| Since the beginning of the 21st century,with the rapid urbanization and economic development,urban construction land has expanded rapidly,which not only occupies a large amount of cultivated land,but also brings about many environmental issues,such as forest land destruction,wetland shrinkage and water area reduction.In the early period,the Balance of Arable Land System(BALS)policy solved the problem of the quantity of cultivated land and paid attention to the area and quantity of cultivated land in the early stage,ignoring the quality and ecology of cultivated land.Therefore,taking food security,urban development and ecological security into consideration is a triple dilemma facing the sustainable development of land resources in China.In order to solve the development dilemma faced by the region,it is urgent to start with the problems emerging in the current land use,comprehensively analyze the conflict and relationship between the“three living”land of production,life and ecology,and put forward a scientific and reasonable land use and protection policy and system.Forest transformation theory holds that with the development of social economy,the forest area of developed or developing countries and regions may change from net decrease to net increase.However,the increase of forest area in these countries or regions may be at the cost of the decrease of forest area in other regions,and the spatial correlation of forest area change has not been paid attention to at present.Since 2000,China has implemented many policies to increase forest area and protect the environment,so that the overall forest area and forest coverage have increased steadily.However,the study found that the phenomenon of deforestation in Zhejiang Province,an economically developed region in eastern China,is relatively severe,which has attracted the special attention of international non-governmental organizations such as domestic focus interviews and Greenpeace.Exploring the temporal and spatial dynamics of deforestation in Zhejiang,analyzing its influencing factors and formation mechanism,and investigating its impact on ecosystem services are not only of great significance to the optimization of land space and the construction of ecological civilization,but also help to enrich the theory of forest transformation and promote the development of relevant theories.Based on multi-source data such as remote sensing,statistical data and field investigation,Google Earth Engine(GEE)and GIS spatial analysis are used to further investigate the temporal and spatial evolution characteristics of deforestation change in Zhejiang Province from 2000 to 2020.Simple correlation analysis and Geographic Weighted Regression model(GWR)are used to analyze the influencing factors of deforestation and the spatial differentiation characteristics of influencing factors in Zhejiang Province,to quantitatively explore the transition among the land for ecology,living and production,this paper uses the telecoupling framework to analyze the correlation mechanism of the BALS policy between deforestation and urbanization.Based on this,use the In VEST model to quantify the changes of ecosystem service caused by deforestation,explore the future land use status under different scenarios based on the flux model,and finally analyze the problems existing in the current land policy and its implementation,and put forward corresponding suggestions.The main conclusions of this study are as follows:(1)Based on Hansen’s global forest change data,cross-validation of multiple random sample data and field investigation,this paper analyzes the temporal and spatial variation characteristics of deforestation in Zhejiang Province from 2001 to 2020,and investigates the temporal and spatial relationship between deforestation location and terrain,as well as the distance relationship with nature reserves and KBA.The results show that the forest loss in Zhejiang Province is relatively severe.Deforestation is mainly distributed in the economically underdeveloped and mountainous cities and counties in the southwest of Zhejiang Province,showing a trend of first increasing and then decreasing over time.From 2001 to 2020,the total net loss of forests in Zhejiang Province was 290,000 hectares;In 2008,the peak of forest loss was nearly 27,000hectares,which has remained high since then,decreased slightly,and the annual loss remained at a high level of about 15,800 hectares on average.In terms of vertical distribution,deforestation is mainly concentrated on the mountaintop and hillsides,but the height of deforested forest land decreases with time.The average altitude of forest loss area decreases from 553.94 meters in 2001 to 303.04 meters in 2020,and the slope decreases from 23.27 degree to 15.01 degree,of which the slope and altitude of forest loss patch in 2008 are the maximum.The deforestation area is positively correlated with the distance to the nature reserve and KBA.When the deforestation patch and its distance increase,the deforestation area will increase.There is still a small amount of deforestation in the National Nature Reserve and KBA area,indicating that ecological protection in Zhejiang Province faces great challenges.(2)Aiming at the influencing mechanism of deforestation in Zhejiang Province,the spatial differentiation characteristics of deforestation influencing factors are explored using the GWR Model.The internal relationship between policy and urbanization is analyzed using a telecoupling framework.The results show that the spatial heterogeneity of the influencing factors of deforestation in all districts and counties of Zhejiang Province is significant,the GDP is negatively correlated,the distance to the main rivers is positively correlated,and the population density does not show a significant positive or negative relationship.In addition to the negative correlation between socio-economic factors and deforestation,terrain,climate,transportation and location factors are positively correlated with deforestation.GWR Model analysis shows that there are regression coefficients in each district and county with considerable variability,and each index’s influence degree and action trend in different districts and counties are quite different.There is a negative correlation between GDP and deforestation,and the regression coefficient shows an increasing trend from south to North in space;The impact of population density on deforestation does not show a significant positive and negative relationship,and the spatial heterogeneity is very significant.Specifically,from the spatial point of view,the regression coefficient shows an obvious increasing trend from west to East,and changes from a negative value to a positive value;The main distance to the river has a positive correlation with deforestation,and the regression coefficient increases from south to North in space.There is a long-range coupling relationship between deforestation in remote mountainous areas of Southwest Zhejiang Province and urbanization in coastal areas of the province.From 2000 to 2020,the reduction of forest area in Zhejiang Province was accompanied by the expansion of urban land and the shrinkage of cultivated land.According to the BALS policy,the occupation of cultivated land by the development of Hangzhou city is to“compensate”the loss of cultivated land in Hangzhou by cutting down the forest Lishui to expand cultivated land.The telecoupling framework can well explain the patterns and mechanisms of deforestation in Zhejiang Province.(3)In view of the implementation effect of the BALS policy,the changes of key ecosystem services such as carbon sink,soil conservation and food production in Zhejiang Province from 2000 to 2020 were quantitatively evaluated based on the In VEST model.The study found that deforestation and BALS policy have an important impact on the ecological environment and food security,mainly in reducing carbon sink function,the increase of soil erosion,the decline of food production and so on.Using the In VEST model to quantify ecosystem services in Zhejiang Province,it is found that forests are the main body of surface carbon sequestration and soil conservation functions in all land types in Zhejiang Province.Since 2000,carbon storage has decreased by 30.54 TG,indicating that the carbon sequestration capacity of the ecosystem in Zhejiang Province has been further reduced.Since 2000,soil erosion has increased slightly,of which more than 85%of the areas belong to micro erosion areas.The erosion intensity and amount in southwest mountainous areas are the largest in the province,indicating that deforestation and land reclamation in mountainous regions easily cause soil erosion.Soil erosion in mountainous areas with high altitudes and large topographic relief is also intensive,which is more severe than that in other areas.The topographic distribution of carbon storage,soil erosion and soil conservation is similar to deforestation.(4)Based on the FLUS model,the spatial simulation analysis of land use change under the future conventional urbanization scenario,cultivated land protection scenario and ecological protection scenario in Zhejiang Province is carried out.The results show that in 2030,the structure of land use types in Zhejiang Province is relatively stable,and forests are still the main land type in Zhejiang Province,followed by cultivated land and construction land.Conventional development means that under the scenario of continuing urban development,the forest area decreases,the cultivated land area continues to decrease,the construction land area continues to increase,and the dynamic degree reaches 2.95%.Under the scenario of cultivated land protection,the cultivated land area increased by 407 km~2,with a growth of 0.15%.Except for the slight increase of construction land,other land types such as forest land decreased slightly.Under the ecological protection scenario,the ecological land of forest and grassland are effectively protected,and the growth dynamics of forest reach 0.56%.Compared with the conventional development scenario,the area of forest land increases more and the increased range becomes larger;The increase rate of construction land decreases and the decrease rate of cultivated land increases.Forest land only increases in the ecological protection scenario,while cultivated land only increases in the cultivated land protection scenario,while construction land continues to expand in any scenario.In the process of land use in the future,it is necessary to form a comprehensive and balanced utilization and ecological protection system guided by scientific planning to promote the sustainable development of land use. |
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