Plant Diversity And Evaluation Of Seedling And Sapling Regeneration For The Juglans Mandshurica In Songshan

This study took the forests of Juglans mandshurica in Songshan Area as its researching object,estimated the number of species of Juglans mandshurica in the research area through the different approaches such as sample survey,remote sensing monitoring.etc.It adopted the method of typical sampling and four kinds of diversity index to analyze the composition and diversity of shrub and herb species;It classified the seedlings and saplings of Juglans mandshurica through establishing the grade standard;Adopting the method of variance/mean ratio,it was tested by T-check and refer to four concentration index meanwhile to evaluate the spatial distribution pattern,and made the comparative study to the seedlings and saplings of different levels.It mainly draw the following conclusion:Firstly,it was found that there were 65 plaques of Juglans mandshurica in Songshan National Nature Reserve Zone with a total of 396.47 hectares,which is mainly distributed in valleys of DaZhuangke Village and LanJiaogou.The forest of Juglans mandshurica were mainly mid-maturation trees on the aspect of plantation age composition,with mature forest as the second place and the young forest as the least.Secondly,with the increase of forest age,shrub layer and herb layer plants under the Juglans mandshurica forests had apparent space-time evolution trend:the categories of shrub layer plant gradually increase while the herb layer species gradually reduce;the herb layer under the Juglans mandshurica forests in young forest mainly took the Carex lanceolata,Spodiopogon sibiricus,Aconitum carmichaeli and Agrimonia pilosa as dominant species,and took Rabdosia japonica and Chelidonium majus as dominant species in the middle and later period.In the shrub layer,the Rhamnus parvifolia,Deutzia parviflora var.prviflora and Syringa pubescens were the main dominant species.With the increase of forest age,the species diversity index of the shrub layer increased continuously,and the evenness index of herb layer increased continuously and the other index declined continuously as the forest age increased.Thirdly,the features of human factors interference,animals eating,pests damage and crown density of Juglans mandshurica,were the important reasons of low density of seedlings of level 1 and level 2.From level 3 to level 4,the seedlings of Juglans mandshurica entered a comparative stable state,which has apparent lower death rate and the tendency of growing into mature trees.The seedlings and saplings of Juglans mandshurica within the research area had obvious features of aggregation distribution.As the height of seedlings and saplings increases,the aggregation distribution gradually decreases on the whole.