Simulating the spread of fire using the fire surface simulation model (FARSITE) (case study of forests in Neka city)

Dissertation for MSc

Remote Sensing and Geographical Information System - Water and Soil Resources

Abstract

One of the problems in the management of pastures and forests in the northern regions of the country is fires that cause heavy environmental and financial damages. Fire risk management in connection with preventive measures can protect the natural environment from many losses caused by fire. An area of ??natural areas that may catch fire as a result of the start of a fire is an issue that has received less attention. Therefore, the current research tries to present a new method in the field of zoning natural areas in terms of the risk of spread and extent of fire. In order to simulate the rate of spread and the area affected by fire in this research, the FARSITE model was used, which is a vector model for investigating the behavior and spread of fire. The combustible material model was determined as one of the main elements in the simulation according to the vegetation conditions of the area. Local changes in wind speed and direction that occur as a result of the topographical conditions of the area were modeled and used in FARSITE. Also, in order to evaluate the FARSITE model in simulating the spread of fire in the study area, a case of fire that occurred in the area was used, and the accuracy obtained using the Kappa index is 42%. Comparison and analysis of simulated fire with real fire shows that the FARSITE model has the ability to simulate potential fires in the natural areas of the region. Therefore, the zoning process includes several simulations of the spread of potential surface fires. Comparing the final result of zoning with existing fire records indicates the compatibility of such maps with existing reality.

Keywords: forest, fire, combustible material model, FARSITE, Neka city

1) Chapter 1: General research

1-1) Introduction

Natural resources are considered as the wealth of every society and a trust for future generations. Those who use this wealth and divine gift are obliged to use it correctly and according to principles and hand it over to the next generation. Because today it has been proven that natural resources are the bed of life for all living beings and their prosperity and greenness are a sign of the progress of societies and the basis of sustainable development. Forests and pastures, as part of natural resources and also being considered as the most important renewable resources, will never be finished if they are not protected by humans and humans do not provide the basis for weakening or destroying them. Regarding the direct and indirect effects of forest and pasture areas, it is possible to produce and preserve soil, produce industrial and pharmaceutical products, feed underground water, produce oxygen, prevent floods, resort values, preserve animal species and wildlife, and so on. He pointed out that humans and other creatures benefit from it.

However, various factors play a role in the field of forest destruction, including cutting down trees, turning the forest into agricultural land, excessive livestock grazing, pests and diseases, and fire. In the meantime, fire has a special sensitivity to other destructive factors, because even a limited fire can cause considerable damage.

Every year, a large area of ??the world's forests are caught in fire, which not only destroys the vegetation in the fire area, but also disrupts the hydrological processes, increases soil erosion and runoff production in these areas.

Therefore, determining areas with high risk of fire, as well as identifying and predicting the behavior and movements of potential and actual fires in order to prevent possible terrible fires and their spread in susceptible areas, seems absolutely necessary and necessary, which is a difficult and costly task using experimental and field methods. For this reason, the use of new methods and technologies can be considered a suitable alternative to traditional methods. Among these, we can mention geographic information systems and remote sensing technologies.

In this regard, the development of geographic information systems has greatly contributed to predicting and modeling the behavior and spread of fires in natural areas.. Because as it can be seen, in addition to being affected by vegetation density, forest fires are related to other factors such as humidity, altitude, cover type, slope, proximity to cities, villages and roads, all of which can be easily modeled in the geographic information system. Also, if there is comprehensive and sufficient information on the influencing factors, it is possible to use spatial analysis methods in the GIS environment to determine high-risk areas and classify these areas from the perspective of the degree of riskiness against the spread of fire.

Temporal and spatial changes of the spread and behavior of fire can be predicted using physical, semi-physical and experimental models developed in recent years. Among these models, we can mention the fire surface simulator model (FARSITE [1]), which is actually a semi-physical model in the field of modeling the behavior and movement of fire.

FARSITE is a GIS model based on a two-dimensional fire spread simulator that was designed and developed by the United States Forestry and Agriculture Organization and basically for the planning and management of fires in natural areas (Finney, 2004). This model is able to calculate the movement and behavior of the fire in the desired environment and determine the spread of the fire front over time and taking into account the changes in weather conditions in time and space. This model uses spatial information related to topography, flammable materials, and the climate of the region.

This model can be used from several perspectives (Gazmeh, 2013):

To train firefighters before a fire and use computer simulation to better understand fire behavior. Unfortunately, we have witnessed many times that firefighters and foresters were caught in the fire trap, just because they did not know the direction and how the fire spread. Having enough information in this field, necessary precautions and safety issues will be well taught to rescuers.

To assign forces and facilities at the right time and place. The managers and planners of forests and pastures, with a suitable and efficient model in hand, will definitely have the best performance and behavior during fires. The availability of such maps helps managers in the field of identifying high-risk areas in terms of the probability and extent of fire and provides great help in fire extinguishing operations. 1-2 Statement of the problem and the necessity of research Forests are one of the vital forms that are able to continue living directly under the influence of environmental factors. However, natural and artificial destructive factors can have a positive or negative effect on its natural process and cause changes in this dynamic and self-regulating ecosystem, one of which is the phenomenon of fire (Makhsandeh and Mohajer, 2013).

Fires of forests and pastures are one of the main concerns in many parts of the world, not only from an environmental point of view, but also from an economic, social and security point of view (Silvia, et al., 2010) and it is considered as one of the most destructive factors of creating adverse changes in forest ecosystems in the short term (Coban, 2010). In this regard, how to prevent forest and pasture fire damage is very important, and in this regard, it is possible to manage fire suppression through fire risk assessment, predicting the behavior and spread of forest fire based on simulator models.

Increasing consumption of fossil fuels in recent decades has had consequences, including the increase of greenhouse gases in the atmosphere, which has caused changes in the global climate. is One of the most important effects of this climate change is its effect on the occurrence of drought and its intensity and duration. One of the consequences of the drought phenomenon is its influence on the fire process of pastures and forests, so that when the amount of humidity decreases due to the lack of precipitation and the increase in temperature, the ground will be prepared for the occurrence of fire in these areas. Therefore, in order to reduce the damages caused by this phenomenon, it is necessary to carry out comprehensive studies to predict high-risk areas and preventive measures and provide solutions to reduce the damages caused by it. Therefore, fire management can be considered as a solution to prevent damage beyond the power of these ecosystems and its dire economic and social results.