Study On Composition Of Six Communities And The Diversity Of Understory Plant Species In The Second Phase Of Forestry Project In Sandification Combation Program In Beijing

This study carried out a comprehensive and in-depth field investigation of the vegetation in the mountainous area of Beijing,which is part of the Sanddification Combating Program for Area in Vicinty of Beijing Phase II Forestry Engineering Area.According to the data of 18 sample plots in the field survey in 2019,six planted communities were screened,the understory vegetation diversity index of different communities was calculated,The community species composition and undergrowth plant diversity were studied.In addition,the correlation between different slope direction,slope and slope position and species diversity was analyzed and studied to provide certain reference value for vegetation restoration and sustainable forest management of the second-phase forestry project,and the following conclusions were drawn:(1)According to the appearance characteristics of vegetation and the frequency of vegetation,the community is named after the dominant species.There are six communities in the plot: Platycladus orientalis,Pinus tabulaeformis,Apricot,Luan,Oak,and Platycladus orientalis communities.The shrubs have a higher frequency of legumes and buckthorns.There are Asteraceae and Gramineae,and the sun and drought-resistant vegetation dominates.(2)In the six typical communities,the Patrick index of shrubs and shrubs is the same as that in the oak and apricot communities.Among the remaining communities,the herb layer had the highest Patrick index,which made an important contribution to the species diversity composition of the community.The diversity index values are the highest in the herb layer,the lowest in the shrub layer and the lowest in the tree layer.Through single factor analysis of variance,it was concluded that the species diversity indexes of the six communities were significantly different(P<0.05).(3)According to the survey results,there were 59 vegetation species in the community,including 20 shrub species,accounting for 34%,and 39 herb species,accounting for 66%.The richness of vegetation species is generally the most abundant in the herbaceous layer,the lowest in the abundance of trees and the middle of shrubs.The species with the highest value of shrub grass vegetation in each community are different.(4)In the six communities,the Shannon-Wiener index decreases gradually with the rise of slope position.The Pielou uniformity index is lower in all shrub layers of the community,and the downhill slope is larger than the uphill slope.In the herb layer,the downhill slope is smaller than the uphill slope.In the shaded slopes,Platycladus orientalis community and Platycladus orientalis community,the diversity index of the shrub layer is higher than that of the sun slope.The condition of the herb layer is the same as that of the shrub layer.It can be predicted that the above two communities will develop well on the shaded slope.In the remaining communities,the diversity index of understory shrubs and grasses is that the sun slope is better than the shade slope,and it can be predicted that these communities will grow well on the sun slope.(5)There is a significant correlation between different slope positions,aspect and diversity index;and the correlation between slope aspect and diversity index is more significant.