Forest Land Types Research Articles

Spatial Pattern and Influence Mechanisms of Forest Land Quality under the Background of Carbon Peaking and Carbon Neutrality: A Case Study in Kaizhou District, Chongqing, China

Since the goals of carbon peaking and carbon neutrality have been established, forest carbon sinks have garnered significant attention. As a fundamental component of forest carbon sinks, the quality of forest land significantly influences the carbon sink capacity of forests. This study utilized Kaizhou District, Chongqing City, a typical forest area as a case study, and used the correction method, factor method, CASA model, landscape ecology indexes, and canonical correlation analysis to evaluate the level of forest land quality and reveal the spatial distribution pattern and influencing mechanisms of forest land quality. The results showed that: (i) The quality index of public welfare forest land was distributed in [37.89, 148.15], and each quality level was diversified in space. The quality index of commodity forest land was distributed in [40.00, 92.67], and some high-quality forest land appeared in the transition zone of each region; (ii) The forest land quality index and the amount of net primary productivity passed the correlation test. Primary net productivity was higher on forest land with a high-quality index and lower on forest area with a low-quality index; (iii) public welfare forest land was mainly positively affected by community structure, average annual precipitation, average annual temperature, and soil moisture. Commodity forest land was mainly positively affected by average annual temperature, soil moisture, and slope aspect. However, landform had a significant negative impact on the two types of forest land. Given these findings, we also proposed a series of measures aimed at promoting the sustainable development of research on regional forest land.

Knowing the lay of the land: changes to land use and cover and landscape pattern in village tank cascade systems of Sri Lanka

Social-ecological systems (SESs) possess a great diversity of land use and land cover (LULC) types with unique assemblages of biodiversity and ecosystem services. However, LULC changes due to landscape fragmentation are emerging as major threats to the system productivity of SESs around the world. This study examined changes to LULC extent and landscape patterns in the Village Tank Cascade Systems (VTCSs) of Sri Lanka using satellite imagery and GIS techniques between 1994 and 2021. Multispectral Landsat images (5 TM and 8 OLI/TIRS) obtained from Google Earth Engine were classified using machine learning algorithms. Overall accuracies obtained were 85.9% (1994) and 88.6% (2021). The LULC change matrix and spatial pattern metrics were used to examine LULC and landscape pattern change dynamics over the VTCS landscapes. LULC change matrix results revealed that forest, which is the dominant LULC class covering 73.7% of the total land area was reduced by 206,725 ha due to transformation into agricultural (70.43%) and scrub (24.33%) lands between 1994 and 2021. Over this time landscape pattern of the VTCS has gradually changed from forest to agricultural land-dominated landscape, with forest and agricultural land types showing a significant negative correlation (p < 0.001; R2 > 0.868), particularly in the southeastern region. Landscape patterns were analysed based on eight spatial metrics calculated at both the landscape and class levels using FRAGSTATS spatial pattern analysis software. At the landscape level, the structure became more dispersed and complex in shape. Heterogeneity was noted to have gradually increased with weakening connectivity, whereas the fragmentation process had gradually accelerated. At the class level, the dominance of forest patches decreased, fragmentation and isolation increased, and connectivity and shape complexity reduced leading to the loss of fragmented forest habitats. The number of patches within the agricultural class increased and became more aggregated and complex in shape. Landscape performance indicators show that VTCSs have experienced a gradual loss of environmental sustainability. Assessment of LULC along with fragmentation can help to monitor the spatial pattern impacts that determine ecological integrity. Thus, the study provides scientific guidance for ecological restoration in degraded VTCSs to effectively improve ecological productivity.

A Two-Layer SD-ANN-CA Model Framework for Multi-Typed Land Use and Land Cover Change Prediction under Constraints: Case Study of Ya’an City Area, Western China

Land use and land cover change (LUCC) prediction of cities in Western China requires higher accuracy in quantitative demand and spatial layout because of complex challenges in balancing relationships between urban constructions and ecological developments. Considering city-level areas and various types of land use and land cover, existing LUCC models without constraint or with only loose demand constraints were impractical in providing evidence of high accuracy and high-resolution predictions in areas facing fierce land competition. In this study, we proposed a two-layer SD-ANN-CA model to simulate and explore the LUCC trend and layout predictions for 2018, 2028, and 2038 in Ya’an City, Western China. The two-layer structure with an upper layer of the SD model and a lower layer of the ANN-CA model, as well as the advantages of all three methods of system dynamics (SD), artificial neural network (ANN), and cellular automata (CA), have allowed us to consider the macro-level demand constraints, meso-level driving factors constraints, and the micro-level spatial constraints into a unified model framework. The simulation results of the year 2018 have shown significant improvement in the accuracy of the ANN-CA model constructed in our earlier work, especially in types of forest land (error-accuracy: 0.08%), grassland (error-accuracy: 0.23%), and construction land (error-accuracy: 0.18%). The layout predictions of all six types of land use in 2028 and 2038 are then carried out to provide visual evidence support, which may improve the efficiency of planning and policy-making processes. Our work may also provide insights into new ways to combine quantitative methods into spatial methods in constructing city-level or even regional-level LUCC models with high resolution.

Spatiotemporal distribution patterns of soil ciliate communities in the middle reaches of the Yarlung Zangbo River

Introduction: Soil ciliates, as protozoa, play a crucial role in biogeochemical cycling and the soil food web, yet they are highly sensitive to environmental fluctuations in soil conditions. The diversity and biogeographic characteristics of soil ciliates in the Tibetan Plateau remain poorly understood. As part of a regional survey focused on soil ciliate diversity, we investigated the composition and spatiotemporal variations of soil ciliate communities along the Yarlung Zangbo River, a representative soil habitat in the Tibetan Plateau.Methods: A total of 290 soil samples were collected from four habitat types of grassland, shrubland, forestland and wetland in the middle reaches of the Yarlung Zangbo River during the wet and dry seasons, and 138 species of ciliates were identified.Results: Soil ciliate diversity exhibited greater variation across habitat types than seasons. Moreover, soil ciliate diversity was higher during the wet season compared to the dry season, with the wetland habitat showing the highest diversity and the grassland habitat displaying the lowest. We observed spatiotemporal heterogeneity in the composition of soil ciliate communities across different seasons and habitat types. Notably, Litostomatea, Karyorelictea, and Prostomatea predominated in ciliate communities during the wet season and in grassland habitat. Phyllopharyngers dominated during dry seasons and in forested regions, while Spirotrichea species were prevalent in wetland and forested areas. The co-occurrence network analysis showed that soil ciliate community was more complex in wet season than in dry season, and the stability of soil ciliate community in wet season was higher than that in dry season. The stability of soil ciliate community in wetland was higher than that in forestland, shrubland and grassland, and the anti-interference ability was stronger. Soil temperature (ST), Total nitrogen (TN), Soil organic matter (SOM) and Soil water content (SWC) are important factors affecting the structure of soil ciliate community. By influencing the metabolic rate and nutrient acquisition of soil ciliates, the distribution pattern of soil ciliate community diversity in the middle reaches of Yarlung Zangbo River is shaped.Discussion: In summary, this study revealed the distribution pattern of soil ciliate community diversity in the Yarlung Zangbo River Basin, and the key factors affecting the spatial and temporal differences and stability of the community, enhancing our understanding of how ciliates adapt to environmental conditions in soil habitats across the Tibetan Plateau.

A Spatial Mixture Model for Spaceborne Lidar Observations Over Mixed Forest and Non-forest Land Types

A Spatial Mixture Model for Spaceborne Lidar Observations Over Mixed Forest and Non-forest Land Types

CONTAMINATION OF LANDS AND HABITATS OF WILD UNGULATES BY EGGS AND LARVIES OF HELMINTHS OF THE STRONGYLATA SUBORDER

Different types of forest land are not the same, as are the places of circulation of eggs and larvae of helminths of the Strongylata suborder. Plant formations with a low risk of infection are young pine forests, middle-aged and old pine forests, old mixed forests, spruce forests. Potentially dangerous in terms of infection are bushes of river floodplains and forest meadows. Plant formations with a high risk of infection are young mixed forests, middle-aged mixed forests with undergrowth. The most dangerous for infection are swampy forests and forest swamps. The degree of contamination and accumulation of invasive larvae of helminths of the Strongylata suborder in different lands and habitats is different and differs depending on the season of the year. The most favorable for mass infection is the end of summer, the beginning of autumn, namely August-September. The distribution of eggs and larvae of helminths of the Strongylata suborder in forest lands has a mosaic character. The number of plots depends on the areas preferred by wild ungulates. The movement of wild ungulates across the land occurs also under the influence of the anthropogenic factor, which affects the distribution of infection. If we know the habitats of wild ungulates, we can assess the degree of contamination by eggs and larvae of species and characterize the risk of infecting wild ungulates with them. The number of eggs and larvae of helminths of the Strongylata suborder in excrement may vary over time depending on weather conditions. Infection with helminths of the suborder Strongylata occurs through the trophic links of wild ungulates. The addition of young grass vegetation to the diet of wild ungulates in spring leads to an increase in eggs and larvae of helminths of the Strongylata suborder in excrement. In the autumn season, when wild ungulates switch to rough forages, the number of eggs and larvae of helminths of the Strongylata suborder in excrement decreases.

Responses of Soil C, N, and P Stoichiometrical Characteristics, Enzyme Activities and Microbes to Land Use Changes in Southwest China Karst

The present study aim is to elucidate the effect and influencing mechanism of land use change on soil C, N, and P stoichiometric characteristics, soil enzyme activity and the microbial community in the karst ecosystem of southwest China. The three typical successive evolution land use types of original forest land, slope farmland and shrub-grassland were selected as the study objects in the present study. Additionally, the change in the laws and relationships of soil, the C, N, and P stoichiometric characteristics, the five soil enzyme activities of urease, sucrose, alkaline phosphatase, amylase and protease, and soil microbial community during the land use evolution process were studied. Results showed that (1) during the evolution process of the three land use types, soil C, N, and P stoichiometric characteristics, enzyme activities and microbial PLFAs (phospholipid fatty acids) varied significantly or extremely significantly; (2) in the three land use types studied, there were significant or extremely significant correlations between soil C, N, and P stoichiometric characteristics, enzyme activities and microbial PLFAs; (3) the ecological project of returning farmland to woodland had remarkable ecological effects on increasing soil C and N sink, repairing soil microbial community and improving soil quality; (4) artificial afforestation should be used as the most important and preferential measure for karst vegetation restoration and reconstruction. The present results not only provided scientific bases for land sustainable utilization, vegetation restoration and reconstruction, but also had important value in reducing the release and increasing the sequestration of soil C and N in karst ecosystems of Southwest China.

Soil Quality Assessment of Several Kinds of Typical Artificial Forestlands in the Inner Mongolia Basin of the Yellow River

Located in the middle and upper parts of the Yellow River Basin, Qingshuihe County, Inner Mongolia, is a typical hilly and gully loess region and one of areas under the implementation of major ecological protection and restoration projects in the key ecological areas of Yellow River. Scientifically and accurately constructing a soil quality evaluation system for different types of artificial forest land and evaluating their soil quality are essential because they help optimize the structure of artificial forest land and improve the soil quality in the loess hilly area of Yellow River Basin. In this study, soil from four representative types of artificial forest land in the middle and upper reaches of the Yellow River Basin in Inner Mongolia was selected as the study object, with natural non-forest land as the control. Sixteen soil property indices in five classes, namely, soil texture, acid–base properties, moisture, pore, and nutrient, were screened using correlation analysis, minimum dataset (MDS), and principal component analysis methods, and an MDS of soil quality evaluation was constructed. Results showed that (1) the evaluation indices of artificial forest land soil quality based on the MDS included total potassium content, total phosphorus content, alkali-hydrolyzed nitrogen content, total nitrogen content, sand content, moisture content, and non-capillary porosity. (2) No significant differences were observed in the soil quality index among the MDS, total dataset, and significant dataset (SDS), all of which exhibited significant positive correlations. (3) The soil quality of the different types of forest land was sorted from high to low as follows: mixed coniferous and broad-leaved forests, larch forests, mixed arbor and shrub forests, Armeniaca sibirica forests, and natural non-forest land.

Temporal and spatial changes in land use and ecosystem service value based on SDGs' reports: a case study of Dianchi Lake Basin, China.

Understanding the impact of land use and ecosystem services on sustainable development goals is a key to achieving sustainable development goals (SDGs). Taking Dianchi Lake Basin as the research area, land use data from five periods, 2001, 2005, 2010, 2015, and 2019, were analyzed using the dynamic equivalent method to determine ecosystem service value (ESV) and hot spot analysis method to explore temporal and spatial changes in ESV in Dianchi Lake Basin. Three sustainable development goals, SDG15.1.1, SDG15.2, and SDG15.3.1, were selected to quantitatively analyze the impact of land use change in Dianchi Lake Basin. The results showed that (1) in the 20-year study period, the main land use types in Dianchi Lake Basin were forest land, cultivated land, construction land, and water area. In the land transfer, the largest amount of land transferred out is cultivated land, accounting for 35.50% of the total transferred out amount. It is transferred to construction land, resulting in significant expansion of construction land, nearly twice as much. (2) The SDG15.1.1 index of three forest land types in Dianchi Lake Basin showed a downward trend, and the total forest land decreased from 45.36 to 41.80%, with a cumulative decrease of 3.56%, of which 2.35% was caused by the transformation from open forest land to other land types. For watershed SDG15.2 and SDG15.3.1 indicators, all were degraded, but the degradation of high forest (SDG15.2) was the most obvious. (3) From 2001 to 2019, the total ESV in Dianchi Lake Basin initially decreased and then increased before decreasing again, with an overall decrease of 3.687 billion yuan. The ESV in the study area was high in the middle and low in the periphery, and the water area dominated by Dianchi Lake was the highest value area. (4) From 2005 to 2019, the spatial displacement relationship between cold and hot spots dominated by Dianchi Lake was corresponding and obvious, during which the ESV fluctuated violently. This study provides a basis for the sustainable development and ecological construction in typical urbanized watershed.

Research on Multi-Scale Ecological Network Connectivity-Taking the Guangdong-Hong Kong-Macao Greater Bay Area as a Case Study.

The Guangdong-Hong Kong-Macao Greater Bay Area urban agglomeration is an urban agglomeration with some of the most intensive urbanization since 1980s. A large amount of cultivated land, forest land, water bodies and other land types in the region has been occupied by construction land, resulting in fragmented ecological landscapes and biodiversity in the region and causing many other ecological problems. Based on this, this paper takes the Guangdong-Hong Kong-Macao Greater Bay Area as a case study, constructs an ecological network of the dispersion scale of five species from 1990 to 2020 based on a morphological spatial pattern analysis (MSPA) method, identifies the ecological groups in the network and uses the core node-based community evolution path tracking algorithm to analyze the ecological groups in order to explore the changes of ecological network connectivity at different scales in the region and to reveal the overall and local characteristics and changes of the migratory space of terrestrial mammals with different dispersion capabilities. The research results show that: (1) From 1990 to 2020, the area of construction land in the Guangdong-Hong Kong-Macao Greater Bay Area increased sharply, with good connectivity in the northwest, southwest and eastern regions and poor connectivity in the central region. (2) There are obvious differences between the overall and local changes in the connectivity trends of multi-scale regional ecological networks. On the whole, the overall ecological connectivity of the ecological network at each scale showed a gradual upward trend, and the overall connectivity index IIC and the possible connectivity index PC gradually increased with the increase of the maximum dispersal distance of species. From the perspective of local patches, the larger the species dispersion scale, the larger the value of the revised betweenness centrality index and the patch possible connectivity index. (3) The distribution of ecological groups at different species dispersion scales is different, and the smaller the dispersal scale of the species, the greater the distribution of ecological groups. Small-scale species are limited by the maximum dispersal distance, and the range of their ecological groups is generally small. Small-scale (3 km), mesoscale (10 km) and large-scale (30 km) core nodes of ecological groups show a gradual increase trend, and the overall connectivity of ecological groups has improved. However, the core nodes of the extra-large-scale (60 km) and ultra-large-scale (100 km) ecological groups show a trend of decreasing fluctuations, and the overall connectivity within the ecological group has declined. This study is helpful to clarify the structural characteristics of regional ecological space and provide a theoretical basis for regional ecological planning.

Influences of Land Policy on Urban Ecological Corridors Governance: A Case Study from Shanghai.

The analysis of land use change (LUC) characteristics and the impact of policies related to urban ecological space is required to improve spatial planning and to support decision making regarding green infrastructure (GI) investment. This study employed Geo-informatic Tupu analysis and Fluctuation Potential Tupu analysis methods to analyze the characteristics of LUC in an urban ecological corridor (EC). To help understand the influence of land use policy on GI governance and support the optimization of spatial planning, we proposed a situation–structure–implementation–outcome (SSIO) policy cascade analysis framework. SSIO takes “place” as its starting point, then couples the local policy with the governance structure to promote the sustainability of urban commons governance. The results show that the land use type within an EC in the city is mainly cultivated land. However, between 2009 and 2019, cultivated land, construction land, and facility agricultural land all showed a decreasing trend, while forest land and garden land types underwent increasing trends. The LUC Tupu unit highlights the transition from cultivated land to forest land. Forest land has the greatest increase in area and accounts for 52.34% of the area of increasing land use. Cultivated land shows the greatest decrease in area and accounts for 70.30% of the area of decreasing trends. Based on the local policy situation of the metropolis, a land policy governance mechanism can be constructed by the establishment of a governance structure with local government as the core, using land consolidation as the platform, taking ecological spatial planning and inefficient construction land reduction as typical policy tools, and experimentally integrating the concept of Nature-based Solutions (NbS). In general, these findings may be applicable to other rapidly urbanizing cities around the world that are developing complex land use policies for ecological space governance.

Remote Sensing Land Use Evolution in Earthquake-Stricken Regions of Wenchuan County, China

Earthquakes and their secondary geological disasters have a certain impact on the land cover, which leads to the degradation of the ecological environment and the stability of the ecosystem. At present, there are few studies on the spatial–temporal evolution characteristics of land-use change in earthquake-stricken regions, especially the lack of quantitative evaluation of the impact of earthquakes on land use at the micro-scale. The “5·12” Wenchuan ms8.0 earthquake caused serious damage to the surface resources in the disaster area. The study on the spatial–temporal evolution characteristics of land-use change in the disaster area can provide a reference for the remote sensing dynamic monitoring of the ecological environment. Therefore, based on geographical big data, this paper used a land-use comprehensive degree index, land-use transfer matrix, and landscape ecological index to explore and analyze the spatial–temporal evolution characteristics of land use in Wenchuan County before and after the earthquake. The results showed that the types of cropland, forest, built-up, and bare land changed greatly before and after the earthquake. During the earthquake recovery period, the comprehensive index of land use in the study area basically showed an increasing trend. Under the effect of artificial measures and natural restoration, land use was continuously improved, and vegetation was restored well. After 2008, the Patch Density (PD) and Landscape Shape Index (LSI) values of most landscape types decreased, and the Aggregation Index (AI) values increased, indicating that the ecological environment of the whole region showed a benign development in the post-earthquake period. The results not only contribute to the establishment of scientific ecological environment management in earthquake-stricken regions but also contribute to the formulation of long-term ecological environment monitoring and ecological restoration planning according to the law of land-use change.

Land Cover Changing Pattern in Pre- and Post-Earthquake Affected Area from Remote Sensing Data: A Case of Lushan County, Sichuan Province

Extremely hard-hit areas face frequent secondary geological hazards and difficulties in vegetation recovery, and subsequent effects have a significant impact on land cover changes. At present, there is a lack of research on the dynamic restoration of, and changes in, the ecological environment before and after an earthquake, and especially a lack of quantitative assessment of the impact of earthquakes on land cover at the microscopic scale of spatial distribution of landscape indices. Taking the Lushan earthquake in Sichuan Province as an example, this paper obtained land cover data from the study area between 2012 and 2020, and analyzes the spatial distribution characteristics and influencing factors of land cover change frequency by using a comprehensive land cover degree index, land cover transfer matrix and landscape ecology index. The results show that the types of cropland, forest, built-up and bare land have changed significantly in the study area. During the earthquake recovery period, the comprehensive land cover index of the study area showed an increasing trend, and land cover has been continuously improved under the effect of artificial measures and natural restoration. After 2013, patch density (PD) and landscape shape index (LSI) values decreased and aggregation index (AI) values increased for the vast majority of landscape land classes, indicating a benign ecological development across the region in the post-earthquake period. The research results are not only helpful to establish scientific ecological environmental management in the earthquake-stricken areas, but also helpful to formulate medium- and long-term ecological environmental monitoring and ecological restoration plans based on land cover change patterns.

Analysis of the Influence of Forests on Landslides in the Bijie Area of Guizhou

Forests are an important part of the ecological environment, and changes in forests not only affect the ecological environment of the region but are also an important factor causing landslide disasters. In order to correctly evaluate the impact of forest cover on landslide susceptibility, in this paper, we build an evaluation model for the contribution of forests to the landslide susceptibility of different grades based on survey data for forest land change in Bijie City and landslide susceptibility data, and discuss the effects of forest land type, origin, age group, and dominant tree species on landslide susceptibility. We find that forests play a certain role in regulating landslide susceptibility: compared with woodland, the landslide protection ability of shrubland is stronger. Furthermore, natural forests have a greater inhibitory effect on landslides than artificial forests, and compared with young forest, mature forest and over-mature forest, middle-aged forest and near-mature forest have stronger landslide protection abilities. In addition, the dominant tree species in different regions have different impacts on landslides. Coniferous forests such as Chinese fir and Cryptomeria fortunei in Qixingguan and Dafang County have a low ability to prevent landslides. Moreover, the soft broad tree species found in Qianxi County, Zhijin County, Nayong County and Jinsha County are likely to cause landslides and deserve further research attention. Additionally, a greater focus should be placed on the landslide protection of walnut economic forests in Hezhang County and Weining County. Simultaneously, greater attention should be paid to the Cyclobalanopsis glauca tree species in Weining County because the area where this tree species is located is prone to landslides. Aiming at addressing the landslide susceptibility existing in different forests, we propose forest management strategies for the ecological prevention and control of landslides in Bijie City, which can be used as a reference for landslide susceptibility prevention and control.

Evaluation and analysis of water conservation function of ecosystem in Shaanxi Province in China based on "Grain for Green" Projects.

The evaluation of water conservation function of the ecosystem and the analysis of influencing factors are conducive to the implementation of "Grain for Green" Projects, scientific management of land use types, and the optimization of ecosystem service functions. In this paper, we selected the data of precipitation, soil, evapotranspiration, land use/cover change, and other data to quantitatively evaluate the water conservation function of the ecosystem in Shaanxi Province from 1980 to 2015 and explored the key factors which lead to the spatial differences in water conservation functions. The results showed that (1) from 1980 to 2015, the water production and water conservation of Shaanxi Province's ecosystem based on grid units decreased by 12.81 × 108 m3 and 7.74 × 108 m3, respectively. (2) The use types of cultivated land, forest land, and grassland had a prominent contribution to the water production and water conservation of the ecosystem, while the contribution rate of water area, construction land, and unused land was small. During the research period, "Grain for Green" Projects consumed a lot of water production in a short period of time, which was not conducive to the improvement of water production capacity in Shaanxi Province. However, the conversion of cultivated land to grassland would help improve the water conservation capacity of the ecosystem, increasing the water conservation capacity by 0.77 × 108 m3. (3) The water conservation function of Shaanxi Province was "hot in the south and cold in the north," with obvious regional and spatial heterogeneity from 1980 to 2015. (4) The factors of precipitation, evapotranspiration, slope, common cultivated land area, afforestation area, and water conservation function showed a positive correlation, and the impact was significant, while the overall vegetation coverage index showed a negative correlation with it. Therefore, it is necessary to comprehensively consider the local climatic and environmental conditions to implement ecological protection and restoration policies in terms of enhancing water conservation function of the ecosystem. (5) Targeted measures are proposed for different areas in Shaanxi Province: The Northern Shaanxi area should be regarded as an ecological restoration and management area, focusing on returning farmland to grassland; Central Shaanxi Plain should be considered as an ecological protection zone, and the key task is to effectively protect the ecological land; the Southern Shaanxi area should be regarded as a key water conservation area, and the main function of the forest and grass ecosystem to conserve water is to be exerted.

R-IMNet: Spatial-Temporal Evolution Analysis of Resource-Exhausted Urban Land Based on Residual-Intelligent Module Network

The transformation of resource-exhausted urban land is an urgent problem for sustainable urban development in the world today. Obtaining the urban land use type and analyzing the changes in their land use can lead to better management of the relationship between economic development and resource utilization. In this paper, a residual-intelligent module network was proposed to solve the problems of low classification accuracy and missing objects edge information in traditional computer classification methods. The classification of four Landsat-TM/OLI images from 1993–2020 for Jiaozuo city (the first batch of resource-exhausted cities in China) was realized by this method. The results (overall accuracy was 98.61%, in 2020 images) were better than the comparison models (support vector machine, 2D-convolutional neural network, hybrid convolution networks; overall accuracy was 87.12%, 96.16%, 98.46%, respectively) and effectively reduced the loss of information on the edge of the ground objects. On this basis, six main land use types were constructed by combining field surveys and other methods. The characteristics and driving forces of spatial-temporal change in land use were explored from the aspect of social, economic and policy factors. The results showed that from 1993 to 2020 the cultivated land, forest land, water body and other land types in the study area decreased by 690.97 km2, 57.54 km2, 47.04 km2 and 59.43 km2, respectively. The construction land and bare land increased by 839.38 km2 and 15.57 km2, respectively. The transfer of land use types was mainly from cultivated land to construction land, with a cumulative conversion of 920.95 km2 within 27 years. The driving forces of land use in the study area were analyzed by principal component analysis (PCA) and regression analysis. The spatial-temporal evolution of land use types was affected by policy changes, the level of social development and the adjustment in the economy, industry and agriculture structure. The investment in fixed assets and per capita net income in rural areas were the top two influencing factors and their cumulative contribution rate was 94.62%. The findings of this study can provide scientific reference and theoretical support for land use planning, land reclamation in mining areas, ecological protection and sustainable development in Jiaozuo and other resource-exhausted cities in the world.

Spatial Heterogeneity of PM2.5 Concentration in Response to Land Use/Cover Conversion in the Yangtze River Delta Region

The sustainable management direction of PM2.5 concentrations in the Yangtze River Delta region remains unclear due to regional spatial effects. This study combined the random forest model, spatial econometric model, and multi-scale geographically weighted regression model (MGWR) to explore the multi-scale spatial response of PM2.5 concentration to land use/cover conversion. The results show that:① PM2.5 concentrations in the Yangtze River Delta region from 2000 to 2018 showed four types of spatial-temporal patterns of spatially continuous aggregation, with strong regional synchronous changes. ② The relative influence of land conversion on PM2.5 concentrations showed a complex performance, and the source-sink effect of cultivated land and forest land was obvious. Neighborhood analysis indicated that the effect of surrounding aggregated land use conversion was generally more significant than that of single cells on PM2.5 concentration change, and the spatial effect was obvious. ③ PM2.5 concentration changes were mostly significantly negatively correlated with forest land and grassland conversion types and significantly positively correlated with conversion types between cropland, construction land, and water bodies. The importance ranking of the random forest model and correlation coefficient intensity indicated that the conversion between cropland-cropland (29.65%; 0.650), forest land-forest land (26.98%; 0.726), construction land-cropland (22.57%; 0.519), cropland-forestland (17.84%; 0.602), and cropland-construction land (16.34%; 0.424) contributed more to the variation in PM2.5 concentration. The spatial Durbin model revealed a significant spatial dependence of the change in PM2.5 concentration and a strong spatial spillover effect. ④ The MGWR model revealed the scale effects and non-stationary characteristics of the spatial relationships between different land use conversions acting on PM2.5 concentration change, and its spatial relationship showed strong differences in transfer types. However, the multi-models revealed that different land conversions drove the PM2.5 concentration change in different ways, so it is necessary to formulate targeted joint management strategies in a categorical and hierarchical manner.

Soil gross nitrogen transformations in forestland and cropland of Regosols

Soil gross nitrogen (N) transformations could be influenced by land use change, however, the differences in inherent N transformations between different land use soils are still not well understood under subtropical conditions. In this study, an 15N tracing experiment was applied to determine the influence of land uses on gross N transformations in Regosols, widely distributed soils in Southwest China. Soil samples were taken from the dominant land use types of forestland and cropland. In the cropland soils, the gross autotrophic nitrification rates (mean 14.54 ± 1.66 mg N kg−1 day−1) were significantly higher, while the gross NH4+ immobilization rates (mean 0.34 ± 0.10 mg N kg−1 day−1) were significantly lower than those in the forestland soils (mean 1.99 ± 0.56 and 6.67 ± 0.74 mg N kg−1 day−1, respectively). The gross NO3− immobilization and dissimilatory NO3− reduction to NH4+ (DNRA) rates were not significantly different between the forestland and cropland soils. In comparison to the forestland soils (mean 0.51 ± 0.24), the cropland soils had significantly lower NO3− retention capacities (mean 0.01 ± 0.01), indicating that the potential N losses in the cropland soils were higher. The correlation analysis demonstrated that soil gross autotrophic nitrification rate was negatively and gross NH4+ immobilization rate was positively related to the SOC content and C/N ratio. Therefore, effective measures should be taken to increase soil SOC content and C/N ratio to enhance soil N immobilization ability and NO3− retention capacity and thus reduce NO3− losses from the Regosols.

Quantifying the Spatial Heterogeneity and Driving Factors of Aboveground Forest Biomass in the Urban Area of Xi’an, China

Investigating the spatial distribution of urban forest biomass and its potential influencing factors would provide useful insights for configuring urban greenspace. Although China is experiencing an unprecedented scale of urbanization, the spatial pattern of the urban forest biomass distribution as a critical component in the urban landscape has not been fully examined. Using the geographic detector method, this research examines the impacts of four geographical factors (GFs)—dominant tree species, forest categories, land types, and age groups—on the aboveground biomass distribution of urban forests in 1480 plots in Xi’an, China. The results indicate that (1) the aboveground biomass and four GFs show obvious heterogeneity regarding their spatial distribution in Xi’an; (2) the dominant tree species and age group which impacts the patterns of aboveground biomass are the primary GFs, with the independent q value (a statistic metric used to quantify the impacts of GFs in this study) reaching 0.595 and 0.202, respectively, while the forest category and land type were weakly linked to the spatial variation of aboveground biomass, with a q value of 0.087 and 0.076, respectively; and (3) the interactions among these four GFs also tend to contribute to the distribution pattern of aboveground biomass. The interactions between GFs achieved a larger impact than the sum of impacts that were independently obtained from the factors. Our results showed that the method of using a geographical detector is a useful tool in the urban area, and can reveal the driver pattern of aboveground biomass and provide a reference for city planning and management.

Forestland landscape change induced spatiotemporal dynamics of subtropical urban forest ecosystem services value in forested region of China: A case of Hangzhou city

Understanding of urban forestland both type structure and change and their effects on forest ecosystem services (ES) is important for maintaining and enhancing the quality of life as well as ensuring sustainable urban planning in cities. In Hangzhou city of Zhejiang province in Southeast China, forestland covers more than 71% of its total land area, thereby providing a high variety of ES. Many studies have focused on the effects of land use change on ES value (ESV), but these have only applied to the first-level classification of land use. So there is an urgent need for studies to measure the effects of land use change on ESV applied to the second-level classification of land use. In this present study, from a rare insight into the forestland landscape change of Hangzhou city, the spatiotemporal dynamics of urban forest ESV (UFESV) during the period of 2000–2015 are analyzed based on the combination of remote sensing and a light-use-efficiency model (CASA). The results indicate that the total value of urban forest ES increases from 9.79 × 108 Yuan in 2000 to 12.31 × 108 Yuan in 2015, with a net increase of 2.52 × 108 Yuan in Hangzhou city, and forested land has the highest UFESV, contributing about 99.49% of the total services value, although the area of forestland decreases by 101.99 km2 over the past 15 years. Carbon fixation and oxygen release and organic matter production are the two dominant service functions, accounting for 87.56% of the total on average. The construction and planning of Hangzhou's forest city has a positive impact on the value of urban forest ES during 2000–2015.