Spatial Variability Of Site Factors And Micro Site Classification In Arid And Barren Mountains Of South Central Shandong Province

Arid and barren mountainous area is one of the most difficult sites in Shandong Province,and poor site conditions are the important factors restricting vegetation restoration in this area.However,in the process of vegetation restoration,the site microenvironment mostly affects the growth and community development of trees.The traditional large-scale site classification method is not enough to meet the requirements of small-scale community construction.Based on this,this paper takes two typical arid and barren sites(gneiss mountain area and granite mountain area)in Shandong Province as the objects,and obtains high-precision remote sensing images and digital elevation models based on UAV aerial survey technology and photoscan platform;The information of multi-dimensional stress factors was obtained through field investigation and laboratory analysis;By using ArcGIS technology to interpret the site factors and analyze the spatial variability,two types of site micro sites are finally divided.The purpose of this study is to explore a set of methods that can accurately and quickly divide the types of micro sites in arid and barren mountains,and provide a theoretical basis for vegetation restoration and accurate plant community allocation in difficult sites.The main results are as follows(1)Taking rock type as the first-order classification factor,terrain factor(slope,aspect and altitude)as the second-order site factor,and soil factor(IFI,soil thickness and soil water holding capacity)as the third-order site factor,the micro site classification system was constructed.The results show that the soil factors(soil nutrients,soil layer thickness and soil water holding capacity)in gneiss and granite-mountains are heterogeneous in spatial dimensions(slope,aspect and altitude).(2)ArcGIS interpolation module was used to analyze soil factors.The cross validation results show that the Collaborative-Kriging interpolation method is used for soil water holding capacity,the IDW method is used for soil thickness,and the Ordinary-Kriging interpolation method is used for soil nutrient status in Gneiss mountains;The results show that the inverse IDW method is used for soil water holding capacity and soil nutrient status,the Ordinary-Kriging interpolation method can be used to predict the changes of soil thickness.Based on this,the thematic maps of gneiss and granite are made.1600 quadrats(10m×10 m)of gneiss-mountain area are obtained 8 micro site type groups and 43 micro site types.2826 quadrats(10 m×10 m)of granite-mountain are obtained 8 micro site type groups and 48 micro site types.(3)Compared with the field survey results,except for 38 of 210 survey quadrats,the others are basically consistent,and the division accuracy is 81%.In a word,the classification of micro site types in gneiss-mountain and granite-mountain in Shandong Province is consistent with the actual site conditions,which provides a scientific basis for the accurate allocation of plant communities in the region.Based on UAV aerial survey combined with field survey,site type can be divided more accurately,which can improve the efficiency of forestry work to a certain extent.