Journal of Global Resources

Volume 3

July 2016
Page 16-26
ISSN: 2395-3160 (Print), 2455-2445 (Online)

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FOREST FIRE RISK ZONE MAPPING IN CHINNAR WILDLIFE SANCTUARY, KERALA,
INDIA: A STUDY USING GEOSPATIAL TOOLSAjin R. S*1, Ana-Maria Loghin2, Vinod P. G1 and Mathew K. Jacob3
1Geomatics Division, GeoVin Solutions Pvt. Ltd., Thiruvananthapuram, Kerala, India
2

Faculty of Hydrotechnical Engineering, Geodesy and Environmental Engineering, Gheorghe
Asachi Technical University of Iasi, Romania
3

Post Graduate Department of Geology, Sree Narayana College, Sivagiri, Kerala, India*Email: ajinares@gmail.com

Abstract: A Forest fire is a major environmental disaster occurring in many countries of theworld, causing damage to ecology, economy, and property. This natural phenomenon causes
major changes in the forest structure and function, and above all this, it endangers wildlife.
Fires are one of the major natural risks in the forests of the Western Ghats, a biodiversity
hotspot in India. The present study area is also prone to fire, where a total of 13 forest fires
were recorded for the last 11 years. The objective of this study is to demarcate the forest firerisk zones in the Chinnar Wildlife Sanctuary using geospatial tools. In order to prepare the firerisk zone map, the Fire Risk Index method is used. In the mapping process, factors such as
land cover type, slope, distance from settlement, distance from road, and elevation areselected. According to their sensitivity to forest fires, five different categories of risk zones aredemarcated. Thus the final forest fire risk zone map of the study area comprises very low, low,moderate, high, and very high risk zones. The result of the study is validated with the fireincidence data, and shows that 76.92 percent of fire incidences are in the high and very highrisk zones. This study based on geospatial technology will help the authorities to easily identify
the risk zones, and can offer an effective control for a better planning and preparation of forest
fire control and management.
Key words: Forest Fire, Western Ghats, Geospatial Tools, Risk Zones
1. Introduction
Forests are one of the most important natural resources on earth, and they play a crucial rolein maintaining the balance of climate, conserving soil, water, and biodiversity (Kuter et al.,2011). Most of the forests are facing ever increasing risks, especially from fires. Forest fires
are influenced directly or indirectly by geomorphology, climate and anthropogenic activities.
Fires can be caused by natural as well as human induced factors. Most of the forest fires
occurring in India are due to anthropogenic activities. These forests are facing seriouspressure from people because of the increasing demand for forest products and forest land.
Uncontrolled fire can cause loss of forest resources, loss of biodiversity, land degradation,
adverse health problems, and even loss of life. The present study area, Chinnar Wildlife
Sanctuary, part of the Western Ghats, a biodiversity hotspot in India and UNESCO world
heritage site is also prone to forest fires, with a total of 13 forest fires reported for the last 11years. In the study area, forest fires occur more frequently during the period between themonths of December and May.
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Remote Sensing (RS) and Geographic Information System (GIS) techniques are
effective tools and utilized by many researchers (Ajin et al., 2015; Ajin et al., 2014; Gerdzheva,2014; Soto, 2012; Ponomarev, 2011; Puri et al., 2011; Calle and Casanova, 2008; Riebau andQu, 2005; Chandra, 2005; Chuvieco et al., 1999) for the delineation of forest fire risk zones.
Ajin et al. (2014) demarcated the forest fire risk zones of Idukki Wildlife Sanctuary in Kerala
using RS and GIS techniques. The factors selected are land cover type, distance fromsettlement, distance from road, slope, and elevation. Puri et al. (2011) identified the forest firerisk zones in parts of Northeast India using geospatial tools. Factors such as land use land
cover (LULC), vegetation type, Digital Elevation Model (DEM), slope, aspect, proximity toroads, and proximity to settlements are used to demarcate the fire risk zones. Yunhao et al.
(2007) demarcated the fire risk areas of the Malaysian peninsula. Variables such as fuel typemaps, remote sensing data and meteorological data are used for the study.
The objective of this study is to describe a methodology based on RS and GIS
techniques that demarcates the forest fire risk zones, including their classification dependingon their sensitivity to forest fires. In order to generate the forest fire risk zone map, fiveimportant influencing factors viz. land cover type, slope, distance from settlement, distancefrom road, and elevation are selected. For the delineation of fire risk zones, the Fire Risk Index(FRI) method is used.
1.1. Study Area
The present study area is represented by the Chinnar Wildlife Sanctuary (WLS), a uniqueprotected area located in the Idukki district of Kerala state in south India. The Chinnar WLS,
with a total area of 90.44 sq. km, lies between 10˚15’0” and 10˚22’0” N latitudes and 77˚6’0”
and 77˚16’0” E longitudes. This WLS is bounded by the state of Tamil Nadu to the north, east,and west, Eravikulam National Park to the southwest, and Munnar forest division to the south.
In this area, the temperature varies from 12˚C to 38˚C; and the annual average rainfall is only
500 mm, as it is located in the rain shadow regions of the southern Western Ghats. This area
has a large variety of ecosystems. The major thorny scrub species in the WLS are Acaciaarabica, Acacia leucophloea, Acacia concinna, Prosopis juliflora, and Opuntia dillenii; Dry
deciduous species include Santalum album, Anogeissus latifolia, Terminalia arjuna,
Tamarindus indica, Pongamia glabra, Dalbergia latifolia, Tectona grandis, Lagerstroemia
lanceolata, Cassia fistula, Terminalia bellirica, Emblica officinalis, etc. The common animals
found are Elephant, Crocodile, Gaur, Tiger, Sambar deer, Common langur, Bonnet macaque,
Hanuman monkey, Nilgiri tahr, Grizzled giant squirrel, etc. The study area map is shown inFigure 1.

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Figure 1: Location of the Study Area

2. Materials and Methods
The study area was delineated from the Survey of India (SOI) toposheets (58 F/3, 58 F/7, and58 F/8) of 1:50,000 scale. In order to generate and prepare the thematic maps, ArcGIS 9.3
and ERDAS Imagine 9.2 software tools were used. The land cover type map was preparedfrom the IRS-P6 LISS-III image of 23.5 m resolution. ERDAS Imagine software was used forthe supervised classification of the pre-processed satellite image. The road networks andhuman settlements were digitized from the SOI toposheets and Google Earth. The distancefrom road and distance from settlement maps were prepared from the digitized data using
ArcGIS spatial analyst tools. The contour data was derived from the SRTM DEM of 30 mresolution. The slope and elevation maps were prepared from the 10 m interval contour datausing ArcGIS spatial analyst and 3D analyst tools. The FRI method (Ajin et al., 2014; Ajin etal., 2015) was used for the demarcation of forest fire risk zones. The thematic map layers werereclassified using the Natural Breaks (Jenks) method. Rank was assigned to each class of thethematic map layers, and weight was given to each thematic map layer, according to theirsensitivity to fire or their fire-inducing capability. The index (Table 1) was calculated from theweight and rank (Index = Weight X Rank). The forest fire risk zone map was prepared byoverlaying the index map layers using ArcGIS tools. Finally, the risk zone map was validated
using the forest fire incidence points collected from the records of the Forest Survey of India(FSI).

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Table 1 Rank, Weight, and Index assigned for different factors#Factor1

Land cover type2

Slope (degree)3

Distance fromsettlement (m)4Distance from road (m)5Elevation (m)Class
Water body
Plantation
Evergreen forest
Deciduous forest
Grassland0 – 10.03
10.03 – 19.01
19.01 – 27.72
27.72 – 39.08
39.08 – 67.33
0 – 868
868 – 1619
1619 – 2604
2604 – 4083
4083 - 5983
0 – 407407 – 900
900 – 1580
1580 – 2600
2600 – 4334
440 – 731
731 – 1032
1032 – 1377
1377 – 1806
1806 – 2360

Rank1234512345543215432112345Weight103221Index
10203040503691215108642108642123453. Results and Discussion
In order to have a precise evaluation of fire problems in this area and to take good decisions, itis very important to have a fire risk zone map. A forest fire depends on many factors, whichhave different influences. Each factor plays a significant role in the process of ignition andspreading of fires.
3.1. Land Cover TypeThe physical materials like trees, grass, bare ground and also water body located at thesurface of the earth form the land cover. The land cover type has an important influence in theforest fire behaviour. In contrast to the areas covered with moist and sparse vegetation, thedry and dense vegetation areas are more susceptible to forest fires. The land cover types
found in this study area are grassland, deciduous forest, evergreen forest, plantation, andwater body. In this sanctuary, the areas more prone to forest fires are those covered withgrassland and deciduous forest. Most of the grasslands are located in the western part of thearea, whereas the deciduous forests are mainly found in the central and eastern parts. Theland cover type map is shown in Figure 2.

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Figure 2: Land Cover Type3.2. Slope
Slope represents another very important factor that can induce forest fires and influences thefire behaviour. Fire moves most quickly up slope and least quickly down slope (Rothermel andRichard, 1972). In steeper slopes the rate of fire spread might rise, since flames are angled
closer to the ground surface and the effects of the wind can supply the process of heat
convection (Zhong et al., 2003). Wind currents move uphill and thus the rate of fire spreadincreases with slope steepness. Thus the fire spreading is more in the areas with steeper
slopes. The slope of this study area is grouped into five classes, viz. 0 – 10.03˚, 10.03 –19.01˚, 19.01 – 27.72˚, 27.72 – 39.08˚, and 39.08 – 67.33˚. The slope map is shown in Figure
3.

20Figure 3: Slope

3.3. Distance from Settlement
The chance of forest fire is higher in the areas closer to the human settlements. The tribals ortourists staying in the forests can cause fires intentionally or unintentionally. Fire set by thepoachers to encroach upon forest land, fire set by the tribals to collect Non Timber Forest
Products and to clear forest path, and the fire set by timber smugglers to conceal the stumps
of illicit felling can cause intentional forest fires. Sometimes the fire set by tribals as a part oftheir traditions/customs also can result in fires. Accidental forest fires can happen from the fire
set to drive away wild animals, from recklessly thrown lighted cigarette butts, and also whileburning the agricultural residues. The tourists staying in the temporary shelters can cause
accidental fires, mainly from the unextinguished fire woods left after cooking food or after
campfires. Depending on the distance from settlements, the study area is grouped into fivedifferent classes viz., 0 – 868 m, 868 – 1619 m, 1619 – 2604 m, 2604 – 4083 m, and 4083 –5983 m. The distance from settlement map is represented by Figure 4.

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Figure 4: Distance from Settlement

3.4. Distance from RoadAnother important factor in causing forest fires is the roads near and within the forests. Forests
closer to the roads are more prone to fires, because the villagers and tourists travellingthrough these roads can cause fires, mainly due to unintentional reasons. The carelessly
thrown unextinguished cigarette butts or match sticks, fire released during the heating of coaltar for road construction, etc are the causes of unintentional forest fires. Depending on thedistance from roads, the area is grouped into five classes viz., 0 – 407 m, 407 – 900 m, 900 –
1580 m, 1580 – 2600 m, and 2600 – 4334 m. The distance from road map is shown in Figure
5.

22Figure 5: Distance from Road

3.5. Elevation
Elevation is a crucial topographic factor that is associated with wind behaviour, has a largerole in fire spreading. The areas with a higher elevation located in the western parts of thesanctuary are more prone to forest fires. These areas are more exposed to the prevailingwinds. Due to orographic convective air movement, warm air during day time move in theuphill direction. Also the number of lightning strikes and related ignitions are more in areas ofhigher elevation. The elevation of the area is grouped into five different classes viz. 440 – 731m, 731 – 1032 m, 1032 – 1377 m, 1377 – 1806 m, and 1806 – 2360 m. The elevation map isshown in Figure 6.

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Figure 6: Elevation

3.6. Fire Risk Zones
The forest fire risk zone map of the study area is prepared by combining the index map layersof the selected factors viz., land cover type, slope, distance from settlement, distance fromroad, and elevation using GIS tools. The study area is divided into five risk zones viz. very low,low, moderate, high, and very high. Depending on their fire inducing capability, there wereassigned different weights to the influencing factors. Highest weight has been assigned to land
cover type, because vegetation has the greatest influence in forest fire support. The second
highest weight has been given to slope, because slopes contribute to convectional preheating
and, easy ignition and spreading of fire. The risk zone map is validated with the fire incidence
points for the last 11 years (2005 – 2015) collected from the FSI. The result shows that out ofthe 13 forest fires, 10 (76.92 percent) occurred in the high and very high risk zones, 2 (15.38percent) occurred in the moderate risk zone, and 1 (7.69 percent) occurred in the low and very
low risk zones. The forest fire risk zone map is shown in Figure 7. Most of the fire incidence
points fall spatially near the roads and settlements, which points out a human induced origin;intentionally or unintentionally. The area of each risk zone is calculated and is shown in Table
2.

24Figure 7: Fire Risk Zones

Risk Zones
Very Low
Low
ModerateHigh
Very High

Table 2 Area of Fire Risk Zones
Area (sq. km.)
0.67
28.29
34.21
18.34
8.89

4. Conclusion
In the present study, factors such as land cover type, slope, distance from settlement, distanceto road, and elevation are used for the risk zone mapping. Based on the risk, the area isgrouped into five different zones ranging from ‘very low’ to ‘very high’. Result shows that mostof the fires occurred in the areas closer to the settlements and roads; this fact suggests thatforest fires are induced by people, in an intentionally or unintentionally way. Therefore the very
high, high and moderate fire risk zones are areas which need immediate precautionary
measures to prevent fires in future. The result of this study is validated using the fire incidence
points, which confirms that 76.92 percent of the forest fires occurred in the high and very highrisk zones. Fire risk models are very useful in planning the infrastructure, main roads,
25subsidiary roads, inspection paths, etc, leading to a reliable communication and transportsystem to efficiently fight against small and large forest fires. These maps provide valuable
information for taking precautionary measures to reduce forest fire risk and hence for theenvironmental protection of forests. The final risk zone map will help the forest fire managers
to easily identify the risk zones and to plan better forest management.
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