Characteristics of fuels and fire risk among the main forest types in Hoang Lien National Park
Management of Forest Resources and Environment
CHARACTERISTICS OF FUELS AND FIRE RISK AMONG THE MAIN
FOREST TYPES IN HOANG LIEN NATIONAL PARK
Tran Minh Canh1, Le Thai Son2, Le Xuan Thang3
1Hai Duong University
2Vietnam National University of Forestry
3Hoang Lien National Park
SUMMARY
Hoang Lien National Park has 25,113.66 ha of forest under its management, including the main forest types as
natural broadleaf evergreen forest (poor; average and rehabilitation forests), bamboo, bamboo and mixed
forests, and plantation forest. There are small areas of natural rich forest left, mainly located in strictly protected
zone, and 2,143.75 ha of uncovered land or area of regenerating woody plants. There are clear differences in
terms of fuels among forest types that were clarified by using indicators as trunk height, height and cover of
understory vegetation, load and moisture of fuels. From the characteristics of fuels, the study divided fire risk
for forests, shrublands and grasslands into 4 levels of danger. As a result, shrubs and grasses and bamboo forest
are at highest fire risk (level IV); Plantation forest and evergreen poor forest are at high risk of fire (level III);
Rehabilitation forests are at medium risk (level II); and evergreen average and rich forests are at low risk (level
I). From the results above, this study also has created a map of fire risk division for forest types in Hoang Lien
National Park.
Keywords: Characteristics of fuels, forestfire prevention and suppression, forestfire risk, forest types,
Hoang Lien National Park.
district in Lao Cai province and Tan Uyen
district in Lai Chau province. Hoang Lien
National Park is one of the top biodiversity
centers in Vietnam. This is a home for many
endemic species listed in the Red Data Book of
Vietnam as well as the The International Union
for Conservation of Nature (IUCN) Red List.
However, in recent years, forest fires have
occurred in this park, thus affecting both the
area and quality of forests along with the local
socio-economic development.
I. INTRODUCTION
Forest fire is one of the most important
causes of deforestation and forest degradation,
affecting many aspects of socio-economic
development. Therefore, forest fire prevention
and suppression is always of interest in many
countries around the world, including Vietnam.
The presence of forest fires requires the
interaction of three elements: heat source,
oxygen and fuels (combustible materials). In
fact, fuels have great influence on both the
emergence and spread of forest fire and this
element is the most preferred object by humans
control the fire (Heikkila et al., 2007). To
assess the risk of fire among forests in different
statuses, as the basis for proposing solutions
for forest fire prevention and suppression to a
local or forest protection units, it is necessary
to study on the characteristics of fuels.
This paper presents the results of the study,
which has assessed the fuel characteristics and
identified the fire risks of the main forest types
to build up basis for proposing solutions for
forest fire prevention and suppression in
Hoang Lien National Park.
II. RESEARCH METHODOLOGY
2.1. Study subjects and site
The study subjects include characteristics of
fuels under the main forest types in Hoang Lien
National Park: medium evergreen natural forest
(TXB); poor evergreen natural forest (TXP);
Hoang Lien National Park, with a total area
of 28,509 ha, consists of 27 sub-zones
distributing in 7 communes and towns in Sa Pa
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poor evergreen natural forest (TXN); woody +
bamboo mixed forest (HG1, TNK); plantation
forest (RTG) and non-forest land (DT1, DT2)
in Ta Van, Ban Ho and San Sa Ho communes
(three communes with frequent forest fires) in Sa
Pa district, Hoang Lien National Park (Fig. 1).
Fig. 1. Maps of study sites in Sa Pa district, Lao Cai province
plant species and measuring their diameter at
breast height (DBH), crown diameter, tree top
height, trunk height and canopy cover were
conducted.
2.2. Methodology
2.2.1. Secondary data
The study has used secondary data and
information in relation to natural and socio-
economic conditions, forest fire situation and
forest fire prevention and suppression activities
in the study area (Fig. 1).
- Survey on regeneration trees and
unverstory vegetation: surveying on 9 quadrats
with area at least 4 m2 inside each PSP to
identify species, height, cover, growing status
(good, medium, poor) and type (seeding or
coppice) of regeneration trees was carried out.
- Survey on fuel characteristic: surveying on
five quadrats with area of 1 m2 inside each PSP
to collect information on composition, mass,
moisture, height of understorey vegetation,
thickness of litter layer, combustible ability to
build a basis for assessing risk of forest fires
among different forest types was conducted.
b) Forest classification by fire risk
2.2.2. Field survey
a) Survey on forest and fuel characteristics of
the main forest types
The study has executed forest classification
according to the Circular 34/2009/TT-
BNNPTNT by the Ministry of Agriculture and
Rural Development (Vietnam Government,
2006). After identifying the main forest types
in high elevation areas that forest fires often
occur, the study has established permanent
sample plots (PSPs). Within each forest type,
there were 2 ÷ 4 PSPs of 500 m2 established
depending on the area available. There was a
total of 45 PSPs set up this study.
Forest classification by fire risk was
carried out according to the multi-criteria
method. Criteria used for analyis and ranking
of forest fire risk included volume, fuel
- Survey on overstorey trees: identifying
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n
distribution, cover, trunk height and
understorey vegetation height. To classify
forests by fire risk, the study uses Ect - the
Effective Indicator of Farming system
(Nijikam, 1982). Ect can be calculated as
followings:
Ecti =
(Fij*Pj)
(1)
j1
Where: Ecti is the total effective indicator
of all the criteria from the PSP i; Pj is the
weight coefficient referring to the importance
of the criterion j; n is the number of criteria
used for Multi-Criteria Analysis (MCA).
(4)- Forest classification by Ect (or Fire
Risk Index)
The average of Ect indices from PSPs in the
same forest type is used for forest classification by
fire risk. Forest types with familiar Ect are
categorized into the same group that means
different groups contain forest types with different
risk of fire.
(1)- Characteristic table in association with
fire risk of forest types was created;
(2)- Computing Fij values for each
criterion: Fij refers to a distinct value for the
criterion “j” in the PSP “i”. There many ways
to calculate Fij values.
If an indicator benefits with increasing, it
is standardized as Fij = xij/xmax , in which xij
is the value of the criterion j from the PSP i,
Xmax is the maximum value existing as in the
criterion j. In contrast, if an indicator
benefits with decreasing, the standardized
value is Fij = 1 - (xij/xmax). To enhance the
accuracy of the analysis, the study defines
the weight coefficient Pj for the criterion j by
expert consultation.
III. RESULT AND DISCUSSION
3.1. Status of forest resources and forest fire
situation in Hoang Lien National Park
3.1.1. Status of Forest and Forest land
According to the forest inventory result of
Hoang Lien National Park in 2016 (Hoang
Lien National Park Forest Protection Service,
2016), area by forest types and non-forest land
are shown in table 1.
(3)- Ect calculation
Table 1. Status of forest and forest land in Hoang Lien National Park
Proportion
to forest area (%)
Area
(ha)
Proportion to total
natural area (%)
Land use
Total natural area
Forest area
Natural forest
28,509.00
25,113.66
24,857.00
24,243.19
826,87
100
100
98.98
96.53
1
1.1
88.09
87.19
85.04
1.1.1 Woody evergreen forest
- Rich forest
- Medium forest
5,835.19
14,127.82
3,453.31
215.57
- Poor forest
- Rehabilitation forest
1.1.2 Wood + bamboo mixed forest
1.1.3 Bamboo forest
0.86
1.59
1.19
0.76
1.40
0.90
7.52
4.39
398.28
1.2
2
3
Plantation forest
Non-forest land
Others
256.66
2,143.75
1,251.58
Source: Hoang Lien National Park Forest Protection Service (2016)
The statistics show that the natural forest
area of Hoang Lien National Park is quite large
of 24,857.0 ha (accounting for 87.19% of the
natural area and 98.98% of the total forest
area). There are 24,243.19 ha of forest
(equivalent to 97.53% of natural forest area),
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mixed wood and bamboo forest (0.87%),
bamboo forest (1.6%); plantation forest
accounts for only 0.9% of the natural area and
land without forest is 7.52%. Forest area
includes rich forest (826.87 ha), medium forest
(5,835.19 ha), poor forest (14,127.82 ha),
rehabilitation forest (3,453.31 ha). It is
remarkable that there is non-forest land
(DT1; DT2) of 2,143.75 ha, accounting for
7.52% of the total natural area in Hoang Lien
National Park.
leaved evergreen rehabilitation reforest
(rehabilitation forest), bare land or
regenerating woody tree (non-forest land),
bamboo forest and woody plantation forest
(plantation). There is very small area of natural
rich forests (3.29% of total forest area) along
with medium timber forests, which are usually
distributed in strictly protected areas. These
forest types have high levels of biodiversity
and are areas of interest for protection.
3.1.2. Forest fire situation in Hoang Lien
National Park
The above results show that the forest types
with large area of Hoang Lien National Park
include evergreen broad-leaved poor forest
(poor forest), medium evergreen broad-leaved
medium forest (medium forest), natural broad-
According to the statistics by Hoang Lien
National Park Forest Protection Service, forest
fires in Hoang Lien National Park in the last 8
years are described as in table 2.
Table 2. Forest fire area in Hoang Lien National Park (2009 - 2016)
Forest type area (ha)
TXN RTG DT1 & DT2
80.55
Area
(ha)
Time
Commune
Village
Sub-zone
TXP
3.40
36.00
299.00 283.00 16.00
2/2009
Ta Van
Seo My Ty
286
287
83.95
36.00
Ma Quai Ho
291
295b
296
Ban Ho
51.00
75.00
51.00
Ta Trung Ho
69.00 6.00
2/2010
302
286
272
59.00
54.00 5.00
Ta Van
Seo My Ty
Sin Chai
154.00 145.00 9.00
San Sa Ho
44.00
42.20 1.80
295a
292a
283b
296
13.85
59.75
3.42
21.00
12.70
8.5 5.35
45.25 14.5
3/2012
3/2013
3/2014
Ta Van
Seo My Ty
Ban Ho
Ban Ho
Ta Van
Seo Trung Ho
Ta Trung Ho
Seo My Ty
3.42
19.40
7.50
1.6
5.2
292a
2/2015
2/2016
Ban Ho
Ta Van
Total
Ta Trung Ho
Seo My Ty,
Ta Van Giay
12.70
0.54
0.98
12.16
9.80
208
12.48
1.70
937.85 742.27 57.65 1.70
132.63
Source: Hoang Lien National Park Forest Protection Service (2017)
As in the statistics, in the period 2009 -
2016, fires damaged 937.85 ha of forest within
Hoang Lien National Park. Forest fires
occurred mainly in rehabilitation forest
(79.51%), followed by grassland and shrubland
(14.16%), poor forest (6.15%) and plantation
forest (0.18%). Particularly, the largest area of
forest fire occurred in 2010 with 718 ha
(76.56% of total forest fire area in the 8 - year
period). Forest fires usually occurred in
February and March. During this period, the
weather was favorable for the emergence and
spread of forest fires. It also coincided with the
time indigenous people prepare for cultivation.
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Areas with the most frecquencies of forest fire
difficult to be managed.
occurrence are Ta Trung Ho, Seo Trung Ho,
Ma Quai Ho (Ban Ho Commune), Seo My Ty
(Ta Van Commune), Sin Chai (San Sa Ho
Commune). The main drivers of forest fires
here are using slash-and-burn fire, farmland
preparation, cardamom cultivation and natural
honey harvesting. These activities are very
3.2. Forest and combustible material
characteristics in the main forest types
3.2.1. Overstorey trees
The characteristics of some overstorey
species among the main forest types in the
communes Ta Van, Ban Ho and San Sa Ho are
summarized in table 3.
Table 3. Overstorey tree survey’s results
Tree Top Trunk Canopy
density height height
Forest
type
DBH
(cm)
Canopy
cover (%)
Commune
diameter
(m)
(tree/ha)
(m)
10.05
10.20
14.80
8.20
(m)
3.48
4.36
11.23
3.20
3.17
5.33
9.94
3.25
6.85
TXN
TXP
TXB
RTG
TXN
TXP
TXB
RTG
TXP
295
411
688
820
220
355
2.86
10.64
13.38
25.48
10.50
7.00
13.60
28.73
10.69
15.36
33
46
57
60
31
51
62
63
52
3.08
4.27
2.70
3.00
2.95
5.63
2.90
2.59
San Sa Ho
9.50
11.64
16.99
8.80
Ta Van
Ban Ho
667
780
560
11.80
Table 3 shows that the density and the
average growth of overstorey trees are at
relatively low levels and different between
forest types. The natural forest here has been
affected significantly; the canopy layer
structure is broken; forest cover is only at
medium (from 46 to 62%) or even low levels
such as Poor forest - TXN (San Tu Ho
commune: 0.33, Ta Van commune: 0.31).
Between forest types, the DBH is in large
variation. When comparing forests in San Sa
Ho and Ta Van communes, the density and
growth of the same forest type are relatively
homogeneous.
demanding species, is with unstably medium
growth rate. Trees of this forest type grow
slowly; the average height is quite low; the
density is only from 355 to 411 trees ha-1,
except in the Ban Ho commune, the density is
quite high at 560 trees ha-1. Plantation forest,
planted with mainly Cunninghamia lanceolata
(Lamb.) Hook., Schima wallichii (DC.) Korth
and Alnus nepalensis D. Don, has well grown.
This forest type, with high density and cover,
needs high-quality treatment, management and
protection to avoid any negative influence.
In Ta Van commune, some dominant trees
such as S. wallichii (DC.) Korth, Camellia sp,
Lithocarpus hemisphaericus, Rhododendron
densifolium K. M. Feng... are able to fast grow
and develop well. However, most of them are
not economically valuable. In San Sa Ho
commune, plants such as S. wallichii (DC.)
Korth, Cinnamomum tonkinensis Pitard, A.
nepalensis D. Don, R. densifolium K. M. Feng
Medium forest - TXB has the best growth
rate, most of which are trees > 25 cm in
diameter and have grown well. Due to the
regeneration time in this forest type longer
than the rest, an ecologically dominant tree
layer has been formed. Rehabilitation forest -
TXP, including typically fast-growing light-
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and Magnolia nana Dandy are dominant. In
Ban Ho commune, forest is mainly
rehabilitation; the number of species is much
lower than that of Ta Van and San Sa Ho
communes. There are only four dominant
species here: Claoxylon cascarrioides,
Camellia sp., S. wallichii (DC.) Korth and C.
tonkinensis Pitard.
regeneration from these forest types.
3.2.3. Characteristics of combustible materials
from forest types within the study area
a) Composition and height of the understorey
layer
Composition and height of the understorey
layer, which are the results of the survey in this
study, are summarized in table 4.
From the results in table 4, characteristics of
understorey layer in the study area can be
concluded as folowings:
3.2.2. Regeneration trees
The survey on the characteristics of
regeneration trees shows that some species,
such as S. wallichi (DC.) Korth, R. densifolium
K. M. Feng, C. tonkinensis Pitard, several of
the genus Michelia, A. nepalensis D. Don,
The understorey cover in grasslands and
shrublands in Ban Ho commune is of medium
height and low coverage. In contrast, the
coverage of this layer in San Sa Ho and Ta Van
communes is quite high (71 - 73%) with the
composition including flammable plants such as
S. petelotii (A. Camusa) A. Camus, X.
sikkimensis (Hieron.) Copel., D. linearis
(Burm.f.) Underw, S. palmifolia (Koen) Stapf,
etc. This is a high-risk source of combustible
materials. Especially in the dry season, they will
die and be naturally dried that become a
massive source of fuels. Hence, if forest fire
occurs, it will spread rapidly on a large scale. In
rehabilitation forest and poor forest, in general,
the understorey layer is at medium level, with
the height of 41 - 64 cm and the coverage of
roughly 50%.
Exbuclandia tonkinensis (Lecomte) V. Steen.,
Lantana camara and Vernicia montana Lour.
are present in both understorey and overstorey
forest layers in the study area. This has partly
demonstrated that they are adaptable to site
conditions. In addition, some species,
including Michelia fuscata, Quercus sp. and
Alangium chinense, participate in building rich
and diverse forest structures in terms of species
composition. These are native species with
good regeneration ability. They, especially A.
nepalensis D. Don and S. wallichii (DC.)
Korth, can appear as individuals or big clusters
along paths or deeply within forests.
Regenerating tree composition is not much
different with which from overstorey trees.
Indeed, natural seedlings of many species, such
as S. wallichii (DC.) Korth, A. nepalensis D.
Don, Eurya ciliate, Camellia sp. and several of
the genus Castanea, are growing under seed
bearers which contribute to overstorey
composition. However, there is still a need to
have more management measures from the
Forest Protection Services, local government
and people to achieve a more effective
In medium forests, the understorey layer is
of medium height (92 cm in San Sa Ho
commune and 85 cm in Ta Van commune)
with the corresponding coverage of 75% and
85% respectively. This is a relatively high
level of forest cover, in which some species are
hygric and contain high water content.
Plantation forests are at medium level of height
and cover. However, this forest type is often
treated and cleaned by people that make the
understorey composition quite simple.
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Table 4. Results from survey of understorey layer
Average
height
(cm)
Crop
type
Cover
(%)
Commune
Main species
Sinarundinaria petelotii (A. Camusa) A. Camus,
Grassland, Melastoma imbricata Wall. ex C.B. Clarke, Setaria
55
41
73
49
shrubland palmifolia (Koen) Stapf,
Xiphopteris sikkimensis
(Hieron.) Copel.
M. imbricata Wall. ex C.B. Clarke, X. sikkimensis
(Hieron.) Copel., S. palmifolia (Koen) Stapf,
Dicranopteris linearis (Burm.f.) Underw., Bidens pilasa
L., Rubus Alceaefolius Poir., Physalis angulata.
Poor forest
San Sa Ho
X. sikkimensis (Hieron.) Copel., D. linearis (Burm.f.)
Underw., S. palmifolia (Koen) Stapf, Pogonatherium
crinitum (Thunb.) Kunth, Herminium lanceum (Thunb. ex
Sw.) Vuijk., R. Alceaefolius Poir., S. petelotii (A. Camusa)
A. Camus, P, angulata, Chromalaena odorata (L.).
S. palmifolia (Koen) Stapf, X. sikkimensis (Hieron.) Copel.,
Dysoxylum tonkinense Chev. ex Pellegr., R. Alceaefolius
Poir. (R. moluccanus L), Tradescantia pallida, Psychotria
rubra (Lour.) Poir (P. reevesii Wall), M. imbricata Wall. ex
C.B. Clarke, Phrynium placentarium...
Rehabilitati
on forest
45
92
45
75
Medium
forest
X. sikkimensis (Hieron.) Copel., Dicranopteris linearis
(Burm.f.) Underw., Setaria palmifolia (Koen) Stapf, R.
Alceaefolius Poir., C. odorata (L.).
Plantation
forest
67
49
60
71
S. petelotii (A. Camusa) A. Camus, P. angulata, S.
Grassland, palmifolia (Koen) Stapf, M. imbricata Wall. ex C.B.
shrubland Clarke, D. linearis (Burm.f.) Underw., X. sikkimensis
(Hieron.) Copel…
D. linearis (Burm.f.) Underw., C. odorata (L.), M.
imbricata Wall. ex C.B. Clarke, Piper chaudocanum C.
DC, R. Alceaefolius Poir., S. palmifolia (Koen) Stapf, X.
sikkimensis (Hieron.) Copel., P. angulata...
S. palmifolia (Koen) Stapf, Setaria glauca (L.) P.
Poor forest
64
41
41
53
Beauv., X. sikkimensis (Hieron.) Copel., M. imbricata
Rehabilitati
Wall. ex C.B. Clarke, D. linearis (Burm.f.) Underw.,
on forest
Ta Van
P. angulata, Amomum aromaticum Roxb., R.
Alceaefolius Poir. (R.moluccanus L)...
X. sikkimensis (Hieron.) Copel., S. palmifolia (Koen) Stapf,
Medium
M. imbricata Wall. ex C.B. Clarke, D. linearis (Burm.f.)
forest
85
85
69
55
80
53
Underw., Psychotria rubra(Lour.), A. aromaticum Roxb.
S. petelotii (A. Camusa) A. Camus, Bamboo, S.
palmifolia (Koen) Stapf, Amomum lacteum Ridl., D.
linearis (Burm.f.) Underw., Phrynium placentarium…
Setaria palmifolia (Koen) Stapf, X. sikkimensis
(Hieron.) Copel., R. Alceaefolius Poir. (R. moluccanus
L), A. aromaticum Roxb.
Bamboo
forest
Plantation
forest
Calamus sp., Maesa SP., X. sikkimensis (Hieron.)
Rehabilitati Copel., S. palmifolia (Koen) Stapf, M. imbricata Wall.
32
25
45
on forest
ex C.B. Clarke, Clerodendron infortunatum L,
Dysoxylum tonkinense Chev. ex Pellegr....
Ban Ho
Sinobambusa sat (Bal.) T.Q. Nguyen Lau, Setaria
Grassland, palmifolia (Koen) Stapf, X. sikkimensis (Hieron.)
shrubland Copel., Achyranthes aspera L., Bidens pilasa L., S.
petelotii (A. Camusa) A. Camus…
30
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of its direct effects on the flammable ability,
b) Mass and water content of fuels from
forest types
emergence and spread speed of forest fires as
well as the level of damage caused by the fires.
These characteristics are in table 5.
Mass and water content (relative moisture
content) of fuels is a significant factor because
Table 5. Mass and water content of fuels from forest types
Mass (tons/ha )
Green
material
11.31
10.93
8.49
Water content
(%)
Commune
Forest type
Dried
material
11.21
8.74
Total
Grassland, shrubland
Poor forest
22.52
19.67
19.53
17.01
19.67
24.59
20.41
19.39
28.13
15.22
20.54
18.84
22.99
13.33
23.10
21.31
30.41
22.23
14.47
21.37
25.66
32.63
16.73
24.09
20.65
15.43
San Sa Ho
Rehabilitation forest
Medium forest
11.04
13.99
13.24
11.49
7.11
3.02
Plantation forest
Grassland, shrubland
Poor forest
6.43
13.10
13.30
12.04
21.61
8.72
Rehabilitation forest
Medium forest
7.35
Ta Van
Ban Ho
6.52
Bamboo forest
6.50
Plantation forest
Rehabilitation forest
Grassland, shrubland
13.56
7.52
6.98
11.32
12.24
10.75
The results show that water content is quite
high in medium forests (30.41% in San Sa Ho
commune and 32.63% in Ta Van commune).
This may be caused by high canopy cover. The
canopy layer is capable of partly blocking solar
radiations along with the ability of water
retaining that make combustible materials on
the ground always of certain moisture. In
rehabilitation and poor forests, the content of
water in fuels is average from 20.65% -
25.66%.
Combustible materials in grasslands and
shrublands have average water content at the
lowest level in the study area (13.33% in San
Sa Ho commune, 14.47% in Ta Van commune
and 15.43% in Ban Ho commune). All they are
at high level of fire risk. The understorey
composition includes flammable plants, such
as D. linearis (Burm.f.) Underw., C. odorata
(L.) King et Robinson and X. sikkimensis
(Hieron.) Copel., etc., that push the probability
of fire outbreak and spread to a high level if
fire occurs. Most of the plantation forests is
located in a lower-elevation area or people
have planted Amomum aromaticum Roxb.
under the canopy that decrease fire risk to the
medium level. Indeed, A. aromaticum Roxb. is
a broad-crown plant that can cover the soil and
save water to hold fuel moisture at a moderate
level.
Table 5 shows that there is a massive
amount of combustible materials among forest
area. Grasslands, shrublands and medium
forests have the largest mass of fuels (> 20
tons/ha) that is very dangerous to forest fire.
In other forest types, the amount of fuels is
medium.
However,
well-developed
understorey layers along with the severe
weather condition in the North West (i.e. long
periods of dry and hot weather) make the fire
risk here need to be considered.
3.2.4. Assessment on fire risk of forests and
forest lands in Hoang Lien National Park
From the analysis in the previous sections, the
study classified fire risk of studied forest types by
standardizing the criteria by the opposite method
92
JOURNAL OF FORESTRY SCIENCE AND TECHNOLOGY NO. 2 - 2018
Management of Forest Resources and Environment
(Nguyen Hai Tuat, 2010), in which: Criterion 1 is
these criteria are defined by expert consultation:
coefficient of 0.25 for Criterion 1 and Criterion 2;
0.2 for Criterion 3; and 0.15 for Criterion 4 and
Criterion 5. The statistics of the criteria are in
table 6.
fuel water content - Wv (%); Criterion 2: fuel
mass - Mv (ton/ha); Criterion 3: height of
understorey trees - Hcb (cm); Criterion 4: trunk
height - Hdc (m); Criterion 5: understorey
coverage - CP (%). The weight coefficients of
Table 6. Criteria for assessment on fire risk of forests and forest lands
Forest type
Grassland, shrubland
Poor forest
Wv (%)
14.41
22.23
23.49
31.52
16.73
14.41
Mv (ton/ha)
23.37
Hcb (cm)
52.0
CP (%)
72.0
Hdc (m)
0.0
20.41
52.5
45.0
4.5
Rehabilitation forest
Medium forest
19.46
46.2
47.7
4.7
18.10
65.0
80.0
10.6
0.0
Bamboo forest
15.22
85.0
80.0
Plantation forest
20.11
68.0
56.5
3.2
The criteria above were standardized by the
opposite method to calculate the Ect index. The
quantification results are in table 7.
Table 7. Results of criterion standardization
Forest type
Grassland, shrubland
Poor forest
Wv (%)
0.136
0.074
0.064
0.000
0.117
0.136
Mv (ton/ha)
0.250
Hcb (cm)
0.122
CP (%) Hdc (m)
Ect
0.135
0.084
0.089
0.150
0.150
0.106
0.150
0.086
0.083
0.000
0.150
0.105
0.793
0.689
0.553
0.497
0.780
0.721
0.218
0.124
Rehabilitation forest
Medium forest
0.208
0.109
0.194
0.153
Bamboo forest
0.163
0.200
Plantation forest
0.215
0.160
Based on the range of changes in the
overall indicator Ect, the study has classified
the fire risk into 4 level as below:
at low risk (level I). Rich forests with a small
area are classified as level I due to their
conditions unsuitable for forest fire.
+ Level I - Low risk of fire (Ect < 0.55);
+ Level II - Medium risk of fire (0.55 ≤ Ect
< 0.65);
+ Level III - High risk of fire (0.65 ≤ Ect <
0.75);
The results of the classification may also be
relative because forest fires are actually
influenced by many other factors such as site
condition, impact of people, and especially
weather. Rehabilitation forests now are only at
medium level because of high moisture, but
during hot and windy periods, heavy winds can
push the fire risk to the highest level. In reality,
the burnt areas of regeneration forest is the
largest compared to other forest types because
in the subsequent years from fire, these areas
have been partly counted as regeneration
forest.
+ Level IV - Extremely high risk of fire (Ect
≥ 0.75).
According to the classification: shrublands
and grasslands (category Ic) and bamboo forest
are at highest fire risk (level IV); Plantation
forest and evergreen poor forest are at high risk
of fire (level III); Forest without volume is at
medium risk (level II); and evergreen average are
JOURNAL OF FORESTRY SCIENCE AND TECHNOLOGY NO. 2 - 2018
93
Management of Forest Resources and Environment
have built the fire risk map for the study
area. Each level is represented by a single
color as in fig. 2.
3.2.5. Building fire risk map of forest types in
Hoang Lien National Park
From the fire risk classification, the study
FIRE RISK MAP
Hoang Lien National Park
Fig. 2. Fire risk map of forest types in the study area
According to Fig. 2, there is not large area
IV. CONCLUSION
of forest with low fire risk, especially a very
small area of medium and rich forests. These
forest types are scattered over 4 communes but
often located in area within strictly protected
sub-zones, with rugged terrain or at high
elevation. Plantation forests at high fire risk are
often located near the national highway from
Sa Pa to Lai Chau province.
The high and very high fire risk forests are
scattered throughout all communes in Hoang
Lien National Park. However, the risk is
concentrated in the villages Seo My Ty, Den
Thang and Seo Trung Ho - Ta Van commune;
the villages Ta Trung Ho and Ma Quai Ho -
Ban Ho commune; and area on Nui Xe
mountain (adjacent to Lai Chau) - San Sa Ho
commune. These high risk forest types
concentrate to the North East of the
communes. This is where fires occur annually
that prove the high level of fire risk in these
locations. In addition, there are ethnic
minorities living in these areas that is difficult
to control sources of fire.
- Hoang Lien National Park currently has
25,113.66 ha of forest, with the main types as
poor and medium evergreen broad-leaved
lowland forest, bamboo forest and plantation
forest. There are very small area of natural
rich forest often located in strictly protected
sub-zones. The rest of national park area is
2,143.75 ha of bare land with or without
regeneration trees.
- From 2009 to 2016, fires damaged 937.85
ha of forest in Hoang Lien National Park.
Forest fire has occured mainly in rehabilitation
forest (79.51%), followed by grasslands and
shrublands (14.16%), poor forest (6.15%) and
plantation forest (0.18%). The fire season is
during February and March, mainly due to
slash-and-burn agriculture, hunting and honey-
making. Frequent-fire area are concentrated in
Ban Ho, Ta Van and San Sa Ho communes.
- Poor and rehabilitation forests have been
greatly influenced; the canopy structure is broken
down, the forest cover is at low level (31 - 52%)
facilitating the understorey vegetation layer to
94
JOURNAL OF FORESTRY SCIENCE AND TECHNOLOGY NO. 2 - 2018
Management of Forest Resources and Environment
well develop. In each forest type, there are
different vegetation characteristics, thus forming
different fuel sources for fire.
forest fire characteristics and other socio-
economic factors, to propose solution for forest
fire prevention and suppression following
scientific and practical bases.
- There is a clear difference in fuel
characteristics among forest types, including
trunk height, height and coverage of
understorey trees, mass and moisture of
combustible materials.
- Based on characteristics of combustible
materials, the study successfully classified forest
types by fire risk into 4 levels as follows:
shrublands and grasslands (category Ic) and
bamboo forest are at highest fire risk (level IV);
Plantation forest and evergreen poor forest are at
high risk of fire (level III); Forest without
volume is at medium risk (level II) and evergreen
average are at low risk (level I).
REFERENCES
1. Heikkila T. V., Gronqvist R., Jurvelius R. M.
(2010). Wildland Fire Management. Forest Management
Team, Forestry Department, FAO. Rome.
2. Hoang Lien National Park (2014). Adjustment and
supplement to the plan for forest fire prevention and
suppression in the dry season 2014-2015.
3. Hoang Lien National Park (2016). Statistics of
forest area in Hoang Lien National Park.
4. Hoang Lien National Park (2017). Report on fire
situation in Hoang Lien National Park.
5. Nguyen Hai Tuat, Tran Quang Bao, Vu Tien
Thinh (2010). Quantitative ecological research methods.
Agriculture publisher, Ha Noi.
6. Vietnam Government (2006). The decree No.
09/2006/ND-CP on fire prevention and supppression.
Ha Noi.
From those results, it is necessary to further
study on other factors, such as terrain, climate,
ĐẶC ĐIỂM VẬT LIỆU VÀ NGUY CƠ CHÁY Ở CÁC TRẠNG THÁI RỪNG
CHỦ YẾU TẠI VƯỜN QUỐC GIA HOÀNG LIÊN
Trần Minh Cảnh1, Lê Thái Sơn2, Lê Xuân Thắng3
1Trường Đại học Hải Dương
2Trường Đại học Lâm nghiệp
3Vườn Quốc gia Hoàng Liên
TÓM TẮT
Vườn quốc gia Hoàng Liên hiện quản lý 25.113,66 ha rừng, với các trạng thái chủ yếu: rừng gỗ tự nhiên lá
rộng thường xanh nghèo, trung bình, rừng phục hồi, rừng tre nứa và rừng trồng. Rừng tự nhiên giàu hiện còn
rất ít, thường phân bố ở phân khu bảo vệ nghiêm ngặt và 2.143,75 ha đất trống không hoặc có cây gỗ tái sinh.
Có sự khác nhau khá rõ về đặc điểm vật liệu cháy (VLC) ở các trạng thái rừng, qua những chỉ tiêu gồm: Chiều
cao dưới cành tầng cây cao, chiều cao và độ che phủ của lớp thảm tươi cây bụi, khối lượng và độ ẩm VLC. Từ
đặc điểm VLC, phân nguy cơ cháy của các trạng thái rừng và trảng cỏ, cây bụi thành 4 cấp theo mức độ nguy
hiểm với lửa như sau: trạng thái trảng cỏ cây bụi và rừng tre nứa có nguy cơ cháy cao nhất (cấp IV); trạng thái
rừng trồng và rừng thường xanh nghèo có nguy cơ cháy ở mức cao (cấp III); rừng phục hồi có nguy cơ cháy ở
mức trung bình (cấp II); rừng thường xanh trung bình và giàu có nguy cơ cháy thấp (cấp I). Từ kết quả phân
cấp nguy cơ cháy rừng như trên, xây dựng bản đồ phân cấp nguy cơ cháy cho các trạng thái rừng ở Vườn Quốc
gia Hoàng Liên.
Từ khóa: Đặc điểm vật liệu cháy, nguy cơ cháy rừng, phòng cháy - chữa cháy rừng, trạng thái rừng,
Vườn Quốc gia Hoàng Liên.
Received
Revised
Accepted
: 07/02/2018
: 06/3/2018
: 14/3/2018
JOURNAL OF FORESTRY SCIENCE AND TECHNOLOGY NO. 2 - 2018
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