Conversion Of Forest Land Research Articles

城市化对流域生态水文过程的影响研究综述

了解流域水文过程（水量和水质）是流域综合管理的基础。城市化引起的生态环境问题已成为目前和未来一段相当长的时期内人类社会面临的重大问题。然而，城市化（土地利用/覆被变化、新污染物产生）、水文（降水、入渗、蒸散、径流过程）和生态系统服务（产水服务、调节气候、土壤保持、初级生产力、维持生物多样性等）在不同时空尺度之间的相互作用还存在知识空白。从城市化对流域生态系统结构和功能的影响、城市化对地表能量平衡与水量平衡的影响、城市化对水质和水生生物的影响、以及城市土地利用/覆被变化的大气环境效应等多方面系统总结了城市化影响流域生态水文过程的研究进展。研究发现，城市"热岛"、"干岛"、暴雨径流引起的城市内涝、水污染等环境现象都与生态水文过程密切相关。强调现代城市规划需要遵循生态水文学规律，从全流域生态系统角度认识近年来新出现的不同尺度的城市环境效应。城市最佳管理措施应以流域为单元实施，以调节土地利用/覆被、保护湿地（包括自然与人工湿地）为手段，充分发挥自然生态系统调节功能（如植被蒸散和净化水质）。未来城市生态水文学应围绕"低影响开发"以及"基于自然的解决方案"等城市流域管理措施，在稳定城市小气候、缓解洪涝干旱等极端水文气象灾害风险以及减轻城市水污染等方面开展多尺度综合研究。;Ecohydrology is the most basic science for guiding integrated watershed management. Rapid urbanization permanently alters land cover and the structure and functions of terrestrial ecosystems in a short period of time. Consequently, urbanization affects hydrological processes such as surface evaporation, runoff, and local and regional climate, and ecosystem services (e.g., water supply, carbon sequestration, biodiversity). Urbanization directly affects the physical properties of the near-surface atmosphere, the energy exchange between land and atmosphere, and the water budget of the ecosystems. These changes bring or aggravate a series of water quantity, water quality, and climatic effects, e.g., heat island, dry island, wet island, rain island, and turbid island. This study systematically summarized the research progress in understanding the impacts of urbanization on watershed ecohydrological processes with a focus on the consequences of urbanization on surface energy balance, water balance, water quality and aquatic organisms, and the meteorological effects of urban land use/cover change. The most direct impact of urban land use/cover change on the environment is the alternation of the energy and water balance at multiple scales. The unique physical properties of the urban surface and associated energy balance distribution characteristics are different from natural ecosystems, resulting in unique microclimate and eco-hydrology in an urban environment. Urbanization-driven surface processes have direct or indirect impacts on hydrological processes such as runoff, infiltration, evapotranspiration, groundwater recharge, and river network confluence at different scales by increasing impervious surface and changing vegetation cover conditions. Large-scale urbanization aggravates the peak flow, rainstorm runoff, and annual total water yield as a result of evapotranspiration reduction caused by the significant reduction of vegetation and surface soil infiltration rate. The influence of urbanization on non-point source water pollution is mainly reflected in the change of ‘source’, ‘process’, and ‘sink’ of non-point source pollutants. Urbanization aggravates water quality problems by the increase in impervious surface that elevates pollutant concentration and load and alters physical and chemical processes in aquatic systems. Large-scale conversion of forest lands to urban uses leads to a significant reduction in evapotranspiration, which reduces its ‘biological drainage’ function, coupled with an increase in the impervious surface, and is likely to exacerbate the risk of flooding or the risk of ‘light rainstorms, heavy waterlogging’ phenomena in urban watersheds. The conversions of vegetated ecosystems reduce their ‘air conditioner’ functions and are likely to exacerbate the ‘urban heat island’ and ‘urban dry island’ effects. We summarized measures and strategies centered on ‘Low Impact Development’ to mitigate the urbanization risks through reducing extreme hydrological effects of impervious surface, enhancing the regulating function of natural ecosystems, and implementing the Urban Best Management Practices at a watershed scale. We concluded that future urban ecohydrological science should focus on the studying the mechanisms of ‘Low Impact Development’ and ‘Nature-based Solutions’ in mitigating environmental impacts from the perspectives of water and energy balances and biogeochemical cycling at multiple scales.

Delineate Soil Characteristics and Carbon Pools in Grassland Compared to Native Forestland of India: A Meta-Analysis

Grassland is a highly dynamic land use system and it provides vital ecosystem services, mainly consisting of carbon storage in the tropics and subtropics. The objective of this study was to delineate grassland in India according to soil characteristics and carbon pools in comparison to native forestland, and to discuss management strategies for improving soil carbon (SC) storage in grassland. A total of 675 paired datasets from studies on grassland and forestland in India generated during the period of 1990–2019 were used for meta-analysis study. The analysis shows that soil pH and bulk density (BD) in grasslands were greater by 1.1% and 1.0% compared to forestlands while soil organic carbon (SOC) declined by 36.3% (p < 0.05). Among carbon pools, labile carbon (LC), non-labile carbon (NLC), and microbial biomass carbon (MBC) were 35.5%, 35.3% and 29.5% lower, respectively, in the grassland compared to the forestland. Total carbon (TC) was 35.0% lower in the grassland than the forestland (p < 0.05). Soil carbon stocks (SCS) were 32.8% lower in the grassland compared to the forestland. In the grassland, MBC/SOC (%) from the surface layer and subsurface layer were lower by 2.4% and 8.5%, respectively compared to forestland. The percentage effect size was found to have decreased from surface soil to subsurface soil. Relative SCS loss and carbon dioxide equivalent emission from the grassland compared to forestland were 15.2% and 33.3 Mg ha−1, respectively (p < 0.05). Proper management strategies like agroforestry, legume introduction, silvipastoral system, fertilization, irrigation, and quality grass species could improve SC storage and reduce SCS loss in grassland. Overall, this study gives an idea that conversion of native forestland into grassland in India has declined the SC content and hence it is necessary to adapt proper strategies to manage the soil-atmosphere carbon balance.

Spatio-Temporal Evolution of Land Use Transition and Its Eco-Environmental Effects: A Case Study of the Yellow River Basin, China

Human activities and environmental deterioration have resulted in land use transition (LUT), which seriously affects the ecosystem service value (ESV) of its region. Therefore, relevant policy measures are urgently needed. Nevertheless, research on the relationships between LUTs and ESVs from the overall watershed scale is lacking. Thus, the geo-information Tupu method was applied to analyze the dynamic patterns of LUT based on land use data from 1990, 2000, 2010, and 2018 of the Yellow River Basin (YRB). Then, a newly revised ecosystem services calculation method was utilized to the responses of ESV to LUTs. The results indicated that the Tupu units of the LUT were mainly based on the mutual transformation of grassland and unused land, and cultivated land and forestland, which were widely distributed in the upper and middle reaches of the basin. The spatial distribution was concentrated, and the expansion’s trend was also obvious. Moreover, the conversion of cultivated land into construction land was mainly distributed in the lower reaches of the basin. During 1990–2018, the total ESV fluctuated and increased (+10.47 × 108 USD) in the YRB. Thereinto, the ESV of grassland (45%) and forestland (30%) made the greatest contribution to the total ESV. As for different reaches, the ESV increased in the upstream, but decreased in the midstream and the downstream. In terms of contribution rate, the conversion of unused land into grassland (12.477%) and grassland into forestland (9.856%) were the main types to enhance the ESV in the YRB, while the conversion of forestland into grassland (−8.047%) and grassland to unused land (−7.358%) were the main types to reduce the ESV. Furthermore, the range of ecological appreciation zones was widely distributed and scattered, while the range of ecological impairment zones was gradually expanded. These findings could have theoretical support and policy implications for land use planning and environmental services in the YRB.

ANALISIS PERUBAHAN LUAS HUTAN MANGROVE DAN FAKTOR YANG MEMPENGARUHINYA DI PULAU TANAKEKE KAB. TAKALAR

Knowing how the changes in the area of mangrove forest on Tanakeke Island, Takalar Regency in 1998 - 2018, Knowing the factors that influence changes in the area of mangrove forests on Tanakeke Island, Takalar Regency.Analysis of changes used is remote sensing image analysis. The imagery used is LANDSAT 5 TM satellite imagery acquisition in 1998, LANDSAT 7 + ETM satellite imagery acquisition in 2008 and LANDSAT 8 imagery OLI acquisition in 2018. Guided classification method with maximum like-lihood method is used to determine changes in mangrove forest area, while for activity factors humans that affect changes in mangrove area are analyzed in terms of percentage descriptions. The area of Tanakeke Island's mangrove forests in 1998 was 3,309.93 hectares, in 2008 it was 2,699.2 hectares, which was reduced by 621.91 hectares. And in 2018 the area will be 2,421.38 hectares and the total change in the area of mangove forests will be reduced by 908.55 hectares. The factors of human activity that affect changes in the area of mangrove forests most importantly is the conversion of mangrove forest land into ponds and uncontrolled collection of firewood for firewood.

How Tillage and Fertilization Influence Soil N2O Emissions after Forestland Conversion to Cropland

Soil nitrous oxide (N2O) emissions are influenced by land use adjustment and management practices. To meet the increasing socioeconomic development and sustainable demands for food supply, forestland conversion to cropland occurs around the world. However, the effects of forestland conversion to cropland as well as of tillage and fertilization practices on soil N2O emissions are still not well understood, especially in subtropical regions. Therefore, field experiments were carried out to continuously monitor soil N2O emissions after the conversion of forestland to cropland in a subtropical region in Southwest China. One forestland site and four cropland sites were selected: forestland (CK), short-term croplands (tillage with and without fertilization, NC-TF and NC-T), and long-term croplands (tillage with and without fertilization, LC-TF and LC-T). The annual cumulative N2O flux was 0.21 kg N ha−1 yr−1 in forestland. After forestland conversion to cropland, the annual cumulative N2O flux significantly increased by 76‒491%. In the short-term and long-term croplands, tillage with fertilization induced cumulative soil N2O emissions that were 94% and 235% higher than those from tillage without fertilization. Fertilization contributed 63% and 84% to increased N2O emissions in the short-term and long-term croplands, respectively. A stepwise regression analysis showed that soil N2O emissions from croplands were mainly influenced by soil NO3− and NH4+ availability and WFPS (water-filled pore space). Fertilization led to higher soil NH4+ and NO3− concentrations, which thus resulted in larger N2O fluxes. Thus, to reduce soil N2O emissions and promote the sustainable development of the eco-environment, we recommend limiting the conversion of forestland to cropland, and meanwhile intensifying the shift from grain to green or applying advanced agricultural management practices as much as possible.

Impacts of Climate and Land-Use Change on Blue and Green Water: A Case Study of the Upper Ganjiang River Basin, China

Quantitatively figuring out the effects of climate and land-use change on water resources and their components is essential for water resource management. This study investigates the effects of climate and land-use change on blue and green water and their components in the upper Ganjiang River basin from the 1980s to the 2010s by comparing the simulated changes in blue and green water resources by using a Soil and Water Assessment Tool (SWAT) model forced by five climate and land-use scenarios. The results suggest that the blue water flow (BWF) decreased by 86.03 mm year−1, while green water flow (GWF) and green water storage (GWS) increased by 8.61 mm year−1 and 12.51 mm year−1, respectively. The spatial distribution of blue and green water was impacted by climate, wind direction, topography, and elevation. Climate change was the main factor affecting blue and green water resources in the basin; land-use change had strong effects only locally. Precipitation changes significantly amplified the BWF changes. The proportion of surface runoff in BWF was positively correlated with precipitation changes; lateral flow showed the opposite tendency. Higher temperatures resulted in increased GWF and decreased BWF, both of which were most sensitive to temperature increases up to 1 °C. All agricultural land and forestland conversion scenarios resulted in decreased BWF and increased GWF in the watershed. GWS was less affected by climate and land-use change than GWF and BWF, and the trends in GWS were not significant. The study provides a reference for blue and green water resource management in humid areas.

Palm Oil and the Politics of Deforestation in Indonesia

This paper studies the interactions between political and economic incentives to foster forest conversion in Indonesian districts. Using a district–level panel data set from 2001 to 2016, we analyze variation in remotely sensed forest losses as well as measures of land-use licensing. We link these outcomes to political incentives arising before idiosyncratically–timed local mayoral elections as well as to price exposure measures based on oil palm soil suitability combined with global price variations for palm oil. Empirical results document increases of about 4% in deforestation in the year prior to local mayoral elections on average. Additionally, palm oil plays a crucial role in driving deforestation dynamics. Deforestation rates increase by 7% in places that experience a one standard deviation increase in local price exposure, but no upcoming elections. These effects are amplified to almost 19% larger forest losses in places that experience pre-election years and a standard deviation higher palm oil price exposure at the same time. We thus find clear evidence for economic and political incentives reinforcing each other as drivers of forest loss and land conversion for oil palm cultivation.

Land use change and driving factors in rural China during the period 1995-2015

Land use/cover change (LUCC) is the result of interaction between human activities and biophysical processes. Extensive researches have been done on LUCC in urban China, but the understanding on rural land-use remains relatively inadequate. Based on land use, socio-economic, topographic and climate data from 1995–2015, taking China’s 31,275 townships as the research object, this study applied land-use dynamic degree (LUDD), geo-detector model and bivariate spatial autocorrelation analysis to explore the spatio-temporal pattern and driving factors of LUCC in rural China. Results show that over the past two decades, significant changes have taken place in the type and structure of land use in rural China. The cultivated land increased in northeast and northwest China, and the built-up area increased in Yangtze River Delta, Pearl River Delta and Beijing-Tianjin-Hebei region as well as Henan and Anhui provinces. More than 80 % of built-up land expansion came from the occupation of cultivated land. The Loess Plateau, Sichuan Basin, Hebei, Henan, western Xinjiang and southern Jiangsu have experienced the most serious decline in arable land. The driving force of LUCC varied greatly with space, time and land use type. Socio-economic development was the main driving force for the built area expansion, and geographical differentiation was the dominant factor in the conversion of cultivated land, forest land and grassland. The intensity of population and economic growth driving built-up land expansion decreases from east to west, while that of terrain-driven conversion of cultivated land into forest land gradually increases from west to east. These findings would provide decision support for policy-makers to formulation future sustainable land use policies. At the same time, it would help to further promote the exploration of China’s complicated human-land relationship.

Regional variations in life cycle greenhouse gas emissions of canola‐derived jet fuel produced in western Canada

AbstractThis study investigates the life cycle GHG emissions of jet fuel produced via the hydroprocessed esters and fatty acids (HEFA) pathway from canola grown in western Canada, with a focus on characterizing regional influences on emissions. We examine the effects of geographic variations in soil type, agricultural inputs, farming practices, and direct land use changes on life cycle GHG emissions. We utilize GREET 2016 but replace default feedstock production inputs with geographically representative data for canola production across eight western Canadian regions (representing 99% of Canada's canola production) and replace the default conversion process with data from a novel process model previously developed in ASPEN in our research group wherein oil extraction is integrated with the HEFA‐based fuel production process. Although canola production inputs and yields vary across the regions, resulting life cycle GHG emissions are similar if effects of land use and land management changes (LMC) are not included; 44–48 g CO2e/MJ for the eight regions (45%–50% reduction compared to petroleum jet fuel). Results are considerably more variable, 16–58 g CO2e/MJ, when including effects of land use and LMC directly related to conversion of lands from other uses to canola production (34%–82% reduction compared to petroleum jet fuel). We establish the main sources of emissions in the life cycle of canola jet fuel (N‐fertilizer and related emissions, fuel production), identify that substantially higher emissions may occur when using feedstock sourced from regions where conversion of forested land to cropland had occurred, and identify benefits of less intense tillage practices and increased use of summerfallow land. The methods and findings are relevant in jurisdictions internationally that are incorporating GHG emissions reductions from aviation fuels in a low carbon fuel market or legislating carbon intensity reduction requirements.

Policy forum: Reconciling palm oil targets and reduced deforestation: Landswap and agrarian reform in Indonesia

Palm oil is very important exported commodity in Indonesia, which currently generates more than USD18 billion to the national earnings. Oil palm (Elaeis guineensis, Jacq.) is the most efficient crop in terms of productivity in producing oil compared with other crops, such as soybean, rapeseed and sunflower. Indonesia is a major palm oil producer in the world, where the oil palm plantation covers more than 14 million hectare of lands. The Government of Indonesia (GoI) has set a target to increase its palm oil production from 25 million tons in 2010 to 50 million tons by 2020. While the total palm oil production in 2019 is about 40 million tons, then it needs 10 million tons more palm oil production to achieve the target in 2020. Consequently, further forestland conversion maybe required to establish new oil palm plantations. This study proposes a scenario to swap forest lands with non-forests or low carbon lands in Central Kalimantan. The scenario will be successfully implemented through the presence of incentives to participate, appropriate policies, and facilitative government. Agrarian reform is a facilitative top down policy of landuse and land distribution has to be implemented by local government. This study concludes that integration of landswap proposal into agrarian reform, so called adjusted landuse scenario is relevant to the evidence-based policy that will provide local government with a strong institutional basis, simplifying process, and significant cost efficiency to perform land swap procedures. This policy has a great potential to reconcile growth of the oil palm plantation and reducing deforestation.

The conversion of forestland into agricultural land without appropriate measures to conserve SOM leads to the degradation of physical and rheological soil properties

This study was conducted to compare soil particle density (ρs), soil total porosity (TP), liquid limit (LL), plastic limit (PL), and plasticity index, and their relations with soil organic matter (SOM), of non-carbonate silty clay Fluvisols under different land uses. Three neighboring land uses were studied: native deciduous forest, arable land, and meadow, managed in the same way for more than 100 years. Soil was collected from 27 soil profiles and from three depths (0–15, 15–30 and 30–45 cm). Land use caused statistically significant but different impacts on soil properties, particularly in the topsoil. The forest topsoil measured the lowest ρs and bulk density (ρb) but the highest SOM and soil water content at PL, compared to meadow and arable soil. Statistically significant linear relationship was observed with the SOM content and ρs (− 0.851**), ρb (− 0.567**), calculated TP (0.567**) and measured TP (− 0.280**). There was a nonlinear relationship between SOM and LL (0.704**) and PL (0.845**) at the topsoil. The findings suggested that SOM content strongly affected ρs, ρb, TP, LL and LP. This regional study showed that the conversion of forestland into agricultural land without appropriate measures to conserve SOM leads to the degradation of physical and rheological soil properties.

Impact of conventional agriculture on the concentration and quality of water-extractable organic matter (WEOM) in the surface horizons of Retisols—A case study from the Carpathian Foothills in Poland

In spite of many studies focused on the impact of land use changes on soil organic carbon (SOC) and the total nitrogen (TN) and soil organic matter (SOM) budget, less is known about the fate of water-extractable organic matter (WEOM) after the conversion of forestland to conventional farmland. The main aims of this study were: 1) to determine the concentration of water-extractable organic carbon (WEOC) and water-extractable total nitrogen (WETN) in topsoil horizons of forestland soils and cropland soils in the Carpathian Foothills in southern Poland and 2) to determine the quality of WEOM in topsoil horizons of forestland soils and cropland soils. Soil samples from topsoil horizons of forestland soils (Oi and Ah horizons) and cropland soils (Ap horizons) were collected and the concentration of WEOC and WETN was determined. In addition, the quality of WEOM was determined using ultraviolet-visible (UV–vis) spectroscopy and Fourier-transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy. The results of this comparative study clearly indicate that conventional agriculture significantly affects the concentration and quality of WEOM in surface soil horizons of Retisols in the Carpathian Foothills in southern Poland. Surface horizons of arable soils (Ap horizons) are characterized by a significantly lower mean concentration of WEOC and WETN in comparison with surface horizons of forestland soils (Oi and Ah horizons), and reflect changes in the content of bulk SOC and TN due to soil tillage. Mean concentrations of WEOC and WETN in the studied Ap horizons of arable soils are 1.98 mg l−1 and 0.15 mg l−1, respectively while the mean concentrations of WEOC and WETN in the Ah horizons of forestland soils are 15.53 mg l−1 and 0.84 mg l−1, respectively. The studied Oi horizons of forestland soils are characterized by the highest mean concentration of WEOC (44.53 mg l−1) and WETN (6.22 mg l−1). Mean specific UV absorbance values at wavelength of 254 nm (SUVA254) was the highest for WEOM from Ap horizons indicating the highest transformation of WEOM in these horizons. Mean FTIR-ATR absorption bands of WEOM obtained from Oi and Ah horizons are much more intensive than the bands of WEOM from Ap horizons, which is related to significantly lower concentration of WEOM in the latter horizons in comparison with Oi and Ah horizons of forestland soils.

Identification of Short-Rotation Eucalyptus Plantation at Large Scale Using Multi-Satellite Imageries and Cloud Computing Platform

A new method to identify short-rotation eucalyptus plantations by exploring both the changing pattern of vegetation indices due to tree crop rotation and spectral characteristics of eucalyptus in the red-edge region is presented. It can be adopted to produce eucalyptus maps of high spatial resolution (30 m) at large scales, with the use of open remote sensing images from Landsat 8 Operational Land Imager (OLI), MODerate resolution Imaging Spectroradiometer (MODIS), and Sentinel-2 MultiSpectral Instrument (MSI), as well as a free cloud computing platform, Google Earth Engine (GEE). The method is composed of three main steps. First, a time series of Enhanced Vegetation Index (EVI) is constructed from Landsat data for each pixel, and a statistical hypothesis testing is followed to determine whether the pixel belongs to a tree plantation or not based on the idea that tree crops should be harvested in a specific period. Then, a broadleaf/needleleaf classification is applied to distinguish eucalyptus from coniferous trees such as pine and fir using the red-edge bands of Sentinel-2 data. Refinements based on superpixel are performed at last to remove the salt-and-pepper effects resulted from per-pixel detection. The proposed method allows gaps in the time series that are very common in tropical and subtropical regions by employing time series segmentation and statistical hypothesis testing, and could capture forest disturbances such as conversion of natural forest or agricultural lands to eucalyptus plantations emerged in recent years by using a short observing time. The experiment in Guangxi province of China demonstrated that the method had an overall accuracy of 87.97%, with producer’s accuracy of 63.85% and user’s accuracy of 66.89% for eucalyptus plantations.

Assessment of LULC Change and Its Impact on Soil Erosion Using GIS and Revised Universal Soil Loss Equation Model

Land use is one of the vital factors in estimating soil erosion over an area. Significant changes in spatio-temporal land use distribution might lead to water runoff which causes soil erosion events. It is important to assess the soil erosion risk for hydropower reservoir as part of sediment management activities. This study aims to assess the impact of land use and land cover (LULC) changes on soil erosion risk at Chenderoh catchment in Perak. LULC distribution within the study area was mapped for 2008, 2010 and 2015 by using land use maps obtained from Department of Agriculture, Malaysia. The soil loss rate was measured using the Revised Universal Soil Loss Equation (RUSLE) utilizing spatial data of rainfall factor, soil erodibility, topographical factor, conservation factor, and support practice factor. Average soil loss was calculated according to sub-catchment of Chenderoh, and it is found that the soil loss trend marginally increases from year 2008 to 2015. Based on soil erosion risk map results, it is found that conversion of forest land to agriculture is the main contributor to soil loss, which might be due to land clearance and agriculture practice activities.

Impact of agriculture on soil organic matter quantity and quality in Retisols – a case study from the Carpathian Foothills in Poland

ABSTRACT Changes in land use are very important factors affecting soil quality and especially the concentration and stock of soil organic carbon (SOC) and total nitrogen (TN). Very little is known about changes in spectroscopic properties of SOM after conversion of forestland to cropland. Therefore, the main aim of this study was to determine impact of agriculture on the concentration and stock of SOC and TN as well as spectroscopic properties of SOM in the topsoil horizons of Retisols in the Carpathian Foothills in southern Poland. Topsoil Ap horizons of arable soils are characterized by a significantly lower concentration of SOC and TN in comparison with topsoil Oi and Ah horizons of forestland soils. Topsoil Ap horizons feature higher SOC and TN stocks than topsoil Oi and Ah horizons. Significantly higher concentrations of SOC and TN in Oi horizons in comparison with Ah and Ap horizons are responsible for significantly higher mean absorbance values of all FTIR-ATR absorption bands originating from SOM in Oi horizons versus Ah and Ap horizons. Significantly higher concentrations of SOC and TN in Ah horizons of forestland soils versus those in Ap horizons of arable soils do not significantly affect mean absorbance values of FTIR-ATR bands.

Distribusi Nepenthes spp. di Hutan Kalampangan

Kalampangan peat swamp forests in Central Kalimantan is home for Nepenthes spp. However, the number of Nephentes has been reduced due to massive forest fires and land conversion for housing and agricultural purposes. Nepenthes is a unique plant with ability to prey insects, hence often referred to as 'insectivorous plant'. This study investigates the distribution of Nepenthes spp. in Kalampangan forest through ground check and qualitative descriptive approach. A total of six observation plots measuring of 2m x 2m were used purposively. The results show there are four Nepenthes species found, namely Nepenthes gracilis, Nepenthes mirabilis, Nepenthes gracilis cortis, and Nepenthes ampularia. The highest Morisita index is 1.06 while the lowest one is 1.01.

Review of life‐cycle greenhouse‐gas emissions assessments of hydroprocessed renewable fuel (HEFA) from oilseeds

AbstractRenewable fuel from the hydroprocessed esters and fatty acids (HEFA) pathway represents a promising short‐term option for reducing fossil fuel use in transportation. However, some life‐cycle assessments (LCAs) have shown that HEFA diesel and jet fuel may have higher life‐cycle greenhouse gas (GHG) emissions than the fossil fuels they replace. Many of these studies examined HEFA fuel derived from oilseed feedstocks. Here, results and methodology from 20 LCAs of HEFA fuel from oilseeds are reviewed in an effort to determine the sources of variability in the reported life‐cycle GHG emissions of HEFA fuels. Although there was a 61–63% reduction in median life cycle GHG emissions of HEFA biojet and renewable diesel compared to conventional petroleum fuels, this review highlights the importance of standardized methodologies for life‐cycle assessment (e.g., CORSIA, RSB) and indicates the need to prevent the conversion of forest land for biofuel production, as well as the potential opportunity for alternative oilseeds such as camelina and carinata as feedstocks to produce HEFA fuels with lower life‐cycle GHG emissions. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

Analysis of Spatial and Temporal Dynamics of Land Use Land Cover Change in Port Harcourt Areas of River State

It is estimated that by the year 2050, half of the world will be urbanized and developing countries will be leading the crusade. This rapid urbanization will put more pressure on environmental system. The traditional in-situ assessment of land change will no longer be feasible because of increased urbanization. This study assessed the land use/ land cover dynamics in Port Harcourt city of River State. Land-use classification and change detection was conducted using multiple satellite data sources (Landsat TM, ETM) of Port Harcourt city for 1986, 2003 and 2018. Kappa statistical too and ArcGIS Software were also employed for further analysis. The key findings showed that urbanization was rapid and exponential. These observed urbanization occurred due to conversion of forest reserves, agricultural lands and water bodies to urban land. Keywords: Land use, Land cover, Satellite, Imagery, Urbanization, Port Harcourt DOI: 10.7176/JEES/10-6-05 Publication date: June 30 th 2020

Soil organic carbon, its fractions and soil organic carbon stocks under different land use systems in Typic Ustrochrepts of northwest India

A study was conducted to assess the impact of different land use systems on soil organic carbon (SOC), its fractions and soil organic carbon stocks under different land use systems in a mixed watershed in the submontane region of north-west India. Soil samples were collected up to a depth of 120 cm from three locations each from maize-wheat, agro-horticulture and agroforestry (3 and 6-year plantation) land use systems. The results revealed that the surface soils (0–15 cm) under agroforestry had significantly higher SOC (5.3 mg g− 1) than in soils under other cropping systems and varied from 4.3 to 5.3 mg g− 1. The labile carbon (LC), aggregate associated carbon (AAC), particulate organic carbon (POC) and mineralizable carbon (MC) were also significantly higher in surface soils under agroforestry 6-year plantation than other three cropping systems and thereafter exhibited significantly lower content of SOC and its fractions in each of the depth as compared to the surface soil in all the cropping systems except maize-wheat system where LC increased significantly in the second depth and decreased gradually in the subsequent lower depths. The proportion of these fractions in relation to the soil organic carbon was lowest in soils under maize-wheat (10–70%) than the tree-based cropping systems (20–100%). The typical decrease of SOC content in the 3rd depth (30–60 cm) was the sharpest and thereafter it stabilized in lower depths in maize-wheat system. The SOC stock followed the trend: agroforestry 6-year (38 Mg ha− 1) > agroforestry 3-year (30.5 Mg ha− 1) > agrohorticulture or maize-wheat system (27.5 Mg ha− 1). Up to 33% lower SOC stocks were recorded in maize-wheat or agrohorticulture cropping systems than under the agroforestry land use system, thereby suggesting that conversion of forest land to agroecosystems can contribute to losses of up to 10.5 Mg ha− 1 SOC over time. Overall conclusion from this investigation is that SOC levels are strongly influenced by the prevailing land use systems.

Carbon-nitrogen isotope coupling of soil organic matter in a karst region under land use change, Southwest China

The soil stable carbon (C) and nitrogen (N) isotopes are widely used to indicate C3/C4 vegetation history, N sources and transformation processes, respectively. However, land use change, particularly converting forest into farm land, alters soil organic matter (SOM) sources and processes in soils, resulting in a hard understanding of soil C and N fate. In the present study, soil organic carbon (SOC) and soil organic nitrogen (SON) contents, and their stable isotope compositions (δ13C and δ15N) were determined in the five soil profiles under land use change (i.e., conversion of native forest land into shrub land, grass land, maize field, and paddy land) in Lobo county, Guizhou province, Southwest China. A coupling of 13C and 15N isotope in SOM under land use change was verified whether it could provide more accurate indications of sources and transformation processes.The SOC and SON contents of native forest land at the 0∼20 cm depth were significantly larger than these under other transformed lands. The SOC and SON contents decreased exponentially with increasing soil depth under all land use types, and showed opposite trends with soil pH. The C/N ratios of SOM in the soils under undisturbed native forest decreased from 10 to 7 with increasing soil depth, while an irregular fluctuation along soil profile was shown in other transformed lands. Similarly to the most study in the soils under C3 forest, the δ13C and δ15N values of SOM in the soils under native forest at the 0∼50 cm depth increased with increasing soil depth, with the range of −27.7‰∼−25.7‰ and 6.5‰∼10.0‰, respectively. While decreasing trends of them in the soils below 50 cm depth were attributed to the mixing of 13C and 15N-depleted organic matters from bedrocks. However, the δ13C and δ15N values of SOM along the soil profiles under other transformed lands were intensively irregularly fluctuated between −29.1‰ and −19.0‰, 1.2‰ and 7.9‰, respectively. The single δ13C and δ15N signals in the soil profiles of transformed lands indeed revealed the alterations of historical C3/C4 composition and N transformation processes after land use change, but these indications were not specific. The result of the coupling of 13C and 15N isotope under native forest land reveals a positive relationship between them, which associated with full plant-absorption against 15N-depleted inorganic nitrogen derived from SOM mineralization. This study suggests that the coupling of CN isotope fractionation more likely occurs in the C3 forest ecosystem with high N utilization efficiency. However, the replacement of native forest by farm land or grass land will reduce soil N utilization efficiency.