The Effects Of Timber Logging On Stand Structure And Species Composition In North Zamayi Reserver Forest Tharyarwddy District Myanma

MINISTRY OF EDUCATION AND

TRAINING

MINISTRY OF AGRICULTURE AND

RURAL DEVELOPMENT

VIETNAM NATIONAL UNIVERSITY OF FORESTRY

--------------------

MYO MIN THANT

THE EFFECTS OF TIMBER LOGGING ON STAND

STRUCTURE AND SPECIES COMPOSITION IN NORTH

ZAMAYI RESERVE FOREST, THARYARWADDY

DISTRICT, MYANMAR

MASTER THESIS IN FOREST SCIENCE

Hanoi, 2018

MINISTRY OF EDUCATION AND

TRAINING

MINISTRY OF AGRICULTURE AND RURAL

DEVELOPMENT

VIETNAM NATIONAL UNIVERSITY OF FORESTRY

--------------------

MYO MIN THANT

THE EFFECTS OF TIMBER LOGGING ON STAND

STRUCTURE AND SPECIES COMPOSITION IN NORTH

ZAMAYI RESERVE FOREST, THARYARWADDY

DISTRICT, MYANMAR

Major: Forest Science

Code: 8620201

MASTER THESIS IN FOREST SCIENCE

Signature: ………………………….

Supervisor: Dr. MANH HUNG BUI

Hanoi, 2018

i

Abstract

Natural forests in Myanmar are being managed based on sustainable forest

management principle; under a regulation of Myanmar Selection System (MSS) since

1856. Notwithstanding the hundreds years of its reputation of good forest management and

timbers that stand firmly as the essence of gross national proceeds, concerns over the long￾standing practice of MSS is widely debated in term of sustainability when after the

production forests were adversely threatened by degradation. Although the mixed

deciduous forests in Myanmar are renowned as legendary of teak bearing forests, the

impact of selective logging, which has conducted annually over centuries, remains

unknown. Therefore, it needs the hands of the people, especially foresters and researchers.

Through research, scientists can provide the knowledge and understanding of the forest,

including the structure and forest restoration.

This study was conducted at NZRF, Tharyarwaddy, Myanmar to evaluate the

change of floristic characteristics, structure and regeneration potential of teak bearing

forest in Bago region after selective logging in order to contribute the scientific findings to

improve the silvicultural system applied to sustainable forest management in this region.

The evaluation based on data collected from one hectare of each forest types; forests after

10 years and 20 years of selective logging, in representative for two harvested sites in

comparison with new data collected from one hectare of old-growth forest nearby as a

control. This study has obtained important findings. Results show that, selective logging

forests have been changed in all floristic characteristics, structure and regeneration

potential in comparison with primary forest and between two harvested sites. In floristic

characteristics, this change is clear in species richness, species composition and species

similarity. The secondary forest is more homogeneous and uniform, while the old-growth

forest is very diverse. While in stand structure, the change is clear vertical and horizontal

structure, diameter distribution, stand density, basal area, stock volume and volume

increment. Biodiversity of the overstorey in the secondary forest is more than the primary.

Density of regeneration is also shown a different between old-growth forest and

harvested forest, between harvested forest sites. The secondary forest still has mother trees

and sufficient regeneration, so some restoration measures can be applied here. Findings of

the study contribute to improve people’s understanding of the structure and the structural

ii

changes after harvesting in NZRF. That is a key to have better understandings of the

history and values of the forests. These findings and the proposed restoration measures

address rescuing degraded forests in Bago region in particular and Myanmar in general.

And further, this is a promising basis for the management and sustainable use of forest

resources in the future.

Keywords: NZRF, Myanmar Selection System, reserve forest, natural regeneration,

stand structure, species diversity, sustainable forest management.

iii

CONTENTS

Abstract ……………...………………………………………………………………i

List of Figure ...…………….……….………………………………………………vi

List of Table ………………...………………………………….…………………viii

Abbreviation ………………………………………………………………………...x

CHAPTER I. Introduction ..........................................................................................1

1.1. Background Information ...................................................................................1

1.2. The state of Forest in Myanmar.........................................................................3

1.3. Myanmar Selection System...............................................................................5

1.4. Problem Statement.............................................................................................8

1.5. Objectives and research questions of the study.................................................9

1.5.1. General Objectives.........................................................................................9

1.5.2. Specific Objectives.........................................................................................9

CHAPTER II. Literature Review..............................................................................10

2.1. Tropical forest in the world .............................................................................10

2.2. Deforestation ...................................................................................................12

2.2.1. Major causes of deforestation ......................................................................13

2.3. Tropical mixed deciduous forest in Myanmar.................................................14

2.4. Deforestation and forest degradation in Myanmar..........................................16

2.5. Review of AAC for timber harvesting in Myanmar........................................18

2.6. Sustainable tropical forest management..........................................................19

2.7. Silvicultrual management system of tropical forests ......................................20

2.8. Stand structure, species dynamic and natural regeneration in natural forest ..22

iv

CHAPTER III. Materials ..........................................................................................24

3.1. General description of study site .....................................................................24

3.1.1. Topography ..................................................................................................25

3.1.2. Climate .........................................................................................................26

3.1.3. History of silvicultural and forest management practices in the study site..28

CHAPTER IV. Methodology....................................................................................29

4.1. Establishment of permanent sample plots/ sampling design...........................29

4.2. Data collection method....................................................................................31

4.2.1. Tree data collection ......................................................................................31

4.2.2. Coordinate of the tree ...................................................................................32

4.2.3. Data collection for regeneration...................................................................33

4.3. Data analysis method.......................................................................................34

4.3.1. Stand Information.........................................................................................34

4.3.2. Descriptive statistics for height and diameter variables...............................35

4.3.3. Linear mixed-effects analysis.......................................................................38

4.3.4. Frequency distributions................................................................................38

4.3.5. Diameter-height regression analysis ............................................................40

4.3.6. Spatial point patterns of tree species............................................................41

4.3.7. Tree species composition analysis results....................................................41

4.3.8. Regeneration storey structure analysis.........................................................44

CHAPTER V. Results and Discussion .....................................................................45

5.1. Stand information ............................................................................................45

5.2. Descriptive statistics results ............................................................................48

5.2.1. Vertical and horizontal projections ..............................................................51

5.3. Linear mixed effect model results...................................................................53

5.4. Frequency distributions ...................................................................................55

5.5. Diameter-height regression results..................................................................63

5.6. Spatial distribution analysis.............................................................................66

v

5.6.1. Density testing results ..................................................................................66

5.6.2. Spatial distribution pattern testing................................................................70

5.7. Tree species composition analysis results.......................................................74

5.7.1. Family composition......................................................................................74

5.7.2. Species composition.....................................................................................77

5.7.3. Species similarity .........................................................................................79

5.7.4. Species Diversity..........................................................................................81

5.8. Regeneration storey structure analysis results.................................................82

5.8.1. Height frequency distribution.......................................................................82

5.8.2. Biodiversity index for regeneration..............................................................87

5.9. Silvicultural approaches for SFM in the North Zamayi RF ............................90

CHAPTER VI. Conclusion .......................................................................................93

ACKNOWLEDGEMENT ........................................................................................96

REFERRENCES.......................................................................................................97

APPENDIX ………………………………………………………………………105

vi

LISTS OF FIGURE

FIGURE 2.1: FOREST COVERS AT DIFFERENT PERIODS IN MYANMAR.............16

FIGURE 2.2: TREND OF CHANGES IN ‘OPEN FOREST’ TO ‘CLOSED FOREST’ IN

MYANMAR.................................................................................................................17

FIGURE 2.3: CHANGE OF AAC FOR TEAK (TECTONA GRANDIS) OVER 1995 TO

2011 AT COUNTRY LEVEL......................................................................................18

FIGURE 2.4: CHANGE OF AAC FOR HARDWOOD SPECIES OVER 1995 TO 2011

AT COUNTRY LEVEL...............................................................................................18

FIGURE 2.5: NATIONAL INCOME FROM TIMBER EXPORT DURING 2000 TO 2012

......................................................................................................................................19

FIGURE 3.1: LOCATION OF NORTH ZAMAYI RESERVE FOREST..........................25

FIGURE 3.2: CLIMATE DIAGRAM OF NORTH ZAMAYI RESERVE NEAR

THARYARWADDY TOWNSHIP; DATA RECORDED FROM 2008 TO 2017

(METROLOGICAL DEPARTMENT, THARYARWADDY TOWNSHIP)..............28

FIGURE 4.1: THREE DIFFERENT KINDS OF FOREST IN NZRF................................29

FIGURE 4.2: SAMPLE PLOT............................................................................................30

FIGURE 4.3: MEASURING POSITION OF DBH ............................................................31

FIGURE 4.4: DIAMETER MEASUREMENT BY USING A DIAMETER TAPE ..........32

FIGURE 4.5: HEIGHT MEASUREMENT BY USING A BLUE-LEISS .........................32

FIGURE 4.6: SUB-PLOTS FOR MEASURING TREE POSITION..................................33

FIGURE 4.7: REGENERATING TREE INVESTIGATION .............................................33

FIGURE 5.1: VERTICAL AND HORIZONTAL PROJECTIONS FOR ALL FOREST

TYPES..........................................................................................................................51

FIGURE 5.2: DIAMETER FREQUENCY DISTRIBUTION GRAPHS FOR OLD

GROWTH FOREST.....................................................................................................56

FIGURE 5.3: DIAMETER FREQUENCY DISTRIBUTION GRAPHS FOR 20 YEARS

AFTER LOGGING FOREST ......................................................................................57

FIGURE 5.4: DIAMETER FREQUENCY DISTRIBUTION GRAPHS FOR 10 YEARS

AFTER LOGGING FOREST ......................................................................................58

vii

FIGURE 5.5: HEIGHT FREQUENCY DISTRIBUTION GRAPHS FOR OLD GROWTH

FOREST .......................................................................................................................60

FIGURE 5.6: HEIGHT FREQUENCY DISTRIBUTION GRAPHS FOR 20 YEARS

AFTER LOGGING FOREST ......................................................................................61

FIGURE 5.7: HEIGHT FREQUENCY DISTRIBUTION GRAPHS FOR 10 YEARS

AFTER LOGGING FOREST ......................................................................................62

FIGURE 5.8: THE HEIGHT AND DBH RELATIONSHIP OF ALL STEMS WITH A

DBH≥ 6 CM OF OLD GROWTH FOREST IN NZRF ...............................................64

FIGURE 5.9: THE HEIGHT AND DBH RELATIONSHIP OF ALL STEMS WITH A

DBH ≥ 6 CM OF FOREST (AFTER 20 YEAR LOGGING) IN NZRF .....................64

FIGURE 5.10: THE HEIGHT AND DBH RELATIONSHIP OF ALL STEMS WITH A

DBH≥ 6 CM OF DEGRADED FOREST (AFTER 10 YEAR LOGGING) IN NZRF65

FIGURE 5.11: TREE POSITION ON THE GROUND OF OLD GROWTH ....................67

FIGURE 5.12: TREE POSITION ON THE GROUND AFTER 20 YEARS OF LOGGING

......................................................................................................................................68

FIGURE 5.13: TREE POSITION ON THE GROUND AFTER 10 YEARS OF LOGGING

......................................................................................................................................69

FIGURE 5.14: DENSITY DISTRIBUTION.......................................................................70

FIGURE 5.15: THE PAIR CORRELATION FUNCTION RESULTS OF OLD-GROWTH

......................................................................................................................................71

FIGURE 5.16: THE PAIR CORRELATION FUNCTION RESULTS OF 20 YEARS

AFTER HARVESTING...............................................................................................72

FIGURE 5.17: THE PAIR CORRELATION FUNCTION RESULTS OF 10 YEARS

AFTER HARVESTING...............................................................................................73

FIGURE 5.18: REGENERATION HEIGHT FREQUENCY DISTRIBUTION FOR OLD

GROWTH FOREST.....................................................................................................83

FIGURE 5.19: REGENERATION HEIGHT FREQUENCY DISTRIBUTION FOR 20

YEARS AFTER LOGGING FOREST ........................................................................84

FIGURE 5.20: REGENERATION HEIGHT FREQUENCY DISTRIBUTION FOR 10

YEARS AFTER LOGGING FOREST ........................................................................85

FIGURE 5.21: REGENERATION SPECIES ACCUMULATION CURVES ...................88

viii

LISTS OF TABLE

TABLE 1.1: STATUS OF PERMANENT FOREST ESTATE............................................5

TABLE 3.1: MONTHLY MEAN RAINFALL AND TEMPERATURE (2008-2017) AND

DE MARTONNE’S ARIDITY INDEX FOR THARYARWADDY TOWNSHIP,

2018. .............................................................................................................................27

TABLE 4.1: MEASURE OF DISPERSION AND VARIABILITY...................................36

TABLE 4.2: EQUATIONS USED FOR REGRESSION....................................................40

TABLE5.1: STAND INFORMATION FOR PLOTS .........................................................46

TABLE 5.2: DESCRIPTIVE STATISTICS FOR DIAMETER VARIABLE....................49

TABLE 5.3: DESCRIPTIVE STATISTICS FOR HEIGHT VARIABLE..........................52

TABLE 5.4: LINEAR MIXED EFFECT MODEL FOR DBH...........................................53

TABLE 5.5: LINEAR MIXED EFFECT MODEL FOR H ................................................54

TABLE 5.6: MOST IMPORTANT FAMILIES OF THE OLD GROWTH FOREST OF

NZRF (ALL STEMS WITH A DBH ≥ 6CM). ............................................................75

TABLE 5.7: MOST IMPORTANT FAMILIES OF THE 20 YEARS AFTER LOGGING

FOREST OF NZRF (ALL STEMS WITH A DBH ≥ 6CM). ......................................75

TABLE 5.8: MOST IMPORTANT FAMILIES OF THE 10 YEARS AFTER LOGGING

FOREST OF NZRF (ALL STEMS WITH A DBH ≥ 6CM). ......................................76

TABLE 5.9: MOST IMPORTANT SPECIES OF THE OLD GROWTH FOREST OF

NZRF (ALL STEMS WITH A DBH ≥ 6CM). ............................................................77

TABLE 5.10: MOST IMPORTANT SPECIES OF THE 20 YEARS AFTER LOGGING

FOREST OF NZRF (ALL STEMS WITH A DBH ≥ 6CM). ......................................78

TABLE 5.11: MOST IMPORTANT SPECIES OF THE 10 YEARS AFTER LOGGING

FOREST OF NZRF (ALL STEMS WITH A DBH ≥ 6CM). ......................................78

TABLE 5.12: THE SIMILARITY COEFFICIENT (KD) AMONG THE DIFFERENT

FOREST TYPES (ALL STEMS WITH A DBH ≥ 6CM) IN NZRF. ..........................80

TABLE 5.13: DIVERSITY INDICES (SIMPSON, SHANNON-WEINER, AND

EVENNESS) OF THREE DIFFERENT FOREST TYPES OF NZRF (ALL STEMS

WITH A DBH ≥ 6CM).................................................................................................81

ix

TABLE 5.14: SPECIES DIVERSITY FOR REGENERATION OF OLD GROWTH

FOREST .......................................................................................................................87

TABLE 5.15: SPECIES DIVERSITY FOR REGENERATION OF 20 YEARS AFTER

LOGGING FOREST....................................................................................................87

TABLE 5.16: SPECIES DIVERSITY FOR REGENERATION OF 10 YEARS AFTER

LOGGING FOREST....................................................................................................88

x

ABBREVIATION

AAC = Annual Allowable Cut

FAO = Food and Agriculture Organization of United Nations

FD = Forest Department

Ha = hectare

km2 = Square kilometer

cm = centimeter

MTE = Myanmar Timber Enterprise

MUMD = Moist Upper Mixed Deciduous Forest

WC = Plantation Working Circle

RF = Reserve Forest

RIL = Reduced Impact Logging