Dynamic Characteristics Of Forest Landscape Pattern In Wenyu River Basin

In order to explore the temporal and spatial dynamic characteristics of vegetation coverage in the Wenyu River Basin after the implementation of the two national key forestry projects,the Natural Protection Project and the Middle and Young Forest Tending Project.In turn,it provides a scientific reference for the precise improvement of forest quality and sustainable development.This research is based on five remote sensing images in 2000,2005,2010,2015,and 2020,combined with field survey data,and using machine learning classification methods.Using machine learning classification methods,in terms of vegetation coverage,composition and transfer of landscape element types,spatial distribution characteristics of forest landscape element types,and dynamic changes in landscape patterns,et cetera.We comprehensively analyzed the dynamic characteristics of the forest landscape pattern in the Wenyu River Basin in the past two decades.The research results can provide important references for future protection,utilization and management measures of forest resources in the Wenyu River Basin.The research results are as follows:(1)Vegetation coverage in the Wenyu River Basin is high and continues to grow.The vegetation coverage at each time point in the five-year interval since 2000 was 91.20%,96.40%,97.97%,97.95% and 98.35%,respectively.Among them,the medium and high vegetation coverage grades are the main vegetation coverage types,and the medium and the high vegetation coverage grades are the secondary vegetation coverage types.Coniferous forests,mixed coniferous and broad-leaved forests,broad-leaved forests,and shrubs in the vegetation landscape of the basin account for 79.73% of the total area of the area,and are the main types of landscape elements in the Wenyu River Basin.Since 2000,it has always been in the dominant position of the landscape.(2)The spatial distribution of various types of forest landscape elements in the Wenyu River Basin exhibits significant laws and characteristics.Among them,the actual distribution area of coniferous forest is larger in the altitude range of 1100m-2300 m,the proportion at the end of the period reaches 90.25%,and the potential tendency distribution range is1400m-2600m;The actual distribution area of the large slope range at the end of the gentle slope,slope and steep slope period accounts for 97.25%,and the potential tendency distribution range is in slopes and steep slopes;The actual distribution area is larger in the half-sun slope and half-shadow slope,accounting for 78.29% at the end of the period,and the potential tendency distribution range is in the shady slope and half-shadow slope.The actual distribution area of the coniferous and broad-leaved mixed forest is larger in the altitude range of 1100m-2100 m,the proportion at the end of the period reaches 91.97%,and the potential tendency distribution range is 1500m-2100m;The actual distribution area is larger in the range of gentle slopes,slopes and steep slopes,accounting for 96.48% at the end of the period,and the potential tendency distribution ranges are in slopes,steep slopes and steep slopes;The actual distribution area has a larger range of slope directions in semi-sun slope,semi-shady slope and sunny slope,accounting for 91.14% at the end of the period,and the potential tendency for all slope directions is basically the same.The actual distribution area of broad-leaved forest is larger in the altitude range of900m-2000 m,the proportion at the end of the period reaches 85.05%,and the potential tendency distribution range is less than 1300 m and greater than 1700m;The large slope range of the actual distribution area is gentle slopes,slopes and steep slopes,accounting for 93.24%at the end of the period,and the potential tendency for all slopes is basically the same;The actual distribution area has a larger range of slope directions in semi-sun slope and semi-shady slope,accounting for 76.45% at the end of the period,and the potential tendency for all slope directions is basically the same.The actual distribution area of shrubs is larger in the altitude range of 1100-2100 m,the proportion at the end of the period reaches 91.98%,and the potential tendency distribution range is 1100m-1500m;The large slope range of the actual distribution area is flat slope,gentle slope,slope and steep slope,accounting for 98.52% at the end of the period,and the potential tendency distribution range is flat slope,gentle slope,steep slope and dangerous slope;The larger range of the actual distribution area is half-sun slope,half-shadow slope and sunny slope,accounting for 93.69% at the end of the period,and the potential tendency distribution range is in the sun slope and half-sun slope.The larger range of the actual distribution area is half-sun slope,half-shadow slope and sunny slope,accounting for 93.69% at the end of the period,and the potential tendency distribution range is in the sun slope and half-sun slope.The large slope range of the actual distribution area is flat slope,gentle slope,slope and steep slope,accounting for 97.05% at the end of the period,and the potential tendency distribution range is flat slope,gentle slope,steep slope and dangerous slope;The actual distribution area has a larger range of slope directions in semi-sun slope,semi-shady slope and sunny slope,accounting for 91.60% at the end of the period,and the potential tendency distribution range is in the sun slope and semi-sun slope.(3)Under the implementation of two national key forestry projects,the Natural Protection Project and the Middle and Young Forest Tending Project,the degree of fragmentation of coniferous forests,mixed coniferous and broad-leaved forests,broad-leaved forests,shrubs,arable land,grasslands and bare land has decreased,and the degree of fragmentation of construction land and water areas that are susceptible to human disturbance has increased.The overall landscape connectivity of the Wenyu River Basin has increased,the original dominant forest landscape element types have increased,the distribution of various landscape element types has become more concentrated,and the degree of fragmentation tends to remain unchanged.(4)On the macro-scale,the overall succession direction between the landscape elements of the Hanyu River Basin is: bare land→grassland→shrub→broad-leaved forest→coniferous and broad-leaved mixed forest→coniferous forest.Among them,bare land,arable land,and grassland,which are greatly affected by human factors,have mutual transfer phenomena.