Investigation of vegetation structure and carbon storage in lower u minh wetland in vietnam and muthurajawela wetland in sri lanka

PhD UNIVERSITY OF SRI YAYEWARDENEPURA, SRI LANKA FACULTY OF GRADUATE STUDIES PHAN TRUONG KHANH INVESTIGATION OF VEGETATION STRUCTURE AND CARBON STORAGE IN LOWER U MINH WETLAND IN VIETNAM AND MUTHURAJAWELA WETLAND IN SRI LANKA Ph.D thesis by PHAN TRUONG KHANH 2018 Colombo, March, 2018 INVESTIGATION OF VEGETATION STRUCTURE AND CARBON STORAGE IN LOWER U MINH WETLAND IN VIETNAM AND MUTHURAJAWELA WETLAND IN SRI LANKA Ph.D thesis by PHAN TRUONG KHANH Advisor: Professor S.M.C.U.P Subasinghe Professor Vo Quang Minh Thesis submitted to the University of Sri Jayewardenepura for the award of the Degree of Doctor of Philosophy in Environmental Science on 31st March 2018 DECLARATION The work described in this thesis was carried out by me under the supervision of Professor S.M C.U.P Subasinghe and a report on this has not been submitted in whole or in part to any university or any other institution for another Degree/Diploma Signature ……………………… Phan Truong Khanh Date:…………………………… I certify that the above statement made by the candidate is true and that this thesis is suitable for submission to the Faculty of Graduate Studies, University of Sri Jayewardenepura, Sri Lanka for the purpose of evaluation Signature:……………………………… Internal Supervisor Professor S.M.C.U.P Subasinghe Senior Lecturer Department of Forestry and Environmental Science University of Sri Jayewardenepura Sri Lanka Date:………………………… SUPERVISOR CERTIFICATE I certify that the candidate has incorporated all corrections additions and amendments recommended by the examiners to this version of the PhD thesis Signature:……………………………… Internal Supervisor Professor S.M.C.U.P Subasinghe Senior Lecturer Department of Forestry and Environmental Science University of Sri Jayewardenepura Sri Lanka Date:………………………… Publications during candidature Khanh, P.T., Subasinghe, S.M.C.U.P (2017) Identification of Vegetation Change of Lower U Minh National Park of Vietnam from 1975 to 2015 Journal of Tropical Forestry and Environment, 7(2): 14-26 Phan Truong Khanh, Subasinghe S.M.C.U.P (2018) An Assessment of the Carbon Stocks of Meleleuca Forests in the Lower U Minh National Park in Ca Mau Province of Southern Vietnam American Journal of Engineering Research (AJER), 7(5): 305-315 Phan Truong Khanh, Subasinghe S.M.C.U.P (2018) Estimating Above-Ground Biomass of the Mangrove Communities in the Muthurajawela Wetland, Sri Lanka International Journal of Science and Research (IJSR), 7(5): 86-93 Phan Truong Khanh, Subasinghe S.M.C.U.P (2018) Identification of Vegetation Change of Muthurajawela Wetland in Sri Lanka from 1992 to 2015 by Using GIS-Remote Sensing International Journal of Computational Engineering Research (IJCER), 8(5): 42-52 TABLE OF CONTENTS Page List of tables - vi List of figures x List of abbreviations xv Acknowledgments xvii Abstract - xviii CHAPTER 1: INTRODUCTION 1.1 Background 1.2 The objectives of the proposed resarch -13 CHAPTER 2: 2.1 LITERATURE REVIEW 14 Common wetland types - 14 2.1.1 Freshwater wetlands 16 2.1.1.1 Freshwater wetlands in the Mekong delta, Vietnam 16 2.1.1.2 Freshwater wetlands in Sri Lanka 18 2.1.2 Saltmarsh wetlands - 20 2.2 2.1.2.1 Saltmarsh wetlands in Vietnam - 21 2.1.2.2 Saltmarsh wetlands in Sri Lanka - 23 Functions and importance of wetlands - 24 2.2.1 Carbon storage 24 2.2.2 Biodiversity and habitat protection - 27 2.2.3 Wood supply -28 2.2.4 Non-wood forest products supply 28 2.2.5 Flood control, shoreline and storm protection 29 2.2.6 Social benefits - 29 i 2.2.7 2.3 2.4 Tourism -30 Characteristics of Melaleuca cajuputi - 31 2.3.1 Distribution of Melaleuca forests - 32 2.3.2 The value of Melaleuca forests - 33 Mangrove ecosystems 34 2.4.1 2.4.2 Definition and the role of mangrove ecosystems - 34 2.4.1.1 Definition of mangrove 34 2.4.1.2 The role of mangrove ecosystems 34 2.4.1.3 Economic value of Muthurajawela wetland - 36 Distribution of mangrove ecosystems 37 2.4.2.1 2.5 2.6 2.7 Mangrove forest in Sri Lanka - 41 Biomass and carbon storage in forests 44 2.5.1 Biomass and carbon storage in Melaleuca ecosystems 49 2.5.2 Biomass and carbon storage in mangrove ecosystems 54 2.5.2.1 Biomass and carbon storage in mangrove of Sri Lanka 57 2.5.2.2 Biomass and carbon storage in forests of Sri Lanka - 61 Remote sensing and GIS approaches used in wetland survey - 63 2.6.1 Low spatial resolution optical systems - 66 2.6.2 Medium spatial resolution optical systems 67 2.6.3 High spatial resolution optical systems 68 2.6.4 GIS procedures using imagery 73 Application of remote sensing and GIS techniques in wetland mapping 74 2.7.1 Application of remote sensing and GIS techniques on wetland studies in Vietnam 77 ii 2.7.2 Application of remote sensing and GIS techniques on wetland studies in Sri Lanka - 79 2.8 Image classification approach 82 2.8.1 Unsupervised classification 82 2.8.2 Supervised classification - 83 CHAPTER 3: 3.1 METHODOLOGY 96 Materials and methods - 85 3.1.1 Materialss - - 85 3.1.2 Methods - 87 3.1.2.1 Literature study - 89 3.1.2.2 Field investigations 89 3.1.2.3 Laboratory analysis 96 3.1.2.4 Data analysis 96 CHAPTER 4: RESULTS AND DISCUSSION - 109 4.1 Building the map of vegetation cover 109 A Lower U Minh National Park - -109 B 4.1.1 Normalized difference vegetation index (NDVI) - 109 4.1.2 Unsupervised classification 111 4.1.3 Supervised classification - 115 4.1.4 The changes of vegetation cover from 1975 to 2015 119 Muthurajawela wetland - 122 4.1.5 Normalized difference vegetation index (NDVI) 122 4.1.6 Unsupervised classification 125 4.1.7 Supervised classification - 129 iii 4.1.8 The changes of vegetation cover from 1975 to 2015 132 4.1.9 General discussion and comparison of survey approaches between lower U Minh national park and Muthurajawela wetland 135 4.2 Vegetation structure - 140 A Lower U Minh national park -140 4.2.1 Natural Melaleuca cajuputi forest zone (grown on the peatland) - 149 4.2.2 Plantation Melaleuca cajuputi forest zone (grown on the clay soil) - 151 B Muthurajawela wetland - -158 4.3 Biomass and CO2 storage 172 A Melaleuca cajuputi forests-lower U Minh national park - 172 4.3.1 The growth parameters of Melaleuca cajuputi forests - 172 4.3.1.1 Natural Melaleuca cajuputi forest - 173 4.3.1.2 Plantation Melaleuca cajuputi forest 173 4.3.2 The above-ground biomass of Melaleuca cajuputi 176 4.3.3 Estimation of below-ground biomass of Melaleuca cajuputi - 181 4.3.4 Mathematical models built for the relationship of biomass and DBH - 183 4.3.5 Above-below ground biomass of Melaleuca cajuputi populations 188 4.3.6 Carbon content and CO2 storage in the Melaleuca cajuputi populations - 190 4.3.7 B Estimate the cost of CO2 - 192 Muthurajawela wetland 196 4.3.8 The growth parameters of mangroves forests - 196 4.3.9 Mathematical models built to conduct the biomass of woody iv Appendix 5b: Green above-ground biomass of each part of standard B cylindrical in the Muthurajawela wetland DBH (cm) Stem (kg) Branch (kg) Leaf (kg) Total (kg) 3.60 2.97 0.51 0.31 3.79 3.90 3.36 0.6 0.42 4.38 4.20 3.75 0.61 0.47 4.83 4.80 4.18 0.68 0.53 5.39 5.50 4.75 0.75 0.64 6.14 6.20 5.87 1.01 0.75 7.63 6.90 6.69 1.16 0.86 8.71 7.70 9.95 1.82 1.28 13.05 8.92 14.05 2.45 1.75 18.25 9.80 21.36 3.35 2.56 27.27 11.30 34.33 5.47 3.91 43.71 12.11 39.89 6.18 4.53 50.60 13.20 52.51 7.87 6.05 66.43 14.33 72.67 10.37 8.41 91.45 15.93 98.13 13.85 9.76 121.74 Average 24.96 3.78 2.82 31.56 290 Appendix 5c: Green above-ground biomass of each part of standard Annona glabra in the Muthurajawela wetland DBH (cm) Stem (kg) Branch (kg) Leaf (kg) Total (kg) 3.20 2.54 0.38 0.27 3.19 3.50 2.98 0.45 0.38 3.81 4.50 3.41 0.55 0.41 4.37 5.41 4.66 0.72 0.57 5.95 5.73 5.32 0.81 0.62 6.75 6.05 6.76 1.02 0.86 8.64 6.69 8.28 1.35 0.95 10.58 8.28 14.53 2.31 1.72 18.56 8.60 15.78 2.47 1.82 20.07 8.92 20.38 3.39 2.26 26.03 10.20 33.86 5.21 3.77 42.84 10.50 34.65 5.73 3.96 44.34 12.11 41.39 6.29 4.65 52.33 13.20 47.84 7.52 5.20 60.56 14.33 58.81 8.73 5.45 72.99 Average 20.08 3.13 2.19 25.40 291 Appendix 5d: Green above-ground biomass of each part of others woody species in the Muthurajawela wetland DBH (cm) Stem (kg) Branch (kg) Leaf (kg) Total (kg) 4.33 3.57 0.53 0.39 4.49 4.46 3.75 0.54 0.47 4.76 4.78 4.27 0.66 0.54 5.47 5.73 5.95 0.95 0.85 7.75 6.05 7.39 1.09 0.93 9.41 6.37 8.67 1.32 1.09 11.08 7.64 14.17 2.19 1.52 17.88 8.28 18.91 3.20 1.65 23.76 9.55 24.55 4.01 2.84 31.4 10.46 32.15 5.04 3.68 40.87 12.43 39.11 6.59 4.03 49.73 13.38 48.99 7.98 5.46 62.43 14.11 53.91 8.08 6.09 68.08 15.13 64.65 9.71 7.80 82.16 16.56 75.84 10.18 8.29 94.31 Average 27.06 4.14 3.04 34.24 Others woody species: Sonneratia caseolaris, Hibiscus tiliaceus, Excoecaria agallocha, Cerbera manghas, Syzygium caryophyllatum, Dolichandron spathacea and Pandanus tectorius 292 Appendex 6a: Average density, height, DBH of woody species on peatland in natural forest of lower U Minh National Park Plot Number of trees Height (m) DBH (cm) N-1 91 15.53 20.90 N-2 51 15.88 18.2 N-3 76 13.92 14.34 N-4 72 14.31 18.55 N-5 108 14.62 16.45 N-6 97 13.19 13.78 N-7 85 15.14 17.02 N-8 87 14.10 14.75 N-9 92 13.90 14.20 N-10 83 15.71 19.78 N-11 87 15.41 19.81 N-12 86 15.59 20.09 293 Appendix 6b: Average density, height, DBH of woody species on clay soil in plantation forest of lower U Minh National Park Plot Number of trees Height (m) DBH (cm) P-1 51 12.50 9.73 P-2 52 12.80 10.13 P-3 48 12.70 9.97 P-4 51 12.70 9.85 P-5 52 12.00 9.48 P-6 54 12.10 9.95 P-7 56 12.60 10.18 P-8 58 12.70 10.17 P-9 63 12.50 9.83 P-10 61 12.80 9.94 P-11 66 12.60 9.82 P-12 68 12.10 9.43 P-13 71 11.90 9.25 P-14 69 12.20 9.48 P-15 68 12.30 9.54 P-16 45 12.80 10.33 P-17 61 10.90 8.42 P-18 72 10.90 8.76 P-19 75 10.51 8.46 P_20 73 10.30 8.13 P-21 75 9.70 7.61 294 P-22 75 9.40 7.40 P-23 63 12.00 9.53 P-24 68 10.90 8.57 P-25 59 10.54 8.10 P-26 65 11.20 8.96 P-27 75 11.00 8.67 P-28 76 10.10 7.80 P-29 51 11.04 9.03 P-30 70 11.67 8.58 P-31 68 10.90 8.55 P-32 56 10.44 8.14 P-33 71 10.30 8.04 295 Appendix 7a: Average density, height, DBH of woody species in low dense forest of Muthurajawela wetland Plot Number of trees DBH (cm) Height (m) L-1 19 8.42 6.76 L-2 22 7.94 7.11 L-3 24 8.13 6.93 L-4 17 6.99 6.82 L-5 18 7.84 8.17 L-6 17 9.03 9.74 L-7 19 9.44 6.76 L-8 22 8.26 7.14 L-9 24 8.13 6.93 L-10 20 9.12 9.30 L-11 18 7.84 9.00 L-12 17 9.91 10.50 296 Appendix 7b: Average density, height, DBH of woody species in medium dense forest of Muthurajawela wetland Plot Number of trees DBH (cm) Height (m) M-1 32 7.63 6.40 M-2 28 7.32 4.94 M-3 31 7.21 5.56 M-4 27 11.31 10.19 M-5 30 12.79 13.15 M-6 32 14.59 13.77 M-7 32 7.72 6.48 M-8 28 7.57 4.85 M-9 31 7.40 5.58 M-10 27 11.31 9.93 M-11 31 13.12 13.85 M-12 31 14.03 13.99 297 Appendix 7c: Average density, heigh, DBH of woody species in high dense forest of Muthurajawela wetland Plot Number of trees DBH (cm) Height (m) H-1 40 7.86 6.56 H-2 42 8.12 6.94 H-3 44 7.79 7.34 H-4 36 11.71 11.18 H-5 37 12.80 13.35 H-6 38 12.39 11.79 H-7 45 7.86 6.59 H-8 42 8.03 6.99 H-9 49 8.12 7.56 H-10 44 10.73 9.66 H-11 47 11.63 13.26 H-12 45 11.48 11.02 298 Appendix 8a: Compare to different diameter groups of M cajuputi in natural forest of U Minh National Park by One-way ANOVA statistics ANOVA Sum of Squares df 727,996.949 Within Groups 80,061.458 28 Total 808,058.407 31 261,954.377 87,318.126 56.890 Within Groups 42,976.391 28 1,534.871 Total 304,930.768 31 Green_total_ Between N Groups Dry_total_N Mean Between Groups Square F Sig 242,665.650 84.868 000 2,859.338 000 Duncan: Compare to green biomass between diameter classes of M cajuputi in natural forest of U Minh National Park Subset for alpha = 0.05 Repeat_N N D=5-10cm 25.3425 D=10-15cm 68.3312 D=15-20cm D>20cm 171.10 414.41 Sig .119 1.000 1.000 Means for groups in homogeneous subsets are displayed Duncan: Compare to dry_ biomass between diameter classes of Melaleuca cajuputi in natural forest of U Minh National Park 299 Subset for alpha = 0.05 Repeat_N N D=5-10cm 15.0962 D=10-15cm 41.4362 D=15-20cm D>20cm 104.28 248.70 Sig .190 1.000 1.000 Means for groups in homogeneous subsets are displayed Appendix 8b: Compare to different diameter groups of M cajuputi in plantation forest of U Minh National Park by One-way ANOVA statistics ANOVA Sum of Squares Between 86,350.147 Within Groups 5,689.626 28 Total 92,039.773 31 37,498.205 Within Groups 2,380.837 28 Total 39,879.042 31 Groups Green_total_P Between Groups Dry_total_P df Mean Square F Sig 28,783.382 141.650 0.000 203.201 12,499.402 147.000 0.000 85.030 Ducan: Compare to green biomass between diameter classes of M cajuputi in plantation forest of U Minh National Park Repeat_P N Subset for alpha = 0.05 300 D