DIGITALNA ARHIVA ŠUMARSKOG LISTA
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|ŠUMARSKI LIST 7-8/2020 str. 73 <-- 73 --> PDF|
When the visibility map of the asphalt road line was overlapped with the visibility map of the towers, it was found that 123 656 ha of forest area that had not been visible before from the towers or outside the detection range became visible. Thus, people using the roads contributed to the lookout system by 11% and ensured that 70% of the forest area in this region was visible when combined with the towers. On the other hand, 59% of 523 thousand hectares of forest land that were not visible from the roads were visible from the towers. Therefore, fire lookout towers are still the primary lookout structure for this region.
The efficiency/effectiveness/performance of the fire lookout towers is measured through the area that the towers can scan-view. Therefore, towers are supposed to be able to view an area that is scanned at 360-degree horizontal angle and minimum 120-degree vertical angle. Furthermore, the distance that can be viewed with optical devices such as binoculars is also taken into account. In this study, the scanning radius of the fire lookout towers was selected as 18 km. This value is the basic standard used by the Turkish State Forest Authority for the construction of towers (Çanakçıoğlu, 1993). The studies in the literature show that this scanning radius is an acceptable value. Rego and Catry (2006) calculated the effective detection radius for Portugal as 13.4 km for bad weather conditions and 20.6 km for good weather conditions. In America, effective detection range is usually 13-32 km. Especially in north America, the standard effective detection range is 24 km while it has been reported that 10-13 km detection radius could be used in areas with low range of vision in the south and southeast America (Davis, 1959; Brown and Davis, 1973). According to the United States Department of Agriculture (USDA), the observation radius of around 800 towers constructed in 1938 in the north of America was above 30 km on average. In Spain, the effective detection radius was reported to be 6-8 km for bad weather conditions and 10-20 km for optimal conditions