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

1.

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.


2.

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.

3.

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.

4.

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

1.1

Background-------------------------------------------------------------------------------- 1

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


species ----------- ------------------------------------------------------------ 197
4.3.10

The above-ground biomass of mangrove populations ----------------- 207

4.3.11


Estimate the cost of CO2 --------------------------------------------------- 214

CHAPTER 5:

CONCLUSIONS ------------------------------------------------------ 216

5.1

Identification of vegetation structure and cover area change---------------------216

5.2

An assessment of the carbon stocks ------------------------------------------------ 216
5.2.1

The lower U Minh national park ----------------------------------------- 216

5.5.2

The Muthurajawela wetland----------------------------------------------- 217

CHAPTER 6: RECOMMENDATIONS --------------------------------------------- 219
6.1

Identification of vegetation change by GIS technology ------------------------ 219

6.2

Vegetation structure ----- ------------------------------------------------------------ 220


6.3

An assessment of the carbon stocks------------------------------------------------ 220

REFERENCES-------------------------------------------------------------------------------222
APPENDICES------------------------------------------------------------------------------- 269

v


LIST OF TABLES
Table 2.1

The 15 most mangrove-rich countries and their cumulative
percentages --------------------------------------------------------------------- 37

Table 2.2

List of allometric equations applied to examine the stand biomass
of the Melaleuca forests in the study sites of Vietnam ------------------ 52

Table 2.3

Allometric equations for estimating biomass in mangrove forests ---- 59

Table 3.1

Landsat time series used in the study -------------------------------------- 85


Table 3.2

The characteristics of the landsat images ---------------------------------- 87

Table 4.1

Patterns illustration of the 4,3,2 spectrum channel and the 5,4,3
spectrum channel for the vegetation classes of the
lower U Minh national park ----------------------------------------------- 109

Table 4.2

NDVI for the vegetation classes of the lower U Minh
national park ----------------------------------------------------------------- 111

Table 4.3

Error matrix of vegetation cover classification of the
lower U Minh national park in 2015 ------------------------------------- 117

Table 4.4

Assess the accuracy of the Landsat image interpretation of
vegetation cover classification in the lower U Minh
national park in 2015 ------------------------------------------------------ 118

Table 4.5

Patterns illustrate the 4,3,2 spectrum channel and the 5,4,3
spectrum channel for the vegetation classes of the

Muthurajawela wetland ---------------------------------------------------- 122

Table 4.6

Normalized difference vegetation index value (NDVI) --------------- 124

vi


Table 4.7

Error matrix of vegetation cover classification of the
Muthurajawela wetland in 2015------------------------------------------ 131

Table 4.8

Assess the accuracy of the Landsat image interpretation of
vegetation cover classification in the Muthurajawela wetland
in 2015 ------------------------------------------------------------------------ 131

Table 4.9

Percentage of presence of woody species in the lower U Minh
national park in 2015 ------------------------------------------------------ 142

Table 4.10

List of plant families and species recorded in the lower U Minh
national park of Vietnam --------------------------------------------------- 143


Table 4.11

Percentage presence of woody species in the Muthurajawela
wetland in 2015 ------------------------------------------------------------- 159

Table 4.12

List of plant families and species recorded in the Muthurajawela
wetland ----------------------------------------------------------------------- 161

Table 4.13

Presence of plant species in the lower U Minh
national park in 2015 ------------------------------------------------------- 173

Table 4.14

The growth parameters of Melaleuca cajuputi trees ------------------- 174

Table 4.15a

The above-ground biomass of individual M. cajuputi tree in
natural forest ----------------------------------------------------------------- 176

Table 4.15b

The above-ground biomass of individual M. cajuputi tree in
plantation forest ------------------------------------------------------------- 177

Table 4.16a


The below-ground biomass of individual Melaleuca cajuputi tree
in natural forest -------------------------------------------------------------- 182

Table 4.16b

The below-ground biomass of individual Melaleuca cajuputi tree
in plantation forest ---------------------------------------------------------- 182

vii


Table 4.17

List of allometric equations applied to estimate biomass of the
Melaleuca cạuputi forests in the lower U Minh national park ------- 184

Table 4.18

The percentage of green biomass difference in plantation forest
between the survey value and the simulation value -------------------- 186

Table 4.19

The percentage of green biomass difference in natural forest
between the survey value and the simulation value -------------------- 187

Table 4.20

Estimated the total biomass of Melaleuca cajuputi forests ----------- 190


Table 4.21

The carbon content and CO2 storage in the lower U Minh
national park ----------------------------------------------------------------- 191

Table 4.22

The growth parameters of mangrove trees ------------------------------ 197

Table 4.23a

The green above-ground biomass of individual mangrove trees ----- 212

Table 4.23b

The dry above-ground biomass of individual mangrove tree --------- 200

Table 4.24

List of allometric equations applied to estimate biomass of the
mangrove trees in Muthurajawela wetland ----------------------------- 201

Table 4.25

The percentage of green above-ground biomass difference for
R. mucronata between the survey value and the simulation value--- 204

Table 4.26


The percentage of green above-ground biomass difference for
A. glabra between the survey value and the simulation value ------ 205

Table 4.27

The percentage of green above-ground biomass difference for
B. cylindrical between the survey value and the simulation value -- 206

Table 4.28

The percentage of green biomass difference for other mangrove
species (Sonneratia caseolaris, Hibiscus tiliaceus, Excoecaria
agallocha, Cerbera manghas, Syzygium caryophyllatum,
Dolichandron spathacea and Pandanus tectorius)

viii


between the survey value and the simulation value -------------------- 207
Table 4.29a

Estimated the total green above-ground biomass of mangrove
populations------------------------------------------------------------------- 208

Table 4.29b

Estimated the total dry above-ground biomass of mangrove
populations------------------------------------------------------------------- 208

Table 4.30a


Estimated the total green above-ground biomass of mangrove
forests in the Muthurajawela wetland ------------------------------------ 213

Table 4.30b

Estimated the total dry above-ground biomass of mangrove
forests in the Muthurajawela wetland ------------------------------------ 213

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LIST OF FIGURES

Figure 1.1

Location of the lower U Minh national park in Mekong delta,
Vietnam-------------------------------------------------------------------------- 9

Figure 1.2

View of the lower U Minh national park of Vietnam -------------------- 10

Figure 1.3

Location of the Muthurajawela wetland of Sri Lanka ------------------- 11

Figure 1.4

View of the Muthurajawela wetland of Sri Lanka ----------------------- 12


Figure 2.1

Map showing areas of special use forests and 10 priority sites
for biodiversity conservation in the Mekong delta ----------------------- 18

Figure 2.2

Kumana villu-natural swamp lake ------------------------------------------ 19

Figure 2.3

Livelihood model for coastal communities in the Mekong delta,
Vietnam------------------------------------------------------------------------- 21

Figure 2.4

Carbon cycle in wetlands ---------------------------------------------------- 25

Figure 2.5

Melaleuca cajuputi forest in the lower U Minh national park ---------- 32

Figure 2.6

Worldwide distribution of mangroves ------------------------------------- 40

Figure 2.7

Global mangrove forests distribution-2000 ------------------------------- 40


Figure 2.8

Proportion of threatened (Critically Endangered, Endangered,
and Vulnerable) mangrove species. ---------------------------------------- 41

Figure 2.9

Distribution of mangrove vegetation in Sri Lanka ----------------------- 42

Figure 3.1

Summary of methodology used in the study ------------------------------ 88

Figure 3.2

Layout of sample plots in the lower U Minh national park of
Vietnam scale 1:25,000 ------------------------------------------------------ 90

Figure 3.3

Layout of sample plots in Muthurajawela wetland of Sri Lanka
scale 1:50,000 ----------------------------------------------------------------- 91

x


Figure 3.4

Location of the training field samples in Muthurajawela wetland

scale 1:50,000 ----------------------------------------------------------------- 93

Figure 3.5

Location of the training field samples in the lower U Minh
national park scale 1:25,000 ------------------------------------------------- 94

Figure 4.1a

The vegetation cover map of the lower U Minh national park
in 1975 built by unsupervised classification ---------------------------- 112

Figure 4.1b

The vegetation cover map of the lower U Minh national park
in 1995 built by unsupervised classification ---------------------------- 113

Figure 4.1c

The vegetation cover map of the lower U Minh national park
in 2015 built by unsupervised classification ---------------------------- 114

Figure 4.1d

The vegetation cover map of the lower U Minh national park
in 2015 built by supervised classification ------------------------------- 116

Figure 4.2

The vegetation cover area of the lower U Minh national park

1975, 1995 and 2015 ------------------------------------------------------- 120

Figure 4.3

The changes percentage of vegetation area in the lower U Minh
national park 1975-2015 --------------------------------------------------- 121

Figure 4.4

The normalized difference vegetation index map ----------------------- 124

Figure 4.5

The vegetation cover map of the Muthurajawela wetland in 1992
built by unsupervised classification -------------------------------------- 126

Figure 4.6

The vegetation cover map of the Muthurajawela wetland in 2001
built by unsupervised classification -------------------------------------- 127

Figure 4.7

The vegetation cover map of the Muthurajawela wetland in 2015
built by unsupervised classification -------------------------------------- 128

xi


Figure 4.8


The vegetation cover map of the Muthurajawela wetland in 2015
built by supervised classification ----------------------------------------- 130

Figure 4.9

Vegetation cover change of Muthurajawela wetland in 1992,
2001 and 2015 --------------------------------------------------------------- 133

Figure 4.10

The changes percentage of vegetation area in Muthurajawela
wetland 1992-2015 --------------------------------------------------------- 134

Figure 4.11

Presence of plant species in the lower U Minh national park
in 2015------------------------------------------------------------------------ 141

Figure 4.12

Woody species zonation at the lower U Minh national park
in 2015------------------------------------------------------------------------ 143

Figure 4.13

Melaleuca cajuputi forests on clay soil in the lower U Minh
national park ----------------------------------------------------------------- 146

Figure 4.14


Melaleuca cajuputi forests on peat soil in the lower U Minh
national park ----------------------------------------------------------------- 147

Figure 4.15

Phragmites karka on the dike in the lower U Minh national park --- 147

Figure 4.16

Nepenthes mirabilis in the lower U Minh national park -------------- 148

Figure 4.17

Dischidia rafflesoawa in the lower U Minh national park ----------- 148

Figure 4.18

Ficus pisocarpa in the lower U Minh national park ------------------- 149

Figure 4.19

Presence of plant species in natural M. cajuputi forest in 2015 ------ 150

Figure 4.20

Presence of plant species in plantation M. cajuputi forest in 2015 -- 152

Figure 4.21


Pistia stratiotes in the lower U Minh national park -------------------- 154

Figure 4.22

Ceratopteris thalictroides in the lower U Minh national park-------- 154

Figure 4.23

Eichhornia crassipes in the lower U Minh national park ------------- 155

Figure 4.24

Eleocharis dulcis in the lower U Minh national park ------------------ 155

xii


Figure 4.25

Ludwigia adscendens in the lower U Minh national park ------------- 156

Figure 4.26

Woody species distribution in high, medium and low density
awear of Muthurajawela wetland ---------------------------------------- -160

Figure 4.27

Rhizophora mucronata in Muthurajawela wetland--------------------- 168


Figure 4.28

Annona glabra in Muthurajawela wetland ------------------------------ 169

Figure 4.29

Avicennia marina in Muthurajawela wetland --------------------------- 169

Figure 4.30

Bruguiera cylindrical in Muthurajawela wetland ---------------------- 170

Figure 4.31

The green biomass of stems, branches and leaves of M. cajuputi---- 178

Figure 4.32

The dry biomass of stems, branches and leaves of M. cajuputi ------ 180

Figure 4.33

The ratio of dry to green biomass of stems, branches and
leaves of M. cajuputi in national forest and plantation forest -------- 181

Figure 4.34

Below-ground biomass of Melaleuca cajuputi tree -------------------- 183

Figure 4.35


Relationship between observed values results of biomass
predicting equation, natural forest, above ground biomass ----------- 184

Figure 4.36

Relationship between observed values results of biomass
predicting equation, natural forest, below ground biomass ----------- 185

Figure 4.37

Relationship between observed values results of biomass
predicting equation, plantation forest,above ground biomass -------- 185

Figure 4.38

Relationship between observed values results of biomass
predicting equation, plantation forest, below ground biomass ------- 186

Figure 4.39

Difference of green biomass between natural and plantation
forest -------------------------------------------------------------------------- 189

Figure 4.40

The ratio of dry to green biomass of woody species in the
Muthurajawela wetland ---------------------------------------------------- 199

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Figure 4.41

Relationship between observed values results of biomass
predicting equation, R. mucronata, above-ground biomass ----------- 202

Figure 4.42

Relationship between observed values results of biomass
predicting equation B. cylindrica, above-ground biomass------------- 202

Figure 4.43

Relationship between observed values results of biomass
predicting equation Annona glabra, above-ground biomass ---------- 203

Figure 4.44

Relationship between observed values results of biomass
predicting equation, others woody species,
above-ground biomass ----------------------------------------------------- 203

Figure 4.45

Compare the biomass differences between four plant species -------- 209

Figure 4.46

Compare the densities differences of woody species between

three densities groups: Low, medium, high ----------------------------- 210

Figure 4.47

The vegetation cover map of the Muthurajawela wetland ------------ 211

Figure 4.48

The area of vegetation classes of the Muthurajawela wetland -------- 212

Figure 4.49

Compare the biomass differences of woody species between
three densities groups: Low, medium, high ----------------------------- 212

xiv


LIST OF ABBREVIATIONS

AGB

Above Ground Biomass

BGB

Below Ground Biomass

CBD


Convention on Biological Diversity

CDM

Clean Development Mechanism

DBH

Diameter at Breast Height

DGPS

Differential Global Positioning System

EPA

Environmental Protection Agency

ETM

Enhanced Thematic Mapper

ETM+

Enhanced Thematic Mapper Plus

FAO

Food and Agricultural Organization


GCP

Ground Control Point

GIS

Geographic Information Systems

GLOVIS

Global Visualization Viewer

GPS

Global Positioning System

GtC

Giga tons Carbon

IPCC

Intergovernmental Panel on Climate Change

ISODATA

Iterative Self-Organizing Data Analysis Technique Algorithmv

Landsat TM


Landsat Thematic Mapper

LANDSAT

Land Observation Satellite

LULUCF

Land Use, Land-Use Change and Forestry

MLC

Maximum Likelihood Classifier

Mt

Megatons

MtC

Million tons carbon
xv


MSS

Multi Spectral Scanner

NDVI


Normalized Difference Vegetation Index

NIR

Near Infrared Reflectance

ppm

Parts per million

REDD+

Reducing Emissions from Deforestation and Forest Degradation plus

RS

Remote Sensing

SOC

Soil organic carbon

SPOT

Satellite Pour I’Observation de la Terre

STRP

Scientific and Technical Review Panel


tC

Ton carbon

tC/ha

Ton carbon per hectare

t/ha

Tons per hectare

TIFF

Tagged Image File Format

TM

Thematic Mapper

UNCED

United Nations Conference on Environment and Development

UNEP

United Nations Environment Program

UNESCO


United Nations Education Scientific and Cultural Organizatio

UNFCCC

United Nations Framework Convention on Climate Change

UN-REDD

UN- Reducing Emissions from Deforestation and Forest Degradation

UTM

Universal Transverse Mercator

USA

United States of America

USGS

United States Geological Survey

WGS

World Geodetic System

WRS

Worldwide Reference System


xvi


ACKNOWLEDGMENTS
First, I would like to express my sincerest thanks and appreciation to my supervisor
Professor. S.M.C.U.P. Subasinghe, Senior Lecturer of the Department of Forestry and
Environmental Sciences, University of Sri Jayewardenepura for his supervision and
valuable guidance throughout this project. His sincere technical advice and moral support
allowed me to complete this project in successful manner.
I am thankful to Associate Professor Vo Quang Minh, Head, Department of Land
Resources, College of Environment and Natural Resources, University of Can Tho,
Vietnam and Dr. Vo Quoc Tuan for their advices and suggestions on the field research
layout and for providing me the expertise knowledge on remote sensing and GIS techniques
during the early stages of this study.
I am thankful to the administrators of Lower U Minh National Park in Vietnam and
Department of Wildlife Conservation of Sri Lanka for their unlimited logistic support
during the field work.
I would like to express my sincere gratitude to all of the friends and colleagues in
Department of Forestry and Environmental Science, University of Sri Jayewardenepura for
their assistance and support during the field work.
I am thankful to the Ministry of Higher Education, Sri Lanka and Ministry of Education
and Training, Vietnam for their financial support for the study.
Last but not least I like to thank my wife Hong Ngoc and two children Tan Dat and Tan
Loc for their encouragement, patience and unlimited support to complete this study.

xvii


Investigation of Vegetation Structure and Carbon Storage in Lower U
Minh Wetland in Vietnam and Muthurajawela Wetland in Sri Lanka

by
PHAN TRUONG KHANH

ABSTRACT
This study conducted with Landsat Thematic mapper images and aerial photographs
combined with field data collection assessed the vegetation cover change over time in two
wetlands, i.e., lower U Minh national park in Vietnam for the years of 1975, 1995 and 2015
and Muthurajawela wetland in Sri Lanka for the years of 1992, 2001 and 2015. Vegetation
data collection and ground verification were conducted from April to October 2015 in the
lower U Minh national park using 45 sample plots of 40x40m and from June to December
2016 in Muthurajawela wetland using 36 plots. Both unsupervised and supervised
classifications were used to map the vegetation cover for two study areas.

However, maximum likelihood method of supervised classification showed better results
when compared with unsupervised classification for distinguishing vegetation classes in
both study areas. It identified six vegetation classes for both sites. Change of the classes of
vegetation cover classes in the lower U Minh national park is high mean. In contrast,
Muthurajawela wetland indicated a low change in the mangrove vegetation during the
study period. The analysis of this study proved that RS and GIS system approaches provide
useful baseline dataset on the changes of wetland vegetation over a time period. It therefore,
provides valuable information to aid the management and conservation of wetland habitats.

xviii


The results also showed that the average of density, height and DBH respectively were
528.65 trees/ha, 14.73±3.01 m and 17.17±7.05 cm for the natural M. cajuputi forest and
6,312.12 trees/ha, 11.45±2.25 m and 9.01±2.14 cm for the plantation forest of the lower U
Minh national park. The average green biomass of the natural M. cajuputi populations was
113.65 tons/ha (68.52 tons/ha dry) and that of for the plantation forest was 274.36 tons/ha

(179.16 tons/ha dry). The average carbon content of natural M. cajuputi forests was 56.18
tons/ha, which is equivalent to 206.18 tonsCO2/ha. The amount of carbon accumulated in
M. cajuputi population of the lower U Minh national park was 518,535.76 tons, which is
equivalent to 1,902,665.08 tons of CO2.

Bruguiera cylindrical, Rhizophora mucronata and Annona glabra were the dominated and
well-developed mangrove species in Muthurajawela wetland. R. mucronata had an average
density of 261 tree/ha, with the average height of 8.19±3.69 m, canopy cover of 5-7 m and
DBH of 9.54±2.87 cm. B. cylindrical population had the average density of 1,208.33
tree/ha, DBH of 9.05±3.95 cm and average height of 8.81±4.14 m. A. glabra which was
grown along the water canal had the average density of 1,375 tree/ha with an average height
of 6.50±2.29 m and DBH of 7.66±2.82 cm.

The average green biomass of B. cylindrical, A. glabra, R. Mcronata respectively were
31.56 kg/tree (equivalent to dry biomass of 17.36 kg/tree), 25.40 kg/tree (dry biomass of
13.44 kg/tree) and 36.76 kg/tree (dry biomass of 20.59 kg/tree). Other woody species had
the average green biomass of 34.24 kg/tree (dry biomass 18.45 kg/tree). The total aboveground biomass of the mangrove population in the Muthurajawela wetland was 447,357.48
tons (245,174.07 tons dry biomass), with their wealth of stored carbon of 115,231.81 tonsC
(22.05 tonsC/ha) which is equivalent 422,516.64 tonsCO2 (80.86 tonsCO2/ha).

xix