb vascular bundle plants, belonging to 30 families and 77 genuses. Among them, seed plants belong to 28 families and 75 genuses and 95 species. There is no large family.(2) Carex rigescens (Franch.) V. Krecz, Erysimum cheiranthoides L, Cleistogenes chinensis (Maxim.) Keng has the larger important values in Sanxiang forestry center; Cleistogenes chinensis (Maxim.) Keng, Carex rigescens (Franch.) V. Krecz, Scutellaria scordifolia Fisch, Viola verecunda A. Gray are the dominant species of the community in Dahuanqi forestry center; Carex rigescens (Franch.) V. Krecz, Geranium krameri Franch. et Sav, Cleistogenes chinensis (Maxim.) Keng dominate absolute advantage in Qiancengban forestry center.(3) Different species diversity indexes have the higher Correlation Degree with the environment factors. The same factor has different sorting with different species diversity index which shows that the relation between environment factors and diversity is viry complicated.(4) Binary attribute data Cj and Cs have the same change trend with binary quantity data Cn. Among them, Similarity index of Sanxiang-Dahuanqi is biggest,βdiversity is smallest. Dahuanqi-Qiancengban's is second. Sanxiang-Qiancengban is smallest; its species substitute is very obvious and it has the biggest.βdiversity .(5) CCA and DCCA are put up to the same community. The result shows that the relation of DCCA with factors is weaker than CCA, but DCCA's result can reflect a nearer real result better.