Commemorative lecture at Kyoto University, Nov. 2th 2008
and Tokyo University of Agriculture, Nov.7th 2008

Contents

Mangroves and Coastal Dwellers in
Vietnam - a Long and Hard Journey
Back to Harmony
Prof. Phan Nguyen Hong1

Introduction

2

Background of the Mangroves of Vietnam

3

Traditional Harmonious Co-existence ofMangroves & Coastal Dwellers

4

The Broken Harmony

5

The Long & Hard Journey to Re-establish the
Mangrove – People Harmony

6

Maintenance of the Harmony –Can Gio Case Study

12

Mangroves in the World
Mangroves of
Malaysia(Photo: IPT –Malaysia)

Background of theMangroves of Vietnam
A very dense roots system holds a 63-metre tall
Rhizophora mangle tree on mud at Limone,
Ecuador (photo: S. Baba)
A big Sonneratia
tree in New
Guinea (photo: S.
Baba)
Heritiera
liltoralis on
Iriomote island,
Japan (photo: J
Primavera)

Stunted mangroves on the
coast in the deserts of Arab
Saudi (photo: J.Primavera)

3

Mangroves in Vietnam

4

Geographical distribution
The different climatic andtopographical conditions along
the coast of Vietnam have deeply
affected the distribution andcomposition of mangroves.

•Ha Noi Capital- Coastline: 3,260km- Mangrove area:

 The four mangrove zones

T+ Before the wars: 408,500 ha+ In 1999

 The northeast zone

: 156,608 ha

Natural forests:

 The northern delta zone

38.10%

 The central zone

Replanted forests: 61.95%

 The coast of southern
Vietnam(FIPI, 2001)• HCM City

5

6

The northeast coastal zone (Quang Ninh Province)

The northern coastal delta zone (Red River Delta)

Natural conditions: Bai Tu Long and Ha Long Bays
 Diurnal tide, high amplitude
 Salinity: 26 - 27‰
 Cold northern monsoon
Plant communities
 Pioneer population: Avicennia marina
 Mixed community: A. marina, Rhizophorastylosa, Bruguiera gymnorrhiza, Kandelia
obovata Dominant B. gymnorrhiza
 Associate mangroves Large mudflat rich in alluvium &freshwater Subject to strong winds and storms,
cold in winterBrackish water communities
 Pioneer population: Sonneratia
caseolaris Mixed community of brackish water
species Community on the land rarely flooded
with normal tide

Bruguiera gymnorrhiza community

Sonneratia caseolaris community

Mixed true mangrove community

Community on the land rarely flooded

Kandelia obovata community

7

The central coastal zoneThe coast of southern Vietnam
 Favourable natural conditions
 No cold winter Abundant alluvium of Mekong and Dong Nai
Rivers Mangroves grow well and rich in composition

Short rivers
Rocky coastline
Strong waves
Mangroves distribute along estuaries
and river banks

 Avicennia marina-R.apiculata
communities
 Kandelia obovata & R.stylosa
communities. Associate mangrovecommunities.

8 Pioneer population: A. alba
Principal communities:
 R. apiculata + B. parviflora community R. apiculata + A. alba community Lumnitzera racemosa + Ceriops decandra
community Brackish water communities

7 year old Kandelia candel along the sea
dyke of Ha Tinh Province

Nipa palm at a river mouth

Mangroves along the river bank of Ngoc Hien
Dist., Ca Mau Prov.
Replanted
mangrovesin Can Gio,
Ho Chi
Minh City

Planted Rhizophora stylosa forest

9

10

Use of Products from Mangroves

Traditional Harmonious
Co-existence of Mangroves &Coastal Dwellers

Weavingmats fromsedge
A charcoal kiln in Ca Mau

Bee rearing in mangroves has
high economic benefits
Tannin from Rhizophora and Ceriops barks areused in cloth and net dying(Photo: M.Kogo)

11

Houses made from Rhizophora
timber and Nypa fruticans leaves

12Aquatic Resources

The Broken Harmony
Litter fall - an important source oforganic detritus

Many fishermen earn their livingusing nets and lights on canals inmangrove

Mudskipper catching
Poor women digging shellfish on tidal mudflat

14

13

Chemical Warfare

Mangroves Destroyed by Chemical Spraying in Ca Mau
Map of the mangroves on the
tip of Ca Mau Peinsula,
Minh Hai Prov. in 1972,
showing areas bare fromherbicide spraying (Source:
NAS, 1974)

A trace of mangrove land sprayedby herbicides and the remain(right)

The dead trees fell on the sprayed area
Rung Sat area
sprayed withwarring herbicides
in 1969(photo: E.W.
Pfeiffer)

Mangrove forest at Ca Mau
Cape before the chemical
war

Mature mangrove forest in Ca Mau Cape
totally destroyed by herbicides (Photo:
Phan Nguyen Hong)

Photo: Minh Hai Museum

15Over-exploitation

Mangroves Destroyed by Chemical Spraying in Can Gio

Mangroves at Con Den Island, Thai Binh
Province were cut down by local people forfirewood, resulting in heavy erosion of the coast

Four fixed wing
UC-123 aircraft
on a spraymissionOver
exploitation ofmangroves in
Ca MauPhoto: Harold C.
Kinne, Jr.

Map ofmangroves in
the post-war(left)

16

Mangroves in Rung Sat, Can Gio, Ho Chi Minh
before being sprayed with warring herbicides(photo: E.W. Pfeiffer)(Source: Hirose,
ASTER remotesensing)

Men laugh mangrove treescry!!

A part of Rung Sat
was being sprayedwith herbicides(photo: E.W.
Pfeiffer)

17

18

The map of mangrove forests in Ca Mau Capebefore herbicide spraying (1961)
Forest: 95.7 %Non forest :4.3%

Conversion of Mangroves to Shrimp Ponds: Ca Mau Prov.
Mangroves of
Ca Mau before
the conversion
to shrimp pond

1965

Shrimp ponds

2001

Mangroveforests

About 2/3 of mangroves in Ca Mau
were converted to shrimp ponds

Mangrovesof Ca Mau
at thepresent

Year

Mangrovearea (ha)Shrimppond (ha)1961

150,000

0

1999

58,25892,000

Most part ofmangrove forests
were converted
to shrimp ponds(Spot image in2001 (F.Blasco))

Source: Populus et al., 200420

19

Photo: Le Cong Kiet

Cam Ranh , Khanh Hoa Prov.

Tra Vinh & Ben Tre Provinces – Decrease in Mangrove Areas

1965 – 36,276 ha
1960

East Sea

1965 - 21,221 ha dense
forests

Mangroves in the west of Cam Ranh Peninsula (1960)
LegendRoad
River
Boundary ofstudied area

East Sea

Source: Ngo An, 2003
2001 - 4,131 ha planted forests
2000 - 7.153 ha

Source: Populus et al., 2004

Source: Lê Công Kiệt, 1961

All mangrove areas have been converted to shrimp ponds (1994)

22

21

Environment Impacts of Shrimp Culture

Yen Hung, Quang Ninh Prov.

1965
10,107 ha
All mangroves trees died after
long time being inundated in
shrimp ponds

1998
2,969 haSource: Vu Trung Tang,
Nguyen Thi Kim Cuc,1999

Painting: T¹ LùuConversion ofmangroves toshrimp ponds“Please rescue our friend fromwater asphyxiation”

23

24

Environmental Pollution

Conversion of Mangroves to Other Uses

Inside the pond, muddy soil turning black,benthos were killed

Salt pans converted from mangroves
produce poor quality salt

Agricultural fields converted from mangroves
have now become fallow

Water pollution due to shrimp culture

Outside the pond, alluvial soil is still good
(Ngoc Hien – Ca Mau)

Mangroves along Da Bach river – Uong Bi
have been destroyed to build a coal port

Nam Can Town built on a former
mangrove area

25

26

Other Impacts of the Loss of Mangroves

The Long & Hard Journey
to Re-establish
the Mangrove – People Harmony
Severe erosion along river banks

MANGROVE REFORESTATION – THE FIRSTSTEP Post-war period (1975-1980)
 From 1981 to 1990
 From the 1990s to dateThis house had to be moved 3 times
due to riverbank erosion

27

28

Reforestation on the Areas Sprayed by Herbicides

Mangrove Rehabilitation Under State Programs

The area of mangroves rehabilitatedfrom 1975 to 1980 on the land sprayedwith warring herbicides
Province
Ben TreLocal people replanting Rhizophora apiculata on thearea sprayed with herbicides in Ca Mau Cape (1975)

Women replanting
mangroves (1978)

Area (ha)10,470Tra Vinh

3,990

Soc Trang

1,750

Minh Hai (Ca Mau+Bac Lieu)

25,900

Dong Nai

4,100

HCM City

6,240

Total

52,450

Women of Can Gio preparing
Rhizophora propagules forreforestation (1978)

29

Rehabilitated Areas in Some Coastal Provinces in the 1990s
No

Province

Area funded by State
programs (ha)No

Province

Area funded by State
programs (ha)1

Hai Phong234

2Thai Binh

1399

3

Nghe An

563

8

Ben Tre1200

9

Tra Vinh

4137

10

Soc Trang

4

Ha Tinh46

11

Bac Lieu

1404
716

5

Ba Ria-Vung Tau

3615

12

Ca Mau18500

6

Ho Chi Minh City

20636

Total

52913

7

Tien Giang

463

Eight year old
Rhizophora
apiculata at Ca
Mau Province

Four year old
Kandelia obovata
forest at Nam Dinh
Province30

Rehabilitation Projects Supported By Foreign NGOs

Rehabilitation Projects Supported By Foreign NGOs
Save the Children Fund UK

ACTMANG - TOKIO MARINE ProjectSpecies: Kandelia obovata, Avicennia marina,
Rhizophora stylosa
Planting duration: 1991-1994, Area: 321 ha
Five years after K. candel planting
Avicennia marina strongly regenerated(middle)Danish Red Cross (DRC) Projects in Thai Binh and Nam Dinh Provinces
Species: Kandelia candel, Sonneratia caseolaris, Rhizophora stylosa
Planting duration: 1994-2002, Area: 6,912 ha

Planted Sonneratia caseolaris forest at
Tien Lang Distr. Hai Phong City

Japanese Red Cross (JRC) Project

PlantedSonneratia
caseolarisforest inThai Binh

PlantedKandelia
obovata
mixed with
Rhizophorastylosa in
Nam Dinh

Species: K .obovata,
S. caseolaris,
Rhizophora stylosa,
Bruguiera
gymnorhiza
Planting duration:
1994-2007,
Planted Rhizophora stylosa at Tinh Gia
Provinces: 8
Area: 1,500 ha

Species : Kandelia
obovata, Sonneratia
caseolaris
Provinces: 6
Planting duration:
1997-2005
Area : 5,685ha

8 month old Kandelia obovata at Kien
Thuy Dist., Hai Phong City

32

31

World Bank Mangrove Planting Project

Mangrove Restoration at Can Gio

Prov.: Ca Mau, Soc Trang, Ben Tre, Tra Vinh
Planting duration : 2000 – 2005; Area : 3648ha

Remote sensing map
on the statusof mangroves at Can Gio
Biosphere Reserve

Forest land
 Replanted forest Natural forest
Total : 71,361 ha

33,385 ha
21,427 ha
8,958 ha42.58%
30.03%
12.55%
100%

4 year old of Sonneratia at Trung Binh
Commune, Soc Trang Prov.
1 year old S. caseolaris at Long Hoa
Commune, Tra Vinh Prov.

1 year old Rhizophora apiculata at Vinh
Chau Dist., Soc Trang Prov.

4 year old S. caseolaris at My Long Nam
Commune, Tra Vinh Prov.

Source: K. Hirose, ERSDAC

34

33

Enhanced Biodiversity

Flora and faunal species in the Can Gio Mangrove Ecosystem

Nature’s ResponsetoPeople’s Efforts

BiologicalgroupsSpecies

Families

PlantsSpecies

Families

Vertebrates

True m. sp.

32

15

Fish

133

40

Associate m.
sp.

42

29

Amphibia

94Inland plants

120

45

Invertebrates

35

BiologicalgroupsPolychaeta

32

18

Crustacea

53

11

Mollusca

32

15

Reptiles

31

15

Aves

130

41

Mammal19

13

36

Some True Mangrove Species
Bruguiera
parviflora

Sonneratia
caseolaris

Rhizophora
apiculata

Two Species Recently Found in Vietnam
Avicennia
alba

Rhizophora lamarkii

Bruguiera exaristata Ding Hou

38

37

The Vegetation

The Fauna

Cerithidea cungulata

Invertebrate: 117 sp.

Clams

Vertebrate: 222 sp.
Blood cockles
Spot-tail mantis
shrimp10 year old planted Rhizophora
apiculata population

Horseshoe crabs

Rhizophora andAvicennia
community
Planted Rhizophora and wild
Acrostichum community

Areolate grouper

Green snake

39

40

Aquatic Resources
Clam harvest on
the mud flat infront ofmangrove area
Eurasian otter

Wild pig

Fish in mangroves(Photo M.Yokotsuka)

A popular uca inmangroves

Spot-billed pelican
Fish-eating cat

Sciena sp., a very valuable fish caught at the rivermouth in newly planted mangroves of Thai Binh
Province. Its air bladder is used to make thread forsome special operations. The price of each air bladderis 10,000 - 20, 000 USD.

Water monitor
Long-tailed Macaque

41

Bostrichthys
sinensis42

Avifauna

Effects of Reforestation on the Environment

Bird sanctuary of Ca Mau Cape NP-Provision of a buffer
against waves and
CHARACTERISTICS

limiting of erosion- Protection of the banksof aquaculture ponds- Protection of coastal works- Aerial root system- Strong trunk

Painted Stork, Grey Heronand Litle Egret- Large foliage- Protection of alluvia- Rapid growth- Continent extension- Creating: new land (islands)-Ability to tolerate waves
and wind-Ability to tolerate long-timeinundation- Protection of sea dykes- Mitigation of the damage
caused by storms and sea
level riseBlack-tailed Godwit

43

44

Reduction of Storm Waves by Replanted Mangroves

Wave Reduction by Planted Mangroves

Storm Waley (31/7/2005): 98 – 102 km/h

Impacts of the difference of wave
reduction between an area with
mangroves (a) and an area withoutmangroves (b) at Thuy Hai – Thai Binh
- Where there is a mangrove forest 1.5
km in width, 1-m waves from the plantedsite were reduced to 0.05m height whenreaching the crab pond
- Where there is no mangrove forest,with the same distance, the wave height at
the crab pond was 0.75 m and the pondbank was eroded.
Source: Mazda et al.,The area behind Bang La Mangroves at 9h30,
31/7/2005 remained intact

Storm Waley hit Hai Phong sea dyke

The area behind Bang La Mangroves at 12h45,
Sea dyke broken at Cat Hai where there
31/7/2005
were no mangroves
Photo: Vu Doan Thai

45

Wave Height Reduction thanks to Mangroves

46

Storm Damrey (27/9/2005): 118 – 133 km/h

during Storm Waley (31/7/2005)
The concrete dyke in Do Son – Hai Phong
was destroyed by storm

h(m)
1.60
Tr-í c rõngSau rõng

1.20
1.00
0.80
0.60
0.40
0.20
giê
1 4 :0 0 :0 0

1 3 :3 0 :0 0

1 3 :0 0 :0 0

1 2 :3 0 :0 0

1 2 :0 0 :0 0

1 1 :3 0 :0 0

1 1 :0 0 :0 0

1 0 :3 0 :0 0

1 0 :0 0 :0 0

0.00

Wave height in front and 650m
behind Kandelia.obovata forest at
Bàng La, Hai Phong City –average reduction factor 80%

H (m)
1,80
1,60
1,40
1,20
1,00
0,80
0,60
0,40
0,20
0,00

In front of forest
Behind forest

10:0
10 0 :0:1 0
10 5 :0:3 0
10 0 :0:4 0
11 5 :0:0 0
11 0 :0:1 0
11 5 :0:3 0
11 0 :0:4 0
12 5 :0:0 0
12 0 :0:1 0
12 5 :0:3 0
12 0 :0:4 0
13 5 :0:0 0
13 0 :0:1 0
13 5 :0:3 0
13 0 :0:4 0
14 5 :0
:0 0
0:
00

1.40

Time

Wave height in front and 920 m behind Sonneratia
forest at Tien Lang Dist., Hai Phong City Behind Bang La Mangroves, Hai Phong,the waves were strongly reduced

average reduction factor of 78%

Photo: Vu Doan Thai

47

48

Wave Height Reduction thanks to Mangroves
during Storm Damrey (27 Sep 2005), 118-133km/h

Storm Xangsane (1/10/2006)
Houses and trees in Vung Tau City were broken, in contrast, Can Gio mangroves
successfully protected the communities

h(m)
1.60

Tr- í c rõng1.40

Sau rõng

Can Gio District

1.20
1,6

1.00

1,4

0.80
0.60

1,2
1

0.40

0,8

H (m)

In front of forest
Behind forest

0,6

0.00
1 2 :3 0 :0 0

1 2 :0 0 :0 0

1 1 :3 0 :0 0

1 1 :0 0 :0 0

9 :3 0 :0 0

1 0 :3 0 :0 0

9 :0 0 :0 0

1 0 :0 0 :0 0

8 :3 0 :0 0

8 :0 0 :0 0giê

Wave height before and after 650m K.obovata forest
Average reduction factor 87%

0,4
0,2

Vung Tau City

0
Hour

8:
30
:0
0
9:
00
:0
0
9:
30
:0
0
10
:0
0:
00
10
:3
0:
00
11
:0
0:
00
11
:3
0:
00
12
:0
0:
00
12
:3
0:
00

0.20

Wave height before and after 920m ofSonneratia caseolaris forest
Average reduction factor 81%

49

50

Mangrove Micro-organisms – A Valuable Gift

Expansion of Alluvium Soils and Restriction of Erosion

Microorganisms
decomposing
wastesBacteria

Ca Mau Cape mud flat

Xuan Thuy Ramsar site

Seawater cleaning

Mangrove micro-organisms
storing and decomposing wastes
into nutrients

Yeast

Filamentous fungi

Waste
decomposition
Food for tidal organisms

Actinomycetes

Can Gio Mangrove Biosphere Reserve

Trees in inland areas, after the storm in 2003 in
Nam Dinh, being trapped by mangrove forests

Solid wastes discharged by production and daily
activities moved to mangroves and were broken
down into food for tidal organisms

51

Mangroves Cleaning Water and Protecting Coral
Reefs and Sea-grasses

52

Increased Aquatic Resources

Replanted mangroves enhancing aquatic resources
especially seed crabs and benthos(Source: McLeod and Salm, 2006)

53

Painting: Ta Luu

54

Catching Aquatic Resources – the Livelihood of Poor
Coastal Dwellers

Side-line Jobs for Poor Households

On the way to catchaquatic products

Handicraft: weaving of nipa palm leaves(photo: L.K.Thoa)

Stimulating
nipa fruitbunch toextract sap forsoft drink

The new house of one poor
household living on catchingaquatic resources
Thinned timber is very good for housebuilding

Digging for sea crabs

56

55

Eco-tourism – a New Source of Income

Can Gio Resort

Macaques

57

58

Ca Mau Cape National Park
Watching crocodiles

New road in the planted
mangrove

Ca Mau Cape National Park

Visiting resistance baseTourist area
Bird sanctuary

5960

Xuan Thuy Ramsar Site

Scientific ResearchVietnamese and Japanese scientists studying the
growth of mangrove trees

Students of Ho Chi Minh City studying
mangrove flora

Japanese scientists
studying physicalprocesses inmangrove areas

61

62

Students’ Camping and Educational Excursions

Scientific Research

Japanese students participating inmangrove plantation

Studying structureof mixed forests in
Can Gio mangrove
forestStudents watching monkeys

Scientists
studying
biomass of
Avicennia alba
forestJapanese and Vietnamesescientists studying mangrove
soil in Can Gio (photo:
P.N.Hong)

64

63

Raising Awareness of Students and Communities

Public Education on Mangrove Protection- the Next Step

65

66

National Symposium “Mangrove Restoration For Climate Change
Adaptation And Sustainable Development” – Can Gio, 26-27/11/2007

Educational and Promotional Activities
Training courses for local communities and local
management staff
Mobile exhibition “For the Green of Mangroves”
Study visits to MERS for secondary school
students in coastal mangrove areas
Mangrove knowledge quizzes
Educational activities for the wholecommunity

Symposium presidium

Overview of the meeting hall

Participants learning about
the life of forest guards

Visiting Can Gio
Mangrove Museum
Training course for teachers of
biology in coastal area

Training students on environmental
knowledge at Mangrove Ecosystem
Research Station (MERS)

Training course for local
officials at MERS

67

68

Policies for Mangrove Protection
 City leaders have created favorable materialand spiritual conditions for local households inlong-term mangrove caring and protection:

Maintenance of the Harmony:
Can Gio Case Study Select poor households with labor force
 Provide payment for house building in forests, and internal furniture Provide boats
Yearly increase in payment for forest Provide fresh water
protection (%)
 Grant scholarship to their children
445000 Increase gradually the payment
700
316000600
for forest guardsÎStable life, secure
feelings

500
400
300
200
100
0

185000
70000

1980

1985

1990

2006

Year

69

Discussion on selection of forest guard households andestablishment of a supporting group for forest protection

70

Guard Households Living in Harmony with Mangroves

Group offarmers
discussing
forestallocation forprotection
purposeCockle rearing
areas

House of a forest guard
household
Meeting of forest guard households

Meeting of
the Steering
Board onforestprotection
Crab pond of a forest
guard household

Meeting of forest protection staff on coordination
with forest guard households

7172Additional Income for Forest Guard Households

Can Gio Biosphere Reserve – Our PrideGoat raisingBlue dragon cultivation

Pig raising

73

74

Welcome Japanese students and scientists
to Vietnam and our mangroves!

For more information, please contact me at:
Email: hongrnm@yahoo.com.vn
Tel:+84 48 438 4927576