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ŠUMARSKI LIST 5-6/2020 str. 58     <-- 58 -->        PDF

million ha of forest land is classified as first degree fire sensitive forests (GDF, 2012). The average number of forest fires is over 2000 per year and about 12000 ha of forest land is impacted after fires (Sivrikaya et al., 2014). According to fire statistics between 1973 and 2009, about 172,000 ha of forest land has been destroyed as a result of 174 large forest fires (i.e. >300 ha of burned area). The highest number of large fires occurs near the city of Muğla, followed by Balıkesir, Antalya, İzmir, and Adana (Ertuğrul and Varol, 2016).
To prevent large forest fires and forest fires in general, the firefighting team should arrive at the fire scene as quickly as possible so as to increase the probability of controlling the forest fire (Akay et al., 2012). In order to minimize damages caused by the forest fires and the cost of fire extinguishing activities, it is important to detect forest fires as early as possible and inform firefighting teams immediately for fire control (Mascaraque et al., 2007). The most effective way for an early detection of forest fires is by systematically locating fire lookout towers and monitoring fire sensitive forestlands that are visible from these towers (Millan-Garcia et al., 2012; Yuan et al., 2015).
During the fire season in Turkey, the General Directorate of Forestry establishes fire lookout towers where fire watch personnel monitor forests continually and maintain communication with firefighting teams (Gülci et al., 2016). Fire lookout towers are located at the highest points that are generally on ridges where large forestlands can be seen by fire watch personnel. Thus, fire lookout towers should be carefully located in such a way that ensures fire lookout personnel are able to monitor as much forest land as possible in the region.
In recent decades, Geographical Information System (GIS) techniques have been used in monitoring forest fires, generation of fire risk maps, and in development of firefighting strategies (Vipin, 2012; Sivrikaya et al., 2014). In determination of the areas that are visible from specified sets of locations, viewshed analysis has been effectively used in GIS technologies based on a profile extraction method (Singh et al., 2014). In a study conducted by Akbulak and Özdemir (2008), visibility analysis was implemented to investigate forest lands that are visible and not visible from fire lookout towers in the Gallipoli Peninsula in Turkey. They reported that most of the area consisted of coniferous forest that cannot be seen by the current lookout towers. In a similar study, GIS and remote sensing techniques were used to evaluate suitability of fire lookout towers considering fire risk zones (Korale et al., 2009). Pompa-García et al. (2010) suggested that visibility analysis with a digital elevation model (DEM) should be combined with a vegetation cover map. They found that visibility effectiveness of the current lookout towers was about 43% which indicated that more than half of the forest land in the study area was not visible by the lookout towers. In a recent study, GIS techniques were implemented to evaluate visibility capabilities of fire lookout towers in a study area located in north of Turkey with Mediterranean-like climate (Kucuk et al., 2017). The authors suggested that additional fire lookout towers were needed in the area since some of the current lookout towers were not functioning properly. In another study, visibility of forest lands was examined by fire lookout towers in the city of Dalaman in Turkey (Göltaş et al., 2017). As a result of the study, it was found that only 47% of forest lands could be monitored by fire lookout towers.
In cases where the locations of the lookout towers are not suitable to monitor forest lands in a specific area, alternative lookout towers can be considered to improve the percentages of visible forest lands. In the consideration of suitable locations for new towers, it is important to evaluate defined criteria about the candidate points before visibility analysis. Such complex problems involving determination of optimal site locations can be solved by using a GIS based suitability analysis approach. Suitability analysis can be used to generate new data sets from existing data, reclassify data to detect areas with high suitability, and combine the data into one final result of optimal suitability (Koikai, 2008). There are various examples of suitability analysis in the field of forestry (Gülci and Akay, 2015; Quinta-Nova et al., 2017), however, there are a limited number of studies that attempted to search for potential fire lookout towers based on specific factors. These factors may include proximity to road network for easy access, minimum elevation to be able to see large forest lands, low ground slope for proper construction, and topographical form of the point (i.e. ridges) to ensure 360° angle of vision (Harvey, 2015).
In this study, the forested lands that can be seen by the lookout towers in Köyceğiz FED of Muğla Forestry Regional Directorate were examined using visibility analysis in ArcGIS 10.4 software. Besides, locations for additional towers were determined by using GIS based suitability analysis in order to extend the visible forest lands by the lookout towers. Therefore, the distinct contribution of this approach is that not only the visibility capabilities of new towers were investigated but also suitability of the tower locations was examined in Mediterranean region forests that are highly sensitive to wild fires.
Study Area – Područje istraživanja
This study was conducted in the border of Köyceğiz FED in the city of Muğla within the Mediterranean region of Turkey. The Köyceğiz FED is located at 36°46´53´´