Comprehensive Evaluation Of Forest Site Quality Based On Digital Soil Mapping Technology

Forest site quality is the basic work of forest cultivation.The quality of forest site not only affects the function of forest,but also affects the sustainable development of global ecological environment and forest resources.However,the traditional minimum unit of forest site quality evaluation is still based on the polygon unit of site type division,and the forest site division is not precise enough,the evaluation factors are not comprehensive enough,especially the lack of detailed soil attribute spatial data.In order to meet the needs of precision forestry,how to obtain the detailed evaluation factors and detailed soil spatial information will be the focus of attention in the future.With the continuous development of digital soil technology,it not only greatly improves the mapping accuracy and reduces the mapping cost,but also provides a scientific means for quickly and accurately obtaining the site factor information,and provides technical support for multi factor and multi-level comprehensive evaluation.Jiyuan Nanshan forest farm is located in the rocky mountainous area of North China,with thin soil layer and difficult afforestation.Therefore,it is of great significance to accurately evaluate the forest site quality in this region.Taking Nanshan forest farm in Jiyuan as the research area,Latin hypercube sampling method was used to select field sample points.Firstly,the terrain factors such as slope,aspect,plane curvature,profile curvature and terrain humidity index are extracted from DEM data(Then,the vertical drought index,surface temperature,vegetation coverage and NDVI site environmental factors distribution map of the study area were obtained based on remote sensing image data.Finally,the forest site quality of Jiyuan Nanshan forest farm was evaluated,mapped and classified by grey correlation method Analysis.It mainly includes the following two aspects:(1)Fuzzy c-means based on soil landscape model(The results show that FCM clustering method is an efficient,low-cost,high prediction accuracy and stable prediction model This paper presents a new method of forecasting and mapping.(2)Based on the prediction map of main soil properties and the distribution map of forest environmental factors in the study area,the spatial distribution information of site quality of Nanshan forest farm in Jiyuan was comprehensively evaluated by grey correlation method.The results showed that the site quality grade of the study area was mainly grade 4 site,accounting for 54.38%of the total area,followed by grade 3 site,accounting for 26.91%of the total area,and grade 1,2 and 5 sites accounted for a small proportion.Grade 1 site accounted for 5.27%of the total area,grade 2 site accounted for 8.96%of the total area,and grade 5 site accounted for 4.48%of the total area.The digital soil mapping technology based on FCM can obtain the high precision soil attribute distribution map based on a few sampling points,which provides accurate soil spatial information for site evaluation.Then,it provides scientific data base for forest resource management and sustainable management of Nanshan forest farm in Jiyuan,and helps to improve the forest quality accurately.