| Forest fire is a significant ecosystem disturbance that not only destroys the ecosystem but also negatively impacts on human living conditions resulting in significant economic losses.In order to objectively understand the level of forest fire risk in various regions of Macheng and effectively carry out fire prevention work,this study analyzed historical forest fire data of 2011-2021,data of meteorology,topography,and social infrastructure to explore the spatial and temporal distribution of forest fires of the region.Field surveys were carried out to obtain data on fuel load combustibility.A total of 15 factors were selected from four aspects: combustible material,topography,meteorology and human factors as fire risk zoning indicators,so as to provide scientific reference for the zoning of forest fire prevention and control in Ma Cheng.The main research conclusions are as follows:(1)The spatial and temporal distribution patterns of forest fires in Macheng were investigated,and the characteristics of the occurrence of forest fires at different scales,such as annual,monthly and hourly,were studied in time,and the distribution of forest fires across administrative units was analysed.The results show that fires in Macheng varied considerably between 2011 and 2021,occurring mainly in March and April in spring and January and February in winter,and between 11:00 and 15:00 during the day;the spatial distribution of forest fires was uneven,mostly located in the southeastern edge of Ma Cheng and the central strip.Muzidian Town,Sanhekou Town and Huangtugang Town were frequent forest fires,while the western areas of Macheng had fewer and scattered forest fires.(2)An analysis of the relationship between the occurrence of forest fires and external influencing factors shows that in terms of meteorological factors,when the temperature was below 15℃,forest fires increased with the rise in temperature,but when it was above 15℃,forest fires gradually decreased;When the relative humidity was below 55%,forest fires were prone to occur,but humidity was greater than75%,forest fires were difficult to occur;Precipitation had a strong inhibitory effect on the occurrence of forest fires;When the wind speed was less than 3 m/s,the increase in wind speed promoted the occurrence of forest fires,but when the wind speed was greater than 3 m/s,forest fires gradually decreased.In terms of terrain factors,the increase in altitude was not conducive to the occurrence of forest fires;When slope was less than 15°,the increase of slope promoted the occurrence of forest fires,but when the slope was greater than 15°,the increase of slope inhibited the occurrence of forest fires;The sunny slope was more prone to forest fires than the shady slope.In terms of human factors,when the density of residential areas was very small or very large,forest fires were less likely to occur;Forest fires first increased and then decreased as the distance from the residential area increased.When the distance was between 0.5 to 1 kilometer,forest fires were most likely to occur;The closer to the fire source,the more likely forest fires occurred.(3)Through field sampling,indoor measurement,and Arc GIS interpolation method,combustible data in Macheng forest region were obtained.The results show that the fuel load ranged from 0.95 t/ha to 16.02 t/h.The fuel load was high load in the central inverted " V " zone of the northern and southeastern regions.Areas exceeding 8 t/ha accounted for14.82% of the total forest area.The continuity index range was 0.02-0.88,and from the overall distribution,it was generally high in the north and low in the south.About 47.56%of the forest land continuity index was between 0.4-0.6,and areas above 0.8 only accounted for 0.62% of the total forest land area.The moisture content ranged from11.43% to 26.12%,with areas with lower moisture content(<16%)mainly located in the eastern and southeastern parts of Macheng,and 57.03% of the forest land had a moisture content of 16% to 18%;The ignition point ranged between 204.65℃-298.2℃,with lower ignition points in the northern and western regions.Areas below 240℃ accounted for14.33% of the total forest area,and 74.48% of the forest area had ignition points between240℃ and 270℃;The calorific value ranged between 13.12 k J/g-20.85 k J/g.The northern and central inverted " V " zone,as well as the southwestern edge areas,had higher calorific values,but only 5.44% of the forest land had a calorific value greater than19.5 k J/g,and 91.19% of the forest land had a calorific value of 16.5 k J/g-19.5 k J/g.(4)Based on the forest fire risk index,the natural break point method was used to zone the fire risk in the study area,which was divided into five types of fire risk zones,very high,high,medium,low and very low.The zoning results show that most of the study areas had high forest fire risks,with moderate and above grade fire risk areas accounting for approximately 75% of the total forest land area.The high risk and very high risk zones were mainly located in the northern area and the central inverted " V " zone.Fire risk was extremely high in the central and western part of Futianhe Town,the northern part of Songbu Town,the southern and northwestern part of Huangtugang Town,the western and southwestern edge of Sanhekou Town and the central and southeastern part of Guishan Town.The very low fire risk area only accounted for 9.66% of the forest area,except for a scattered distribution in the northwest,mainly distributed in the northeast of Macheng.Based on the above findings,we proposed the following measures to prevent and control forest fires in Macheng: strengthen patrols and focus on the central inverted " V " zone and the northern area,where the fire risk is high,during the period from January to April and from November to 15.The fire prevention and control measures include:enhancing people’s awareness of fire prevention through publicity,strengthening the management of man-made fire sources,and curbing forest fires at source,focusing on the regulation of combustibles in areas with strong flammability of surface combustibles improving a high-precision,multi-level fire prevention and monitoring system,and building a professional firefighting team to effectively improve fire prevention and disaster relief capabilities. |
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