Abstract

The mitigation of forest fire risks is a high priority for the Portuguese municipality of Mirandela. The municipality performs risk assessments as a basis for targeted mitigation measures that are adapted to the local needs. This assessment includes historical research into past occurrences of forest fires and results in specific actions to reduce the risk and increase resilience.

Introduction

The forest fire risk is one of the main risks of the municipality of Mirandela, Portugal. Forest fires can cause environmental and material damage as well as lead to personal injuries among the population of the affected areas and firefighters. For the mitigation of this type of risk, it is important to have data on previous occurrences, including the number of fires, burnt areas, locations, and causes. Knowledge of such data will allow the definition of susceptible areas. As the previous occurrences are important, so are the physical characterization (hypsometry, slope, hydrography and north-south orientation), climate, population and land cover characterization, allowing a better and deeper knowledge of the risk within the territory. With this information in hand, it is possible to plan specific actions to reduce the risk of forest fire. The forest fires in Mirandela are of type 2, which means that there are a large number of occurrences but a small burnt area. For Mirandela, fire prevention is an absolute priority.

 

Study Area

 

The municipality of Mirandela is located in northern Portugal’s Bragan̤a District, with 30 parishes and an area of 659 square kilometers. Forest fires are one of the main risks in the municipality. Between 2001 and 2012, the average number of fires per year was 92, and in the same period the average of burnt area was 687.61 hectares (ha) per year. As a result, the risk awareness of the population, politicians and emergency services is high.

Therefore, the municipality is developing a strategy to assess and mitigate the forest fire risk. Detailed risk mapping and Earth observation are important for both the risk assessment and local mitigation strategies. Through the European Union’s (EU) INTERREG IVC project MiSRaR, Mirandela has shared these lessons with other European partners. MiSRaRåÊ was a three-year project co-financed by the European Regional Development Fund and made possible by the INTERREG IVC program. The goal of the project was to exchange knowledge and experiences on risk mitigation in spatial policies. The project was a cooperation among seven partners in six EU member states: the Safety Region South-Holland South, The Netherlands; the city of Tallinn, Estonia; the region of Epirus, Greece; the province of ForlÌÂ-Cesena, Italy; the municipalities of Aveiro and Mirandela, Portugal; and the Euro Perspectives Foundation, Bulgaria. The project has resulted in a handbook in which the lessons on the mitigation process are described and best practices from the partners are presented. The lessons from MiSRaR are now being implemented in the PRISMA project (PRomoting and Implementing Strategies for risk Management and Assessment). In the coming year, the Safety Region South-Holland South, the city of Tallinn, the municipalities of Aveiro and Mirandela, and the Stara Zagora Regional Economic Development Agency (Bulgaria) will develop mitigation strategies for their risks with highest priority: forest fire, urban fire and transport of dangerous substances. During spring 2014, the results and lessons will be shared in three international conferences.

Methodology

 

Municipal Plan of Defense ofåÊForeståÊagainst Fires

In Portugal, municipalities are by law required to design a Municipal Plan of Defense against ForeståÊFires, abbreviated in Portuguese as PMDFCI. The main objective is to create a dynamic plan with a forest fire risk reduction policy adapted to local conditions. The PMDFCI is a planning tool which is revised and updated every five years. It is based upon a national methodological guide of the Institute of Nature Conservation and Forest and aims to operationalize at the local and municipal levels the standards contained in the Portuguese national forest fire legislation (Resolution of the Council of Ministers nå¼ 65/2006, 26 May). The plan is divided in three main parts. OneåÊ contains the background information about the risk based on the risk assessment. The second presents the action plan (or mitigation strategy), and the third part is the municipal operational plan, which is updated once every year (Technical Guide for Elaboration of the Municipal Plan of Defense against Forest Fires, ICNF, 2010).

Risk Assessment

For a coherent approach to the problem of forest fires at the municipal level, it is absolutely necessary to execute a risk assessment that characterizes the conditions of occurrence of this phenomenon. Only an exact knowledge about the risk will establish a firm ground for a mitigation strategy that can be cohesive and tailored to the territory particularities. The required background information, which is a specific diagnostic, can provide information for a supported decision. The Technical Guide for Elaboration of the Municipal Plan of Defense against Forest Fires defines background information that consists in:

1. Physical characterization. It starts with a basic insight on the geography of the municipality: hypsometry, slope, hydrography and north-south orientation of slopes. These are the demands for detailed mapping.

2. Climate characterization. The forest fire risk is directly related to climate conditions like air temperature, relative humidity, precipitation and wind speed. For the municipal level, it is enough to analyze these conditions for each month of the year, without any geographical distinction.

3. Population characterization. The forest fire risk is also directly related to the vulnerability of the population. The resident population by census and parish council, the population density, the aging index and its evolution, the population by sector of activity, the rate of illiteracy, and pilgrimages and festivals are all researched to assess vulnerability. This information is essential to make high-quality decisions about awareness campaigns, but also to identify the trend of depopulation in villages. In the long term, depopulation will decrease the effectiveness of a means of forest fire control known as ‰ÛÏfuel management‰Û: keeping the forest clean of dead wood.

4. Land cover characterization and special areas. Both the probability and the potential magnitude of forest fires are related to the land use. Consequently, in the risk mapping of land cover, data on forest areas, protected areas, forest planning instruments and equipment for forest recreation, and hunting and fishing areas are essential.

5. Historical analysis and causes of forest fires. Current understanding of the actual risks of forest fires in Portugal is firmly based upon historical research. Meticulous registration of forest fires has generated excellent insight in the occurrence of fires as well as their annual, monthly, weekly and hourly distribution. These historical analyses into the main causes of forest fires allow municipal interventions to support local needs.

Results and Discussions

Historical analysis

In the municipality of Mirandela, the peak year of occurrences was 2001 with 132 fires. The annual result of these fires was 375.43 ha burnt. The peak year in burnt area was 2003 with 2, 648.36 ha lost due to 85 fires. The monthly distribution in the period 2001-‰ÛÒ2012 shows that largest number of fires and burnt areas occur in August. This results in a great strain on fire brigades during summer vacation. This insight helps to identify targeted prevention and preparation measures.

The distribution of fires over the weekdays shows that most fires occurred on Saturdays. However, more hectares are burnt on Sundays. The inhabitants of Mirandela like to barbecue in nature during the weekends. This explains the larger number of occurrences during the weekend. In the case of big fires or more fires occurring at the same time, very often the fire brigade is not able to have it under control until the next day. Therefore, the larger number of occurrences on Saturdays results in more damages on Sundays. By knowing the main causes and occurrence of fires within the municipality, targeted mitigation and preparation is possible. In this case, the education of inhabitants on fire risks through awareness campaigns and a higher state of readiness of the fire brigades during the weekends in summer proved to be good solutions. The same kind of analysis has in the past resulted in a general prohibition of a kind of firework in forest areas during the critical period [1].

Finally, the hourly distribution reveals that the 4 p.m. hour has the highest probability of fires, resulting in the most burnt areas in the following hour. This information can enhance the vigilance of the fire brigades.

Triggers of forest fires

Another important kind of research is the evaluation of causes or triggers. Specific registration and research in the period 2001‰ÛÒ2012 provided the necessary insight. The largest cause is negligence: 45 percent are caused by small agricultural fires or during forest works. The second largest known trigger is arson: 25 percent of the fires are started intentionally. In this period, only one natural cause (lightning) was registered. For a substantial part of the fires (30 percent), the cause could not be determined. However, these insights help to establish mitigation strategies to prevent the ignition of fires as much as possible.

Mapping

Besides the temporal distribution, the spatial distribution of the forest fire risk is very important in the mitigation process. The Portuguese model for forest fire risk mapping includes three different maps (Technical Guide for Elaboration of the Municipal Plan of Defense of Forest against Fires, ICNF, 2010):

1. The hazard map is the result of the combination of probability (based upon the historical data) with susceptibility (based upon the types of trees), presenting the potential of the territory for the occurrence of the phenomenon. Both the probability and the susceptibility are divided in five classes, from low to extreme.

2. The risk map is a combination of the components of the hazard map with the components of the potential damage (vulnerability and value) to indicate the potential for loss in the face of the phenomenon. The vulnerability and value are defined by the land use. The risk map gives information about the potential loss in every place mapped. This map is particularly useful for identifying preventive measures

3. The defense priorities map is created by combiningåÊ the hazard map and risk map for actual forest fire suppression. They are therefore combined into a specific forest fire defense map. In this map, the suppression priorities are identified: the elements (housing, infrastructure, etc.) that are more important to protect during a fire.

Together, the hazard map, risk map and defense priorities map provide a sound knowledge base for the PMDFCI that guides and justifies the choice of prevention actions.

Action plan

The second part of the PMDFCI is the action plan for the mitigation strategy. The mitigation strategy of the Mirandela PMDFCI consists of actions aimed at:

1. Increasing the resilience of the area to forest fires;

2. Reducing the incidence of fires;

3. Improving the effectiveness of the firefighting;

4. Recovering and rehabilitating ecosystems;

5. Building a functional and effective organizational structure.

The acquired mapping information allows the use of simulation models for fire behavior. Using these simulation models, the exact locations can be pinpointed where forest fire defense infrastructure (such as access roads and water access points) and forest fuel management actions are indicated. Fuel management actions include the manual or mechanical cutting of the forest, chemical treatments to reduce inflammability, grazing by livestock, and prescribed fire (controlled burning of areas). This means that the preparation and mitigation strategy can be tailored to the exact local risk situation, making good use of detailed mapping.

Operational plan

For a better and more effective response from all the stakeholders on the issue of forest fires, it is necessary to establish procedures for the operational situation and define communication channels. Therefore, the third part of the PMDFCI is the operational plan (Technical Guide for Elaboration of the Municipal Plan of Defense of Forest against Fires, ICNF, 2010). This plan is aimed at extinguishing fires before they grow. The operational plan includes protocols for firefighting, chain of command and communication. It also includes arrangements for quick detection of fires and overviews of available resources, both repressive (like firefighting equipment) and preventive (like water accessibility points).

Lessons

The results of risk mapping and risk assessment have contributed to our understanding of the impact of management strategies and can ultimately improve the allocation of firefighting resources. From the implementation of the PMDFCI and risk mapping approach, the municipality of Mirandela has learned some valuable lessons:

– Good incident registration and historical research provide a firm basis for informed policy decisions. With insight regarding temporal and spatial occurrence and causes, specific prevention and awareness measures can be taken.

– For mapping, the use of accurate GIS information and high quality cartography are important success factors. Furthermore, the updating of information has to be guaranteed, because the land use and population variables evolve over time.

– With hazard and risk mapping, the areas burnt in the past, areas with high probability due to surface fire characteristics, and areas with a lot of vulnerabilities can be analyzed. The overlapping of these areas gives direct insight in the high risk areas and thus pinpoints the possible areas for specific preparation and mitigation.

SÌ_nia Gon̤alves is a forest engineer in the Municipal Service of Civil Protection and Forest Technician Office, in the city hall of Mirandela, Portugal. She is local project manager for the European Union’s (EU) INTERREG IVC MiSRaR and EU PRISMA projects.

Ruud Houdijk is a consultant on risk and crisis management in The Netherlands. He is national project manager for regional risk assessment and a member of the committee on national risk assessment for the National Security Strategy. He has participated in the MiSRaR project and is now involved with PRISMA.

 

REFERENCES

[1] Decree-law nå¼ 124/2006, 28 of June with the changes introduced by the decree-law nå¼ 17/2009, 14 of January

 

 

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