Estimation of above ground biomass and carbon stocks of mangrove forests from remote sensing and field data in mong cai city, quang ninh province during 2016 – 2019

` VIETNAM NATIONAL UNIVERSITY OF FORESTRY FOREST RESOURCES & ENVIRONMENTAL MANAGEMENT FACULTY ========================= STUDENT THESIS ESTIMATION OF ABOVE-GROUND CARBON STOCKS OF MANGROVE FORESTS FROM REMOTE SENSING AND FIELD DATA IN MONG CAI CITY, QUANG NINH PROVINCE DURING 2016 – 2019 Major: Natural Resources Management Code: D850101 Faculty: Forest Resources and Environmental Management Supervisor: Assoc Prof Dr Hai-Hoa Nguyen Student: Pham Van Bang Student ID: 1553090753 Class: K60 Natural Resources Management Course: 2015 – 2019 Advanced Education Program Developed in collaboration with Colorado State University, USA Ha Noi, 2019 ACKNOWLEDGEMENTS This research is supported by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 105.08-2017.05 On the occasion of completing this thesis, I would like to express deep gratitude to Assoc Prof Dr Hai- Hoa Nguyen who has guided and helped me in the process of the implementation and the completion of this study I sincerely thank teachers in Faculty of Forest Resources and Environmental Management for the encouragements and suggestions and for helping me to improve the quality of my study I would also like express our gratitude to the staffs of Mong Cai -Forest Protection Department and local people who living there for the enthusiastic support during my works Due to the limited knowledge and experiences, this report is not finalized yet I’m looking forward to receiving feedback from teachers and friends to improve this scientific research I sincerely thank you all! Ha Noi, 30, September, 2019 Author Pham Van Bang i ABBREVIATION GIS: Geographic Information System FAO: Food and Agriculture Organization UNEP: United Nations Environment Program ITTO: International Tropical Timber Organization ISE: Society for Mangrove Ecosystems UNESCO: United Nations Educational Scientific and Cultural Organization AGB: Above-ground Biomass AGC: Above-ground Carbon VIs: Vegetation Indices DBH: Diameter at Breast Height RS: Remote Sensing REDD+: Reduce Emission from Deforestation and forest Degradation GPS: Global Position System NDVI: Normalized Difference Vegetation Index SPSS: Statistical Package for the Social Sciences PFES: Payment for Forest Environment Services PES: Payment for Forest Services ii CONTENTS ACKNOWLEDGEMENTS…………………………………………………………………….i ABBREVIATION ii LIST OF TABLES v LIST OF DIAGRAMS v LIST OF FIGURES vi CHAPTER INTRODUCTION CHAPTER LITERATURE REVIEW 2.1 Overview of mangroves and remote sensing data 2.1.1 Overview of mangroves 2.1.2 Mangrove biomass and coastal services 2.2 Mangroves biomass and carbon stock in the worldwide 2.2.1 Mangroves biomass in the world 2.2.2 Mangroves biomass in Vietnam 2.3 Application of GIS and remote sensing to estimate mangrove biomass and carbon stock CHAPTER GOAL, OBJECTIVES AND METHODOLOGY 12 3.1 Overall Goal 12 3.2 Specific objectives 12 3.3 Equipments 12 3.4 Methods 13 3.4.1 Current status of mangrove forest in Mong Cai district, Quang Ninh province 13 3.4.2 Estimate above-ground biomass and carbon stocks of mangrove forest 14 3.4.3 Quantify changes in above-ground biomass and carbon stocks of mangrove forests 20 3.4.4 Propose solutions to enhance carbon stocks of mangrove forests in Mong Cai district, Quang Ninh province 21 CHAPTER NATURAL AND SOCIO-ECONOMIC CONDITIONS 22 4.1 Features of natural conditions 22 4.1.1 Geographical location 22 4.1.2 Topography and hydrology 22 4.2 Social-economic condition 23 CHAPTER RESULTS AND DISCUSSIONS 24 iii 5.1 Status of mangrove forests and management scheme in Mong Cai district, Quang Ninh province 24 5.1.1 Status of mangrove forests 24 5.1.2 Status map of mangrove forests 25 5.2 Above-ground biomass and carbon stocks of mangrove forests 30 5.2.1 Above-ground biomass and corresponding NDVI value of sub-plots in 2019 30 5.2.2 Development of regression models for biomass and carbon stock 30 5.3 Changes in above-ground biomass and carbon stock of mangrove forests during 2016 – 2019 in Mong Cai city, Quang Ninh province 38 5.3.1 Changes in above-ground biomass 38 5.3.2 Changes in above-ground carbon stocks 40 5.4 Solutions for mangrove management towards PFES in Mong Cai city, Quang Ninh province 42 5.4.1 Implementation of carbon payments for mangrove forests 42 5.4.2 Mechanism and policy solutions 44 5.4.3 Technical solutions 44 CHAPTER VI CONCLUSIONS, LIMITATIONS AND FURTHER STUDY 45 6.1 Conclusions 45 6.2 Limitations and further study 45 REFERENCES 47 iv LIST OF TABLES Table 2.1 Previous estimate of global extent of mangroves Table 2.2 About wood density of tree in mangrove forest Table 3.3 Wood density of mangrove species 17 Table 3.4 Regression models proposed for testing 19 Table 5.1: Area of mangrove forests in Mong Cai city (ha) 24 Table 5.2 Mangrove species distributed in Mong Cai city, Quang Ninh 25 Table 5.3 Accuracy assessment of classified map in 2019 27 Table 5.4 Accuracy assessment in 2016 29 Table 5.5 Mangrove forest areas in different years 29 Table 5.6 Above-ground biomass and corresponding NDVI of sub-plots in 2019 30 Table 5.7 Summary of models 30 Table 5.8 Above-ground biomass and carbon stocks of study site in 10/2016 and 8/2019 38 Table 5.9.Total above-biomass and carbon stock in 8/2019 43 LIST OF DIAGRAMS Diagram 3.1 Methods of contrition mangrove maps using NDVI 18 Diagram 3.2 Steps to improve map of change in biomass/carbon stocks 20 v LIST OF FIGURES Fig 3.1 Spatial distribution of field plot survey 15 Fig 3.2 Design of sampling plot for mangrove structures 16 Fig 4.1 Map of study site: (a) Vietnam; (b) Quang Ninh; (c) Mong Cai 22 Fig 5.1 Status map of mangrove forests in Mong Cai city, Quang Ninh province (Landsat 8, 15/08/2019) 26 Fig 5.2 Distribution of mangrove forests in Mong Cai city, Quang Ninh province 28 (Landsat 8, 09/10/2016) 28 Fig 5.4 Spatial distribution of above-ground biomass of Mong Cai City, Quang Ninh province in 2019 34 Fig 5.5 Spatial distribution of above-ground biomass of Mong Cai City, Quang Ninh province in 2016 35 Fig 5.6 Spatial distribution of carbon stocks of Mong Cai City, Quang Ninh province in 2019 36 Fig.5.7 Spatial distribution of carbon stocks of Mong Cai city, Quang Ninh province in 2016 37 Fig 5.8 Above-ground biomass changed in the period between 2016 and 2019 39 Fig 5.9 Above-ground carbon stocks changed in the period between 2016 and 2019 41 vi CHAPTER INTRODUCTION Mangroves are a group of plants that occur in the coastal intertidal zones of tropics and the subtropics Vietnam’s mangroves have been larger and rich and they play an important role for forest ecosystems, biodiversity and local livelihoods and development, fighting natural disasters, flooding, environmental protection of coastal areas, climate regulation and development economic and social of the country (Vashum, et al., 2012) Mangroves absorb a lot of CO by industrial activities and daily life discharge and they also produce lots of oxygen and help the air clean In Viet Nam, the effect of climate change is the one of the most affected countries from rising sea levels and the continuous storms which have caused serve damage to people and assets Mangroves bring high economic values and provide many products for human such as woods, building materials, sea foods and medicine Quang Ninh is a coastal province in Northeast Vietnam The province is seen as a miniature Vietnam because it consists of sea, islands, plain, midland, mountain and border As planned, Quang Ninh belongs to key economic region of both Northern region and Red River Delta This is a major coal mining province of Vietnam with Ha Long Bay, the natural heritage and natural wonders of the world Quang Ninh has a large area of mangroves (over 23,000 ha), mainly concentrate in localities such as Mong Cai, Tien Yen, Quang Yen and Van Don Quang Ninh's mangroves play an important role in ensuring ecological balance and dyke protection, as well as sheltering many species of seafood, serving people's lives Currently, the province is focusing on protecting and developing mangroves, thereby contributing to environmental protection, disaster mitigation and climate change prevention One of the environmental management tools is common in the world today is GISGeographic Information systems However, in recent years, new GIS just been developed in Vietnam This is to introduce topics and more widespread tool for field GIS environment sector Here, the subject will introduce one of GIS tools that vegetation index separated from the near-infrared band, infrared and red strip intermediate parameters from which could see the different characteristics of vegetation, such as biomass, index leaf area, photosynthetic capacity, total biomass products of seasonal plants can create These properties are related and depended greatly on the type of plant cover and weather, physiology, biochemistry and insect Technology for monitoring approximate characteristics of different ecosystems that allow identification standards and comparisons between them Multispectral satellite imagery, multi-resolution including very large, repeat the cycle time to help gather information quickly, sync, objectivity is deal for monitoring a number of factors affecting the forests in Quang Ninh as temperature and humidity This is a technical one rather strange for users in Vietnam Stemming from this reality our group choose the project name is “Estimation of aboveground biomass and carbon stocks of mangrove forests from remote sensing and field data in Mong Cai city, Quang Ninh province during 2016 – 2019” CHAPTER LITERATURE REVIEW 2.1 Overview of mangroves and remote sensing data 2.1.1 Overview of mangroves Roles and function of coastal significance Mangrove ecosystem is important coastal ecosystem with many functions which are not limited to ecological but also economical functions Although previous studies related to mangrove forests were not regarded as important, transitional communities with low productivity, most ecologists today view them as important ecosystem with high ecological productivity (Hsieh, et al., 2015) The major role of mangrove swamps is contribution to soil formation and stabilize coastline, mangroves act as filters for upland runoff, mangrove systems serve as the habitat of marine organism, mangrove produces large amount of detritus that may contribute to productivity in coastal waters In addition, mangrove forests also serve as protection for coastal communities against storms, serve as nurseries and refuge for many marine organisms that are commercial or sport value, serve as habitat of threatened species, serve as aesthetics and tourism (Hsieh, et al., 2015) Mangroves are among the most carbonrich forests in the tropics which containing 1,023 MgC/ha in average (Johnson, et al., 2016) “Blue carbon” is a term to explain the sequestered carbon in vegetated coastal ecosystems, especially mangrove forests, seagrass beds, and salt marshes (Arias-Ortiz, et al., 2018)  Definition of mangroves: Mangrove forest is a type of forest with tress growing in the big estuaries where the salt water mixes with the fresh water When the tide comes in, a part of the mangroves forest or the whole forest will be submerged; when the tide goes out, the forest will appear in its entirely (According to National Defense Magazine)  Roles and function of mangroves: Mangrove has the roles of ecological, economic, and social issues are very important in supporting the development of coastal areas In Biodiversity, home to an incredible array of species, mangroves are biodiversity hotspots They provide nesting and breeding habitat for fish and shellfish, migratory birds, and sea turtles An estimated 80% of the global fish catch relies on mangrove forests either directly or indirectly Livelihoods, the rural communities we work with are fishers and farmers who depend on their natural environment to provide for their families Healthy mangrove ecosystems mean healthy fisheries from which to fish, and healthy land on which to farm Mangroves are essential to maintaining water quality With their dense network of roots and Fig 5.5 Spatial distribution of above-ground biomass of Mong Cai City, Quang Ninh province in 2016 35 + The spatial distribution of above-ground carbon was illustrated by Fig 5.6 and Fig 5.7 Fig 5.6 Spatial distribution of carbon stocks of Mong Cai City, Quang Ninh province in 2019 36 Fig.5.7 Spatial distribution of carbon stocks of Mong Cai city, Quang Ninh province in 2016 37 Then, above-ground biomass and above-ground carbon of study are based on map were shown in Table 5.7: Table 5.8 Above-ground biomass and carbon stocks of study site in 10/2016 and 8/2019 Year Total Biomass (tons) Carbon Stock (tons) Change (tons) 2019 461950.10 219426.30 242523.8 2016 233849.03 111078.29 122770.74 Based on Fig.5.6, Fig.5.6 and Table 5.7, it indicated the lowest values of AGB were 3184.4 kg per pixel and 2305.1 kg per pixel in 2016 and 2019 respectively There were different results in two years surveyed as NDVI value of mangrove map in 2019 and 2016 was not the same Besides, the highest values of AGB gained 11597.4 kg per pixel in 2016, and 11249.9 kg per pixel in 2019 The results represented the same highest value of AGB since they had the same highest NDVI of mangrove map in 2016 and 2019 However, total above-ground biomass and carbon stocks in 2019 increased double in comparison with 2016.It was evident that the rapid growth of mangrove forests (more mature and healthy trees) in 2019 was higher than ones in 2016 5.3 Changes in above-ground biomass and carbon stock of mangrove forests during 2016 – 2019 in Mong Cai city, Quang Ninh province 5.3.1 Changes in above-ground biomass 38 Fig 5.8 Above-ground biomass changed in the period between 2016 and 2019 39 The Fig 5.8 illustrated the change of above-ground biomass of Mong Cai mangrove forest from 2016 to 2019 and the unit was presented by kilogram per pixel (kg/pixel) Overall, it could be seen that total above-ground biomass rose about 228101.07 tons Also, biomass of mangrove forests in some areas decreased significantly between 2016 and 2019 A forest of trees cutting down by local people and the barren forest areas could make biomass fall Meanwhile, the amount of biomass in other areas rose rapidly with appearance of many of trees that were growing and developing 5.3.2 Changes in above-ground carbon stocks 40 Fig 5.9 Above-ground carbon stocks changed in the period between 2016 and 2019 41 The figure 5.9 indicated the change of above-ground carbon of Mong Cai mangrove forest throughout studied period The carbon stocks of mangrove forests changed similar to above-ground biomass since both of them had a correlation coefficient each other by the equation AGC= 0.475* AGB Besides, a forest of trees cutting down by local people and the barren forest areas also made the carbon stocks change And, during the period between 2016 and 2019, total carbon stocks rose around 108348.0 tons 5.4 Solutions for mangrove management towards PFES in Mong Cai city, Quang Ninh province 5.4.1 Implementation of carbon payments for mangrove forests Improvement of REDD+ program for mangrove forests Polices government in payment environment services (PES) and the mechanisms of (REDD+) distribute sustainable forest management and reduce the impacts of climate change The mechanisms of REDD+: Forest carbon sequestration services are tied in with reducing emissions from deforestation and forest degradation and enhancing forest carbon stocks (REDD +), for which the government has approved a national action plan as the basic for reducing greenhouse gas emissions from forestry Policies of payment environmental services (PES): the basic idea of “payments for environmental services:, or PES is to create incentives for local people to protect environmental services In 2004, the government of Vietnam, drawing on the concept of PES, laid the foundation for a nationwide program of Payments for Forest Environmental Services (PEFES), set out in the revised Forest Protection and Development Law Method of estimation mangrove carbon sequestration Apply 156/2018/ND-CP Decree in enforcement of the Law on Forestry, Hydroelectric production facilities,; establishments producing and supplying clean water, organizations and individuals providing ecotourism, resort and entertainment services; for organizations and individuals engaged in production and business activities, which cause large greenhouse gas emissions; and establishments for aquaculture must pay forest environmental services following different Articles of the Law on Forestry In 2020, Quang Ninh is of four pilot provinces to pay forest carbon sequestration and storage services According to the draft decision, provinces were selected to pilot with 20 production facilities having large greenhouse gas sources; including thermal power production facilities and 11 cement production facilities 42 The draft also stipulates that the payment for coal producers and traders is VND / kWh (equivalent to USD $ / ton CO2) and VND 2,100 / ton of clinker (equivalent to USD $ 1.35 / tons of CO2) for organizations producing and trading in cement According to Mr Nguyen Van Vu, Director of Planning, Finance, General Department of Forestry, this payment is lower than the World Bank expected to buy and reduce emissions in the North Central region of USD / ton CO2; by only 11.2% (USD 1.35 / USD 11.13) the cost of generating ton of CO2 absorbed and stored by forest trees (USD 11.13) According to the calculation results, this payment will increase the cost of electricity production as well as the cost of cement production of the plants to about 0.29% and this increase is still in the range of actual cost increases of cement production sector is 0.3-1% / year The duration of the pilot period is from January 1, 2020 to December 31, 2021 Using the market price method, the value of forest carbon sequestration or storage is determined by the price of carbon credits (CER) on the world market applied under the clean development mechanism of the Protocol Kyoto Vc= Mc*Pc Where: Vc: Value of forest carbon sequestration and storage in USD or VND per hectare Mc: The carbon absorbed or stored in forest expressed in tons of CO2 per hectare Pc: the market price of CER carbon credits in USD or VND per tons of CO From the research results, mangrove forest area in 8/2019 in Mong Cai city, Quang Ninh province was 4413.4 ha, and estimation total above-biomass and carbon stocks shown as below table 5.8: Table 5.9.Total above-biomass and carbon stock in 8/2019 Mangrove forest area (ha) Total aboveground biomass 4413.4 (tons) 461950.1 Total carbon stock (tons) 219426.3 From the above results, apply the conversion coefficient according to international standards (1C = 3.67CO2) Total CO2 absorbed (Mc) = 219426.3*3.67= 805294.521 tons Price (Pc) USD/ tons of CO2 USD = 23285 VND (10-05/2019) Total money gained (Vc): 93 756 414 607 VND (~ 026 472.6 USD) 43 5.4.2 Mechanism and policy solutions Government policies play an important part in mangrove forest management and development Thesis proposes some solutions about mechanism and polices to control and improve mangrove forests -Reinforcing management of land use planning and mangroves Mangroves are natural forests that are not allocated to local people for aquaculture, but they can be contracted to households to protect and exploit mollusks from nature in mangrove forest - Applying regulation on Law on Protection and development forest, Land Law, Law, regulations on Alternative Afforestation and other legal documents must be serious carried out 5.4.3 Technical solutions - Enhancement of communication channels Need to strengthen propaganda on mass media: newspapers, radio and television for information on climate change, impacts of climate change, the role of mangrove forests and coastal protection forest in mitigating coastal erosion and other damage caused by extreme natural disasters There should be a training of specialized staff, organizing training courses for social units in the area of construction methods and deployment models coastal livelihoods to improve people’s income to contribute mangroves to the cause of protection and development of mangroves - Improvement of techniques for planting mangrove trees in different natural conditions such as nutrient, salinity, soil properties 44 CHAPTER VI CONCLUSIONS, LIMITATIONS AND FURTHER STUDY 6.1 Conclusions From the research results, total mangrove area of Mong Cai city, Quang Ninh province was about 3405.3 in 2016 and 4413.4 in 2016 Mangrove forests have been protected directly by commune people’s committees with the support of Forest Protection Department of Mong Cai city In addition, distribution of mangrove forests was divided in three land cover types including water, bare land, and mangrove, and accuracy assessments of map classified in 2016 and 2019 was greater more than 80 % With the results, total above-ground biomass and carbon stocks of mangrove in 2016 were 233849.01 tons and 111078.30 tons respectively Meanwhile, those results of mangrove in 2019 were 461950.1 tons and 219426.3 tons respectively The changes in above-ground biomass and carbon stocks of mangrove forests during the period between 2016 and 2019 were clear Both of them were rose about 228101.1 tons and 108348.0 tons from 10/2016 to 8/2019 correspondingly Besides, forest of trees cutting down by local people and the barren forest areas, meaning deforestation and forest degradation, made some areas fall The best model for biomass calculation is quadratic regression with the equation: AGB= 2361.79 + 1724.51 * NDVI + 13093.32 * NDVI2 Therefore, the study recommended variety of solutions to enhance biomass and carbon stocks in Mong Cai city 6.2 Limitations and further study Although it has gained some significant results, study still remains shortcomings The scope of study is quite large, and some coastal areas with mangroves could be missing And due to the limited time, the study did not assess fully related issues such as evaluating the growth and development of trees, not investigate deeply the accumulation of below-ground To overcome the shortcoming and achieve better results, further studies should be conducted Firstly, a number of sampling points should be increased for enhancing the 45 accuracy of image classifications In addition, further study should use higher spatial resolution images for mangrove change mapping Other matters such as bare land, other plants should be taken into account when classifying mangroves For drives of mangrove change and policy, society should be further examined in relation to mangrove management, such as impacts of financial policies and land use planning 46 REFERENCES Arias-Ortiz, A., Serranno, O., Masqué, P., Lavery, P.S., Mueller, U., Kendrick, G.A., Rozaimi, M., Esteban, A., Fourqurean, J.W., Marbà, N., Mateo, M.A., Murray, K., Rule, M.J., Duarte, C,M., (2018) A marine heatwave drives massive losses from the world’s largest seagrass carbon stocks Nature Climate Change 8:338-344 Fu, W., Wu, Y., (2011): Estimation of above –ground biomass of different mangrove trees based on canopy diameter and tree height Procedia Environmental Sciences, 2011, Page 2189-2194 Hsieh, H.L., Lin, H.J., Shih, S.S., Chen, C.P., (2015): Ecosystem Functions Connecting Contributions from Ecosystem Services to Human Wellbeing in Mangrove System in Northern Taiwan: A review International Journal 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