Study On The Coupling Of Forest Carbon Density And Landscape Pattern In Haikou

Whether forest carbon density and forest landscape pattern develop harmoniously is crucial to the forestry and ecological environment construction.The purpose of this study is to explore the coupling and co scheduling between stand carbon density and forest landscape pattern index in Haikou City.In this study,the forest of Haikou City is taken as the research object.Based on the secondary survey data of forest resources of Haikou City in 2010 and 2015,the forest type is divided,and the forest carbon density and forest landscape pattern index are calculated.The coupling coordination degree model is constructed by the quantified forest carbon density and comprehensive landscape pattern index,and the coupling coordination is calculated.Finally,the discussion is made the influence factors such as distance from road,distance from water source,slope,soil organic carbon content,etc.on the coupling co operation.The results of this study are as follows:(1)From 2010 to 2015,the broadleaf mixed forest increased the most in stand area,and the broadleaf mixed forest increased the fastest in carbon storage and carbon density.The average annual carbon storage increased by 202382.44t,and the annual carbon density increased by 6.79m3/ha.There is a positive correlation between carbon storage,carbon density and the area and volume of different forest landscape types.Comparing the canopy density,age group structure,carbon storage and carbon density in 2010 and 2015,.it was found that with the increase of stand density and age group structure,carbon storage and carbon density also increased.(2)According to the landscape pattern indexes of Haikou City in 2010 and 2015,it was found that the Contag decreased,the density of patch(PD),the shape index of landscape(LSI)and the resolution index(vision)increased,and the resolution index(vision)value exceeded 0.7,indicating that the overall fragmentation degree of the forest landscape pattern of Haikou City was high,and the comprehensive landscape pattern index was poor.By comparing the index distribution of each individual landscape pattern and the index distribution map of the comprehensive landscape pattern,it is found that the areas of good and bad landscape reflected in the index distribution map of the comprehensive landscape pattern are basically consistent with the index of each individual landscape pattern.(3)Combined with the spatial distribution map of coupling coordination degree,the spatial distribution map of carbon density and the spatial distribution map of comprehensive landscape pattern,it is found that some areas with better comprehensive landscape pattern index have lower coupling coordination degree because of the lower carbon density of the stand.In other words,though the comprehensive landscape pattern index is better in some regions,their carbon density is low,so their coordinated development degree is lower.Similarly,the carbon density of some regions is better,while the comprehensive landscape pattern index is poor,which leads to the lower coupling coordination degree of the region.(4)In 2010,the order of the coupling level of Haikou City according to the occupied area size is moderate coordination coupling>low coordination coupling>high coordination coupling a>extreme coordination coupling,while in 2015,the order of the coupling level is low coordination coupling>medium coordination coupling>high coordination coupling>extreme coordination coupling.According to the area variation of coupling coordination degree,the coupling and coordinated development degree between forest carbon density and forest landscape pattern in Haikou City is reduced.As for the high coordination coupling,the order of the proportion of the area of each forest type in the high coordination coupling in 2010 is:tropical forest>mangrove forest>eucalyptus forest>broad-leaved mixed forest>other broad-leaved forest>bamboo forest>shrub forest>economic forest,while the order of the proportion of the area of each forest type in the high coordination coupling in 2010 is broad leaved mixed forest>mangrove forest>eucalyptus forest>tropical forest>shrub forest=Caribbean pine=economic forest=other hard broad-leaved forest=0.It can be seen that the area of forest types which react high coordination coupling in Haikou decreased in 2015.(5)The geographic weighted regression model can reflect the influence degree of each variable in different geographical locations on the region.After eliminating the multiple collinearity influence factors,the conclusion that the influence degree on the coordinated coupling development between carbon density and forest landscape pattern in Haikou City of variables including distance from water source,distance from road,slope,soil organic carbon content and other factors can be draw.As calculated result,the order of their influence is distance from road>distance from water source>slope>soil organic carbon content.