Rules for the construction of firebreaks along public roads in selected European countries

Firebreaks are one of the protective measures used to safeguard forests in the event of fire. Their purpose is to limit the possibility of fire spreading. They are usually created in places where there is a risk of fire, for example, near communication routes, military training areas and industrial plants located in the forest or in its immediate vicinity. Belts are also used to divide large forest complexes into smaller ones, limit losses in large fires and create lines of defence during rescue operations.

At the beginning of the 20th century, firebreaks began to be established in Europe, initially along railway lines, which posed a high fire risk to forested areas. Subsequently, the principles for establishing belts along linear infrastructure changed. The first studies in Poland on firebreaks were conducted at the Forest Research Institute in the mid-1960s. This included work on modernising the belt system as part of the development of methods to prevent the spread of forest fires (Karlikowski and Łonkiewicz 1966) and on modifying the implementation of Kienitz belts along railway lines (Karlikowski and Łonkiewicz 1969). In the early 1970s, an assessment of the usefulness of first- and second-order belts, carried out by Karlikowski and Łonkiewicz (1971) on the basis of several years of research, was of great practical importance. This proposed principles for the management of belts to make them an effective biological fire barrier through an appropriate selection of species, including biocoenotic admixtures, creating good living conditions for birds and animals and ensuring productive use of the area. Another evaluation of the effectiveness and extent of the use of firebreaks as a means of preventing the occurrence and spread of forest fires was presented in 1983 (Karlikowski et al. 1983). The study, which covered the years 1975–1982, showed that forest fires near public roads accounted for 24% of all fires and covered 18.6% of the total area burned. In contrast, fires near railway lines accounted for 17.2% (in terms of numbers) and 20.3% of the area burnt.

Currently, in Poland, according to the Regulation of the Minister of Internal Affairs and Administration of 7 June 2010 on Fire Protection of Buildings, Other Structures and Land (Journal of Laws No. 109, item 719), forests adjacent to facilities that may pose a fire risk to the forest are separated from these facilities by fire protection belts, which are maintained in a condition that ensures their year-round usability. The regulations of the Minister of Environment (Journal of Laws No. 58, item 405) and the Minister of Infrastructure (Journal of Laws 2020, item 1247) distinguish five types of firebreaks (types A, B, BK, C and D), which are established near public roads, railway lines, storage and public utility facilities, industrial facilities, military training areas and to separate large, dense forest areas. The obligation to create and maintain firebreaks lies with the land managers. In 2022, there were a total of 14,475 km of firebreaks in state forests, of which 77% were firebreaks next to public roads (7,621 km) and railway lines (3,550 km) (Wysocka 2023). The cost of maintaining belts next to public roads in state forests is almost 7.5 million zloty per year, while the losses caused by forest fires next to roads are estimated at tens of thousands of zloty.

Between 1981 and 1990, rail transport was the cause of 5.92% of forest fires and road transport was the cause of 0.56% of forest fire incidents in Poland. In the following decades, a decreasing trend of this phenomenon was observed, as between 1991 and 2000, 2.1% of fires occurred along railways and 0.48% along roads. In the following decade, these were 0.81% and 0.34% of the total recorded forest fires, respectively (Szczygieł 2016).

From time to time, the principles of maintaining fire belts need to be evaluated in terms of the suitability and effectiveness of this passive way of protecting forests from fires, analysing the changing factors that pose a threat while ensuring an optimal level of safety, also taking into account the economic calculation. The project commissioned by the General Directorate of the State Forests, entitled ‘Analysis of the Justification for the Establishment of Type A Firebreaks from a Safety and Economic Point of View’, examines whether it is justified to keep a belt adjacent to the boundary of a road lane devoid of dead tree parts. As a prelude to this assessment, a review of the principles of firebreaks adjacent to public roads in other European countries was carried out, the results of which are the subject of this paper.

Under the current Polish law, forest managers are currently required to establish a Type A firebreak (Fig. 1). This is a 30-m-wide belt of land adjacent to the boundary of a road lane or facility and free of dead trees, lying branches and fallen trees (§ 10(1)(1) of the Regulation of the Minister of Environment of 22 March 2006 on the Detailed Principles of Forest Fire Protection; Journal of Laws of 2006, No. 58, item 405, as amended). Also, according to Section 39 (1) of the Regulation of the Minister of the Interior and Administration of 7 June 2010 on the Fire Protection of Buildings, Other Structures and Land (Journal of Laws of 2010, No. 109, item 719), it is prohibited to deposit, in particular, branches, brush-wood, unkempt felled trees and post-mining waste at a distance of less than 30 m from the edge of a railway track or a public road, with the exception of roads with an unpaved surface. The deposit of these residues in the form of banks and heaps is not permitted. The Type A belt separates the forest from public roads, access roads that are not public roads – from an industrial or storage facility, storage facilities and public utilities. The vast majority of these belts are realize by the forest department. According to the provision of section 38(3) of the above-mentioned regulation, if a forest area: –

is classified as Category III forest fire danger,

Figure 1.

It should be noted that forest owners, managers or users whose forests alone or together form a forest complex of more than 300 ha are obliged to maintain firebreaks.

No information was found in the literature on regulations for the creation of firebreaks along public roads in European countries. There are also no European Union (EU) directives in this area, and knowledge about the requirements for the installation of firebreaks is not widespread. For this reason, individual European countries were asked to indicate the applicable standards for the installation of firebreaks along public roads. The range of information received is not uniform and is partly due to the fact that each country has a different emphasis on the issue of protecting forests from fires along public roads. Guidelines for the establishment of firebreaks in selected countries are presented below.

Spain

In this country, there is no clear national legislation on firebreaks along roads. Spain is divided into 17 autonomous regions, each of which implements measures to protect against forest fires. In the Valencia region, for example, there are three types of recommendations on fire protection, dealing with the following issues: forest roads, water points and technical regulations for the division of the forest area, so that firefighting is possible (Baixauli et al., 2015). The last document describes in detail the firebreaks that are created on the forest plots. Their density and arrangement depend on the size of the forest complex, the terrain and other factors. The measures taken consist of creating a firebreak in which the vegetation is removed over a certain width down to the mineral layer. From this belt, intensive vegetation reduction is carried out on two sides, gradually decreasing as the distance from the mineral belt increases. For forest roads and public roads, the same type of firebreaks applies, as shown in Figure 2 (Baixauli et al. 2015).

Figure 2.

Twenty-one European countries were asked to provide information on the rules for creating and maintaining firebreaks along public roads, primarily using contacts with national representatives who are members of the EU Expert Commission on Forest Fires. Countries where forest fire risk is minimal were omitted. Feedback was received from 19 countries.

The information provided shows that these countries approach the fire protection of forests along public roads in different ways, mainly due to the fire risk assessment along roads crossing forest complexes and the general forest fire risk in the respective country. Figure 3 shows the average annual number of forest fires that occurred between 2011 and 2020 in the countries that responded to the question about firebreaks along public roads. The data was compiled based on the European Forest Fire Information System (EFFIS).

Figure 3.

In six countries (the Czech Republic, Finland, the Netherlands, Norway, Serbia and Sweden), belts along roads in forest complexes are not established at all due to lack of danger. In the remaining 13 countries, belts are established either in the form of a mineralised belt or a cleared belt of materials particularly susceptible to ignition and fire, or methods combining both are used.

The essence of creating a mineralised furrow is to create a barrier that is completely free of combustible material to prevent the spread of fire. Its effectiveness depends primarily on the width of the mineralised furrow and the burning intensity of the materials in front of the furrow, as well as on the height of the fire zone, which is influenced by the type of vegetation and meteorological conditions. Therefore, such a belt should be established as close as possible to the edge of the path to prevent intense burning, which increases the risk of fire metastasis beyond the mineralised belt. In general, the lower the amount of combustible material in front of the firebreak (e.g. due to mowing of the roadside) and the greater the width of the furrow, the greater the barrier effect of the belt for a fire in the germination phase. If there is tall grass and shrub vegetation, especially dry vegetation, both in front of and behind the mineralised barrier, it will not be an effective barrier in the event of a developing fire even if the ground is free of vegetation over a width of several metres. This is illustrated by the examples of large-scale forest fires in Poland in Kuźnia Raciborska (approx. 9,000 ha) (Jopek 2016) and Potrzebowice (5,600 ha) in 1992 (Szczygieł 2016), when mineralised belts of 2 m width were not able to contain a developed fire that had started next to a railway embankment about a few metres from the mineralised belt at both sites.

On the other hand, the establishment of firebreaks in the form of cleared land of combustible material that could potentially pose a hazard (e.g. undergrowth, brush, undergrowth, lying branches, tall herbaceous vegetation, etc.) is intended to limit the speed of fire spread and its intensity. This is due to the limited amount of combustible material. These belts are wider than the mineralised belts and vary in size from a few metres to several tens of metres.

Simple mineralisation belts are established in Lithuania, Ukraine, Germany, Romania and Bulgaria, among others, and their width varies between 1 and 6 m. The relatively small number of countries ordering only this type of protection may be due to the low evaluation of the effectiveness of mineralisation belts and also the difficulties and costs of mineralisation on site. In nine countries (Bulgaria, Latvia, France, Portugal, England, Romania, Italy, Switzerland and Ukraine), belts are established in the form of a cleared area next to a public road running through or in the immediate vicinity of a forest. The width of the cleared belt varies and ranges from 2 m (Italy) to 30 m (France). The most detailed regulations for clearing belts are in France and Portugal, where their implementation is based on the local fire risk and the type of road (motorway, national road, municipal road, which should be understood as traffic volume) or its importance in the forest fire protection system of the area, as defined in the fire protection plan (Portugal). In Spain, firebreaks are established not only along public roads and forest roads, but also, depending on the size of the complex, in compact complexes that are not crossed by roads. These are the countries with the highest forest fire risk, which is also shown in Figure 3. In England, the width of the cleared belt depends on the height of the stand and can be up to three times the height of the adjacent vegetation in areas of increased risk. Only in two countries (Bulgaria and Ukraine) are both mineralised and cleared belts of combustible forest fuel established along roads. Firebreaks in the form of cleared flammable forest material are also important from the point of view of organising firefighting operations, as they can facilitate the deployment of firefighting units to prevent the fire from spreading to the other side of the road in the case of low- and medium-intensity fires that spread from deep in the forest, which can also pose a risk to road traffic (Portugal). The obligation to establish both types of firebreaks lies with the manager of the forest (Bulgaria, Lithuania, Romania, Germany) or the road (Latvia, France, Portugal, Ukraine, Hungary). The establishment of a firebreak alone does not guarantee that it will effectively contain a forest fire. For it to be effective, it must be properly maintained, especially during the period of fire danger. As a result, fires sometimes pass through poorly maintained belts because they do not provide a barrier, for example, due to the emergence of tall herbaceous vegetation, which facilitates the spread of fire.

There are no publications in the available literature evaluating the effectiveness of firebreaks as a means of preventing the spread of fires along road or rail routes. National studies state that the average area of a fire along public roads in Poland between 1975 and 1982 was 1.34 ha, while between 1990 and 2002, it was 0.36 ha (Piwnicki et al. 2006). According to a detailed study, fires on firebreaks next to public roads accounted for 0.92% of the total number of forest fires in 2003–2004 (there were 24,093 of them) and their average area was 0.26 ha. At that time, as in previous years, there was an obligation to create a mineralised furrow on the edge of public roads, in addition to clearing the areas, with a minimum width of 2 m at a distance of 2–5 m from the outer edge of the road ditch. Only 60% of the fires broke out in front of the furrow (i.e. it could serve as a barrier to the spread of fire from the outset), but unfortunately, almost half of the fires penetrated through the mineralised zone. This was an indication of the low effectiveness of the mineralised furrow, which could also be due to negligence in the construction of the lane or poor maintenance. This led to a change in legislation and the abandonment of mineralisation of forest soils next to public roads, which was costly and did not guarantee an adequate level of safety (Piwnicki et al. 2006).

Between 2017 and 2021, 11,106 fires were recorded in the national forests, with a burnt area of 3,780 ha. Of these, 768 occurred near public roads, where an area of 55 ha was destroyed. The average area burnt in forests was 0.34 ha, next to roads (0.07 ha). These were mostly fires of ground cover (92%), caused by ignition of the fire, noticed by bystanders (70%) and extinguished quickly (in 77% of the incidents, the fire brigade's intervention time was no more than 90 min) (Szczygieł et al. 2022). The significant decrease in roadside fires can be attributed to the increase in the effectiveness of the fire protection system in state forests and the development of mobile network communication, which makes it possible to quickly report fires noticed by bystanders.

In the absence of Europe-wide regulations on prevention measures to protect forests from road fires, it may be helpful to establish a set of best practices that could be used to amend existing policies in individual countries where means of transport pose a fire risk. However, it is advisable that each country addresses this issue individually, taking particular account of natural and landscape conditions, to best protect natural assets and minimise economic losses.

In Poland, the current requirement to keep a space 30 m from the roadway free of dead plant parts is one of the strictest. In the information provided from other countries, there is more than one reference to keeping, for example, a belt free of woody and shrubby vegetation at a distance from the carriageway, which is not taken into account in the Polish regulations. Other countries also take into account the areas of mowed ditches, the branch-free space above and beside the lane. A review of data on the methods of protecting forest areas next to public roads in selected European countries and a national analysis of the occurrence of fires in their vicinity lead us to take a critical look at our current regulations in this area, not only in terms of ensuring adequate forest fire protection, but also taking into account the economic calculation of establishing Type A firebreaks in their current form.