THAI NGUYEN UNIVERSITY
UNIVERSITY OF EDUCATION

HOANG VAN HAI

STUDY SOME BASIC CHARACTERISTICS AND PROPOSE
MEASURES TO CONSERVE AND DEVELOP SUSTAINABLY
THE VEGETATION ON LIMESTONE MOUNTAIN AREA IN
CAM PHA CITY, QUANG NINH PROVINCE

Speciality: Ecology
Code: 9420120

DISSERTATION SUMMARY

THAI NGUYEN - 2019


The dissertation was finished at:
THAI NGUYEN UNIVERSITY - UNIVERSITY OF EDUCATION

Supervisors:
1. Assoc. Prof. Ph.D Nguyen The Hung
2. Assoc. Prof. Ph.D Le Ngoc Cong

Reviewer 1:………………………………………………

Reviewer 2:………………………………………………

Reviewer 3:……………………………………………….


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PREAMBLE
1. The urgency of the thesis
Cam Pha city with Bai Tu Long Bay (buffer zone of Ha Long Bay)
is one of Quang Ninh's tourism areas, currently limestone mountain
vegetation is being degraded in both area and quality due to some
causes such as exploiting plant resources used as firewood, limestone
exploitation for the industry of construction material production,
encroaching on sea, expanding residential land fund ...
To contribute to improving the effectiveness of management,
conservation and sustainable development of vegetation on limestone
mountains in Cam Pha city, Quang Ninh province, the thesis "Study
some basic characteristics and propose measures to conserve and
develop sustainably the vegetation on limestone mountain area in
Cam Pha city area, Quang Ninh province ” was performed.
2. Objectives of the study
Determining the basic characteristics of vegetation on limestone
mountains in Cam Pha city area, Quang Ninh province. Proposing the
directions of reasonable use and protection, meeting economic, social
and environmental development needs.
3. The meaning of the thesis
Quantifying the structural characteristics and growth capacity of
timber trees in the vegetation on limestone mountains in Cam Pha city,
Quang Ninh province. The research results are the basis to orient
conservation solutions in order to sustainably develop the vegetation on
limestone mountains in Cam Pha city.
4. New contributions of the thesis
- In terms of theory: Provide scientific data on species composition,
structural characteristics, geographical factors, growth and regeneration
capacity of woody trees, and the distribution of the vegetation on

diameter of woody trees in vegetation on limestone mountains.
1.1.2. Studies on the vegetation on limestone mountain in the country
In Vietnam, the majority of limestone mountains and limestone
forest and mountains concentrate mainly in the provinces of the
Northeast, Northwest and North Central regions with a total of
1,152,200 ha, limestone mountains account for only 3.5 % of the
natural area in the whole country and distributed in the following areas:
North West 229,100 ha; Northeast 638,900 ha; Northern Delta 19,200
ha; North Central Region 246,800 ha; Central Coast 3,800 ha; Central
Highlands 8,400 ha; Southeast 600 ha; Mekong Delta 300 ha.
On the basis of referring to the research results of 15 domestic
authors, the thesis has synthesized the research results related to this
work: (1) Determining the composition of plant species on limestone
mountains; (2) Determination of vegetation type; (3) Determine the
group of plants on limestone mountains; (4) Determine the structure of
D1.3 and Hvn; (5) Evaluate the regeneration capacity of woody trees.
Most authors in the country only study the vegetation on limestone
mountains in mainland. Some authors have also published researches
on the vegetation on limestone mountains in the sea, however, those


3
only aimed at the determination of plant species composition, but not
research deeply on vegetation structure.
1.2. Studies on the vegetation on limestone mountains in Quang
Ninh province
There are very few authors studying the vegetation on limestone
mountains in Quang Ninh province. Of them, the research performed
by Nguyen Tien Hiep (2005) and reported in the "Proceedings of the
conference on biodiversity of Ha Long Bay World Natural Heritage

Bad (including crooked trees, trees without the top, pestilent, poor
growth and development) and Medium (the trees left).
The quality ratio of regenerated woody trees is determined by the
formula: Ni (%) = n/N x100
In which, Ni (%): Percentage of the trees i (with good, medium or
bad quality), ni is the total number of trees i (with good, medium or bad
quality), N is the total number of regenerated trees.
- Carrying out to classify regenerated trees according to their
height: Because the trees on the limestone mountains grow slowly, we


9
studied the height of regenerated trees with 4 levels (Level I: 150 cm).
- Study the distribution of regenerated trees on the soil surface
by determining the distance from a randomly selected regenerated tree
to the 6 nearest trees. Use standard U of Clark and Evans.
- Method identifying the origin of regenerated plants:
Regenerated trees from buds: those are regenerated plants from the
stem or roots of mother trees. Regenerated trees from seeds: those grew
from seeds of mother plants. The origin of regenerated plants is
determined according to the formula:
N%

x100

In which, N% is the percentage of trees regenerated from seeds
or buds; Ni is the number of trees regenerated from seeds or buds; N is
the total number of regenerated trees.
Learn some factors impacting the natural regeneration capacity

mountain (from the edge of the water to a height of 10m), with the
participation of mangrove plants such as Hibiscus tiliaceus, Thespesia
populnea; (ii) Shrub vegetation on limestone cliff slopes (from a height
of 10m up to 150-200m), without the participation of mangrove plants
and (iii) Vegetation in the limestone valleys.
The vegetation on the limestone mountains in Cam Pha city is
often affected by extreme weather conditions, with the impact of storms
so, in the vegetation, tall trees are few, most of them are the trees with
average height of 10-15 m, a diameter of 10-25 cm.
4.2. Characteristics of plant species composition on the limestone
mountains in Cam Pha city, Quang Ninh province
Flora of the limestone mountains in Cam Pha city is relatively
abundant, with 608 species, 370 genera, 118 families, belonging to
vascular plants. In particular, Magnoliophyta comprises the most of
families, genera and species (109 families, 354 genera and 577
species). Following by Polypodiophyta, which comprises 4 families, 11
genera and 24 species, the other branches having the number of genera,
of families and of species are fewer.
4.3. Characteristics of life forms of the vegetation on the limestone
mountains in Cam Pha city
Using Raunkiaer's life style division scale (1934), life form in the
limestone mountain vegetation in Cam Pha city as follows: SB = 28Me
+ 10Mi + 8Na + 8Ep + 12Lp + 12Hm + 11Ch + 7Cr + 4Th.
Statistical results show that Phanerophyte (Ph) group accounts for
the highest percentage, the lowest one is the Therophyte (Th). In the
Phanerophyte group, Lianas phanerophytes (Lp) account for the
highest percentage.


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formula of composition, in each plot the dominant tree species range
from 4 to 9 species.


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Figure 4.4. The vegetation in limestone mountain foot in Cam Pha
city (2016)

Note: Blnh- Boi loi nhot;Sltr- Soi la tron;Sa- Sang;Mt- May teo; TrbđTra bo đe; Trlch- Tra lam chieu;R- Rang; Vc- Vong cach; St- Son ta;SiqnhSi qua nho; Gi- Gia; Đm- Đon mong; Thmđ- Thien mon đong; Thh- Thanh
Huong; Đo- Đom; Phđ- Phen đen.

- Vegetation on cliff slopes:
The combined results from the survey lines on Cay May island,
Cu Cai island and Cai Bua island,... show that of total 18 investigated
routes, 31 species participate in the formula of composition, in each
investigated routes dominant tree species range from 3 to 6 species.

Figure 4.5. The vegetation on the limestone cliff slopes in Cam Pha
city (2016)
Note: Gnb- Gang nam bo;Sa- Sang; Siqnh- Si qua nho; So- Sop;Thh- Thanh Huong;
Sltr- Soi la tron; Trq- Trom quy; Sung gan đung; Ma- Mang; Vđmc- Vong đo mun coc;
Shl- Sung ha long; Ngbhl- Ngu gia bi ha long;Qg- Quyt gai; Bm- Bong moc.

4.5.2. Characteristics of density structure
The results show that the vegetation at the down of mountain has
the highest density (8,410 trees/ha), 1.6 times higher than the
vegetation in the valley and 20 times higher than the vegetation on the
cliff slope. The vegetation on the slopes and cliffs has the lowest
density of trees (413 trees/ha).

Johnson-schumacher
Verhulst
Parameter a
3-18
3-18
3-18
Parameter b0
13.521
19.368
12.805
Parameter b1
0.577
35.322
0.683
Parameter b2
0.041
37.572
0.056
R2
0.99507
0.995261
0.994921
AIC
-44.84719
-45.47957
-44.36834

The results show that the correlation coefficient R2 of the functions
is equivalent (0.995), so Gompertz, Johnson-schumacher and Verhulst
functions describe well the growth rate of the trunk diameter in the

3-18
17.043
37.017
33.084
0.995246
-45.42845

Verhulst
3-18
10.483
0.865
0.065
0.99479
-43.97494

The results show that all three growth functions are well simulated
for the height growth according to age. Based on that, three growth
functions including Gompertz, Schmacher and Verhulst were used to
simulate the growth for the variables of diameter and height of woody
trees in the limestone mountain vegetation in Cam Pha city.
The results show that all three functions can simulate well the
growth of forest trees in the study area. Correlation coefficients for
both diameter variable and height variable are very high (0.995).
However, if considering more accurately, the Schumacher function has
the highest compatibility, because the AIC value is the lowest in the
three models, which is true for both diameter and height variables. All
parameters of the regression model exist in the whole, since the Pr
values are much less than 0.05. This shows that the models are really
meaningful and can be applied to other areas with the same
characteristics of plants and other natural conditions.

(%)
In the valley
2938 2304 78.45 634 21.6
49
30
21
At the foot of
3880 2898 74.7 982 25.3
58
26
16
mountain
On the cliff
820
612 74.65 208 25.3
30
45
25
slopes
Average
2546 1938 76.24 608 23.8 45.7
33.7
20.7

The table shows that regenerated seedlings vary from 74% to 78%, on
average of 76%.
4.7.3. Distribution of regenerated woody trees according to the height
Distribution of regenerated timber tree according to the height is
presented in Table 4.21.
Table 4.21. Distribution of regenerated timber trees according to

1018
821
496
210
The results showed that the density of regenerated trees was the
highest at the height of 150 cm, regeneration density varies from 145
to 798 trees/ha, on average of 496 trees/ha.
4.7.4. Distribution of regenerated timber trees in horizontal plane
Results of distribution of regenerated woody trees are summarized
in the following table:
Table 4.22. Distribution of regenerated woody trees in


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horizontal plane
No.
Location
1 Vegetation in the valley
Vegetation at the down
2
of mountain
Vegetation on the cliff
3
slopes


trees in vegetation at the foot of the mountain and cliff slopes is
distributed in clusters. This distribution is consistent with the terrain of
limestone mountain. The vegetation in the valley has relatively flat
terrain and thick layer of soil, so when the fruits and seeds fall down,
they are distributed randomly on the ground. For vegetation at the
down of mountains and cliff slopes, due to steep terrain, when fruits
and seeds fall down, they tend to slip to the same position leading to
the regenerated trees distributed in clusters.
4.7.5. Factors affect the regeneration capacity of seedlings
4.7.5.1. Effect of terrain factors
The results on the influence of limestone mountain topography on
the quality and density of regenerated trees are shown in the following
Table 4.24:
Table 4.24. Effect of topographic factors on the regeneration capacity of
trees in the vegetation on the limestone mountains in Cam Pha City
Height

Terrain

No. of
tree/ha

Valley
1211
Foot of mountain
1475
Cliff slopes
368
Valley
987

41.69
225
17.80
746
50.60
510
34.67
219
14.73
123
33.53 187
51.18
58
15.29
551
55.92 246
25.04
190
19.05
753
77
245

59.64
36.51
45.25

290
91
194

45.66
35.41

196
20
23
43

23.90
12.69
11.39
11.80


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Cliff slopes

94

44

46.94

37

40.00

13

13.06

- In 1962, Ha Long Bay was ranked by the Ministry of Culture and
Information as scenic national monument. In 1994, Ha Long Bay was
recognized as a World Natural Heritage Site by UNESCO, because of
its exceptional value and global in landscape. In 2000, once again, Ha
Long Bay was recognized as a world natural heritage by UNESCO
with special value on geomorphological geology. In particular, Cam
Pha limestone mountain area is the buffer zone of Ha Long Bay.


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Therefore, the vegetation on the limestone mountains in Cam Pha city
plays a big role in creating this landscape value.
- Endemic species: Flora on the limestone mountains in Cam Pha
city has 16 endemic species of plants of Vietnam. Of them, there are 12
narrow endemic species (those only appear on Cat Ba, Ha Long and
Cam Pha islands) and 4 species are endemic species of Northeastern
Vietnam.
- Rare and precious species: On the rocky mountains in Cam Pha,
27 rare and precious plant species are recorded. 22 species of plants
was listed in the Vietnam Red Data Book (2007), in which there was 1
species at Critically Endangered (CR), 7 species at Endangered (EN),
14 species at Vulnerable (VU). 7 species are listed in the Appendix of
Decree No. 32/2006-NDCP. 6 species belongs to Appendix IIA
(limited to exploitation for commercial purposes). At the international
level, there is one species ranked Near Threatened (NT).
4.8.1.2. Economic value
The survey results determined the use value of the plant species
including the following groups:
- Group of trees for fuelwood:
There are 11 species of timber value, accounting for 1%, they are

limestone erosion, plant wastes in the vegetation create humus soil
layer on limestone mountains.
Humus layer plays an important role in moisturizing and is a living
environment for other organisms. Limestone mountain vegetation is also involved
in climate regulation, environmental cleanup.
- The vegetation on the limestone mountains is like a shield,
reducing the impact of storms.
4.8.1.4. Landscape value
- The vegetation on the limestone mountains with an average
height of 1-2 m, stems have many specific shapes of plants on rocky
mountains. Therefore, the vegetation on the rocky mountain has
contributed to adorn the landscape of limestone mountains.
- The vegetation also has the effect of keeping water in caves,
creating an interesting image effect of limestone cave landscape.
4.8.2. Situation of management and conservation of vegetation on the
limestone mountains
4.8.2.1. Agencies involved in managing the vegetation on the limestone
mountains in Cam Pha city
- In terms of state management: Each commune has a official
assisting the chairman of the commune People's Committee to manage
forestry development in the commune.
- In terms of expertise: Bai Tu Long Bay Management Board is a
professional agency to help Cam Pha City People's Committee manage,
preserve and promote the value of vegetation on the limestone
mountains. Bai Tu Long Bay Management Board has 46 staffs.
4.8.2.2. Documents, policies to direct the implementation of
conservation
Decision 1798/QD-UBND approving the Environmental Planning
of Halong Bay to 2020, vision to 2030 as a basis for managing the
ecological environment of Ha Long Bay (including the buffer zone);

Table 4.30. Summary of interview results on the impacts of people
on the limestone mountain vegetation
Impacts
Timber exploitation
Firewood exploitation
Ornamental plant exploitation
Medicinal plant exploitation
Exploitation of non-timber forest
products
Other impacts

Individual
No.
Per. (%)
1
3
5
16
7
23
10
33

No.
0
2
2
4

Official

Cam Pha at a low level.
- The results of SWOT analysis show the advantage in the
management of conservation is the vegetation on the limestone
mountains in Cam Pha city belonging to the buffer zone of Ha Long
bay (twice recognized by the UNESCO for geomorphological
landscape value).
Because of this importance, the limestone mountain vegetation in
Cam Pha city has a specialized agency to manage, called the Bai Tu
Long Bay Management Board.
Currently, the number of staffs in Bai Tu Long Bay Management
Board is 60. However, the quality of staff is still limited, failing to meet
the task requirements in conservation. So, the work of conservation of
vegetation on the limestone mountains has many opportunities and
challenges.
4.8.3. The risks of degradation of limestone mountain vegetation in
Cam Pha city, Quang Ninh province
Applying the evaluation method of Ngo Dinh Que (2011), we
conducted survey of 50 plots (area of 2500m2/plot) in the vegetations in
valley, at the down of mountain and 18 survey lines (5m wide and 50m
long) in the vegetationat on the cliff slopes.
Results show that the down of mountain and valley vegetations
has similar degradation level, over 70% of plots studied have low
degradation level, 16-20% of plots have degradation level at average,
8% of plots have serious degradation level, and no PLOT at very
serious degradation level. The vegetation on the cliff slopes has 67% at
average level of degeneration, the remaining 33% of studied routes has
serious degradation level. All three vegetations do not have any plot or
studied routes at very serious level of degradation.
The vegetation in the valley and the down of the mountain are at a
low degradation level, the vegetation on the cliff slopes is at moderate

(twice recognized by the UNESCO for geomorphological landscape
value). With such importance, the limestone mountain vegetation in
Cam Pha city is managed by a specialized agency, called the Bai Tu
Long Bay Management Board. Currently, the number of staffs in Bai
Tu Long Bay Management Board is 60. However, the quality of staffs
is still limited, failing to meet the task requirements in conservation.
Therefore, this difficulty leads to both opportunities and challenges for
the conservation of vegetation on limestone mountains.
Results of KIP and SWOT analysis show that the following groups
of measures need to be performed to conserve and sustainably use
limestone mountain vegetation in Cam Pha city, Quang Ninh:
4.9.1. Group of measures to raise awareness about biodiversity
conservation management