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A perspective on sustainable environment

Forest fires in continental Portugal
Result of profound alterations in society and territorial consequences

Les incendies de forêt dans le Portugal continental
Résultat de profonds changements sociaux et conséquences territoriales
Luciano Lourenço

Abstracts

The socioeconomic transformations that occurred in Portuguese society during the second half of the last century have led to a profound change in its age structure, with important repercussions in terms of sectors of activity. This in turn has led to a drastic reduction of workers in the primary sector, due to the rural exodus, a consequence of which was the abandonment of many agricultural areas and their transformation into forested areas.
In turn, the abandonment of the agricultural-forestry-pastoral activity led to an accumulation of large amounts of fuel in the forest which, when weather conditions are favorable, feed forest fires.
With the accelerated abandonment of farming activities-conditions conducive to the development of natural areas-, and with disinvestment in forests, forest fires have been growing increasingly bigger and there seems to have been little success in countering this terrible scourge that is wiping out greater space suitable for forestry.

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Introduction

1One of the areas in which significant evolution was noted in Portugal in the time period defined as the working basis for this issue of the journal, corresponding to the last fifty years, was, without doubt, in the forestry sector, as is recounted in another article published in this issue (BENTO et al., 2018). However, we refer to forest fires not only because they have contributed greatly towards this evolution, but also due to their serious consequences.

2Forest fires are understood here in a much broader sense, as they include fires in scrubland and fallow land, as is the case of natural grasslands, or rather, they correspond to fires that occur in spaces suitable for forestry, although they may not be forested at the time of the fire.

3In this context, this article aims to only describe some aspects related with the phenomenon of forest fires in Portugal, without attempting to be very innovative or creating a referential summary of all that has been written on the causes, behavior and evolution of forest fires in Portugal, as this would imply a more in-depth development of the topic.

4In fact, if we were to delve into historic research, we would have to go back to at least the 15th century, when, on 22 September 1464, King Afonso V published a royal letter in Tentúgal, near Coimbra, in which he proclaimed that:

[...] the request of the city and to avoid the continuation of the great damages caused by the silting of the Mondego, it is forbidden, from Coimbra to Seia, to set fires up to one league from the banks of the Mondego [...]
(Parchment no. 84, of the Parchment Collection of the Municipal Historic Archive of Coimbra, cited by A.
Fernandes Martins, 1940, p. 178-9).

5Besides this, various other ancient documents could be mentioned, but we simply cannot resist mentioning a work by Federico Warnhagen (1836), General Manager of Leiria Pine Forest, where pioneering work was undertaken, like the start of the planning of this Forest, which was almost totally burned in 2017, or the realization of the first controlled fires in living memory, as they are “[...] a safe means of preventing it from burning in the summer [...]”.

6Among more recent references, relating to the period under study, the oldest that we know relates to a small booklet called: Fire, scourge of the woods, with only 27 pages, published in September of 1966, in a photocopied edition, by the former Junta Nacional dos Resinosos and which we felt deserved a brief review, precisely 50 years after its publication (Lourenço, 2016).

7Almost eighteen years after this publication, considering the weather conditions favorable to the occurrence of fires, Fernando REBELO (1980) started a series of scientific works that have been published and which culminates in the most recent technical reports on the tragic fires of June 2017 (CTI, 2017, and VIEGAS et al., 2017) which, as they developed in the center of Portugal, became known for the fire that caused the most victims, the sadly notorious Pedrógão Grande, with 62 dead. A new report is currently being prepared by the Independent Technical Commission (CTI) on the major forest fires of 15 October.

8These two tragic dates do not even coincide with the normal critical period of forest fires, which is normally between 1 July and 30 September (Sofia FERNANDES, 2015), although, as the Author rightly mentioned, large fires can also occur outside this critical period, whenever the weather conditions are favorable.

9Among the diverse works on the topic of forest fires, we mention some of those that show their geographic distribution in Portugal and the way in which this has evolved over the years. By way of example, we would mention the work of Luciano LOURENÇO et al. (2012), as it touches on the treatment of this information on a countrywide basis, and also that of Sandra Oliveira et al. (2014), as it makes a comparative analysis of Portugal with the other southern European countries.

10Besides these works of scientific investigation, numerous other studies were made, especially on a more local level and more dedicated to the analysis of specific fires, like the first study cases relating to the fires of Mira (Viegas et al., 1987) and of Arganil (Viegas et al., 1988), which was followed by a number of others, such as those by Lourenço et al. (1994), Ferreira-Leite et al. (2014), and so many others dedicated to more specific aspects, before we get to those produced more recently by the Independent Technical Commission (CTI, 2017) and by Viegas et al. (2017).

11However, as they have evolved very differently from what we have seen in other southern European countries, a comparative analysis of the fires in these countries is presented, in order to understand why the problem is more severe in Portugal.

12Then, a series of maps illustrates certain aspects that, indirectly, help us to better understand the distribution of ignition points and burned areas.

13Lastly, we refer to the years that were most critical in terms of forest fires, 2003 and 2005 and, more recently, not only 2016, in which an area of over 150 000 ha was burned, or rather, six times more than what the National Defense System against Forest Fires established as the goal for 2010 (APIF, 2005, p. 69), and also and above all the year 2017, which surpassed all the previous records for the area burned and number of victims.

Methodology

14Taking into account that this work is essentially a summary, the methodology followed is based on an examination of some of the vast bibliography on the topic and on the analysis of diverse statistical data relating to the period under study and, whenever considered convenient, this is represented graphically and cartographically to help visualize the evolution over time and the geographic distribution of the phenomena in question. In addition, the bibliographic sources in which some of these matters were approached in more detail are given, so that people interested in them can find more information.

15With regard to the proposed typification of the diverse generations of fires in Portugal, perhaps the most innovative aspect of this work, we chose to adapt the methodology proposed by Antoni Rifà and Marc Castellnou (2007) for Catalonia, which looked at four generations of forest fires, depending on the behavior of the fire: the first refers to the fires of the years 1950-60; the second relates to the fires of the years 1970-80; the third includes the fires of the 90s and the start of the new millennium up to 2002; the fourth and last, starts in 2003.

16However, some years later, considering the more recent evolution of the landscape and socioeconomic changes, the behavior of the fires needed to be adapted to this evolution, with the addition of a further generation, the fifth (Pau Costa, Marc Castellnou et al., 2011). However, six years later, this update was already insufficient and the model needed to be fine-tuned, reformulating the classification, adding yet another generation of fires, the sixth (CASTELLNOU, 2017).

17From our point of view, we think that the classification with four generations, as was defined initially, is sufficient for classifying the behavior of fires in Portugal, given the respective degree of gravity, which, in a way and in our view, even corresponds with the number of operational situations defined in Spain in the Directriz Básica de Planificación de Protección Civil de Emergencia por Incendios Forestales (BOE, 2013), classified into four different levels, which arise from the characteristics of the respective fires and which, in simplified form, refer to fires that:

  1. Situation 0 - “[…] can be controlled with the means and resources of the local plan itself or that of the Autonomous Community […]”, which corresponds to the situation that we identify as that of the first generation of fires;

  2. Situation 1 - “[…] can be controlled with the means and resources of the local plan itself or that of the Autonomous Community, or whose termination may need […] to incorporate extraordinary means,” which happened in the second generation of fires;

  3. Situation 2 - “[…] require the immediate adoption of protection and aid measures; and it may be necessary for […]extraordinary means to be incorporated […]”, as happened in the 3rd generation of fires;

  4. Situation 3 - reflects a situation of calamity “Situation of emergency corresponding to and following the declaration of emergency of national interest by the Home Secretary […]”, as occurred in 2017.

18So, if we consider that the burned area in each large forest fire reflects the main criteria of the regime of fires, using Castellnou’s classifications mentioned above, such as: intensity, severity, area, frequency, recurrence and seasonality, and if for the Portuguese case we admit multiples of 10 000 hectares as the threshold of transition for the different generations, we can simplify and reduce the number proposed in Castellnou’s last classification from 6 classes to only four.

19In this way, we can easily establish these four classes, which not only have some temporal similarities with the periods proposed above, but also even coincide with the most recent transition threshold years, 2003 and 2017.

20Besides this quantitative criterion, there are naturally others that uphold this division into four generations, namely the number of occurrences and geographic distribution of the large fires, and which will be mentioned in more detail in the characterization of the respective generations.

1 - Results and Discussion

1.1 - Forest Fires in Southern European Countries

21Although the phenomenon of forest fires in the Mediterranean regions is well known (CAMIA, 2009; OLIVEIRA et al., 2014), the analysis is not always made in comparative terms between southern European countries, which deserves to be analyzed.

22In fact, as Portugal is the smallest of five southern European countries (table I), it is therefore surprising that this state recorded the largest average number of occurrences of forest fires (table  II), with a similar evolution, over the years, to that witnessed in Spain and Greece, but clearly different from that of France and Italy (fig. 1).

23While this in itself is noteworthy, what can we say then of the evolution of the area burned (table  III), considering that the behavior is contrary to what was recorded in the four other countries (fig. 2)?

Table I - Comparative surface of southern European countries

Table I - Comparative surface of southern European countries

Source: PORDATA, based on data from Eurostat and National Statistical Institutes.

Table II - Average number of occurrences of forest fires per five-year period, in southern European countries

Table II - Average number of occurrences of forest fires per five-year period, in southern European countries

Source: PORDATA, based on data from Eurostat and National Statistical Institutes.

Table III - Average burned area (ha) per five-year period, in southern European countries

Table III - Average burned area (ha) per five-year period, in southern European countries

Source: PORDATA, based on data from Eurostat and National Statistical Institutes.

Fig. 1 - Evolution of the average number of occurrences of forest fires between 1981 and 2015, in five-year periods, in southern European countries

Fig. 1 - Evolution of the average number of occurrences of forest fires between 1981 and 2015, in five-year periods, in southern European countries

Source: ICNF.

Fig. 2 - Evolution of the average burned area (ha) between 1981 and 2015, in five-year periods, in southern European countries

Fig. 2 - Evolution of the average burned area (ha) between 1981 and 2015, in five-year periods, in southern European countries

Source: ICNF.

24In fact, in these four countries the trend of the average burned area from the first five‑year period to the following periods is highly negative, with an accentuated reduction in Spain and Italy, a decrease being also noticeable in France and even in Greece itself, where although not so expressive, is still also negative.

25On the contrary, in Portugal the trend is clearly positive, resulting from the continuous increase during the first three five-year periods and, above all, from what was recorded at the start of this century, which was particularly expressive because it was twice the value of the previous periods, due to the critical years of 2003, with more than 425 000 hectares burned (the maximum value registered before 2017), and 2005, with around 340 000 hectares (the year, prior to 2017, with the second largest burned area and the year with the most occurrences registered ever, more than 35 000).

26We can find no easy explanation for the trend registered in Portugal, seeing that in five five‑year periods it was different from the other southern European countries. In fact, in Portugal the trend led to an average increase in burned area, while in the other four countries there was a more or less accentuated decrease. And while it then fell to values more in line with those of the first five-year period, the situation is still not comparable to that of the other countries, seeing that in these, with the exception of Greece, the value was around half of that registered in the first five-year period.

27But, even in the case of Greece, where the value of this five-year period was similar to the first, the comparison continues to show an opposing trend, seeing that Greece followed a new and significant drop, while Portugal once again registered another increase, even surpassing the value of the first five‑year period.

28Although Spain also recorded high values, we cannot help thinking that this was much less significant, taking into account not only the area of the two countries, but above all because it represents less than half of the initial value, contrary to what happened in Portugal, where the figures were higher than those of the first five-year period and, more seriously, the following years, 2016 and 2017, confirmed this growth trend.

29In fact, these results clearly show that the policies followed have not been sufficient to invert the general trend, which should lead the governing authorities to think of forest fires less in political terms and look harder and more continuously at the spaces suitable for forestry in order to make them profitable in the midterm. In fact, as political cycles are short term, four years at the most, as opposed to investments in forestry, which should be ongoing in order to become effective in the medium and long term, there is a clear dichotomy with regard to these periods, which has been difficult to overcome, and which could explain the main reason why forest spaces are not attractive for political investment.

2 - Annual Evolution of the Number of Occurrences Compared with the Evolution of the Age, Social and Economic Structures of the Portuguese Population

30The extraordinary increase in the number of forest fires, especially after the 1960s (fig. 3), was due to a variety of causes, resulting from:

  • Local factors, such as previous forestation of common land and of uncultivated mountainous areas, with the corresponding prohibition of the entry of flocks of sheep and goats in these recently forested areas, which severely restricted the breeding of these small ruminants by people living in mountainous regions due to a drastic reduction in their traditional grazing area, and which was an important source of food and revenue for their meagre household budgets (P. FERNANDES et al., 2014);

  • A surge in industrial development especially in the districts of Lisbon and Setúbal, which caused intense internal migration flows towards those districts (CRAVIDÃO, 1989);

  • The start of the colonial war in Africa, in March of 1961, which triggered major migration flows of young men heading overseas to flee the war, namely to France and other countries in Central Europe, and also of adults, to flee the precarious economic conditions of the time, which means that, in the areas they left, there was a reduction in the workforce and demographics. The situation grew worse after the April 1974 revolution, as a result of diverse alterations that were being made in Portuguese society (BENTO-GONÇALVES et al., 2018).

31This whole set of parameters was favorable to the development of fires, meaning that, as from 1974, the burned areas increased considerably each year, to an extent that was previously unknown (fig. 4), whenever weather conditions in the summer period were favorable to the progression of fires (LOURENÇO, 1988a).

Fig. 3 - Annual evolution of the number of occurrences of forest fire in Continental Portugal between 1968 and 2016

Fig. 3 - Annual evolution of the number of occurrences of forest fire in Continental Portugal between 1968 and 2016

Source: ICNF.

Fig. 4 - Annual evolution of the burned area in Continental Portugal between 1968 and 2016

Fig. 4 - Annual evolution of the burned area in Continental Portugal between 1968 and 2016

Source: ICNF.

32In fact, when we analyze the growth of the resident population in Portugal between 1960 and 2011, the year of the last population census (INE, 1960 and 2011), we see that it was positive, as a result of the reduction in the mortality rate and the consequent rise in average life expectancy, which helped to increase the Portuguese population.

33However, this increase was not balanced throughout the whole territory, and so the evolution of the Portuguese population presented a sharp contrast, with a continuous and accentuated reduction of the population in the backcountry, while the municipalities of the coastal areas made major gains (fig. 5). On the other hand, emigration and the rural exodus caused by a lack of resources and future prospects have always characterized Portuguese demography and had greater impact in the interior regions, and contributed decisively towards the loss of population and ageing demographic of these territories (NUNES et al., 2016 and 2018). On the other hand, there were also migrations inside these inland territories, from the more rural villages to the towns and cities, which left the rural areas less populated.

34In fact, the alterations mentioned above resulted not only in the said accentuated rarefaction of the resident population in the forested areas of the backcountry (fig. 5)–a trend that still remains, with important consequences for traditional economy, based principally on the agricultural-forestry-pastoral complementarity–, but also a profound alteration in the structure of the resident population in rural communities, which was felt on various levels, namely in terms of age (fig. 6), leading both to a substantial increase in the older population–whose advanced age makes many of them absentee forest owners, due to a lack of strength and ability to work–, and an accentuated decline of the younger population, which then leads to a shortage of workforce available to drive forest populations.

35In this way, a comparative analysis of the age pyramids (fig. 6) shows that, in 1960, the structure at that time was typical of a young population, with a high birth rate and a relatively low average life expectancy. However, in 2011, the Portuguese population had clearly aged, with a narrowing at the base, which means fewer people in the younger classes, and enlargement at the top, corresponding to an increase in the numbers of the older age groups.

36So, as from the mid-80s, when Portugal joined the European Union, there was a surge in economic development that was also reflected in the age pyramid, seeing that Portugal was no longer a country based on rural economy, having modernized itself. The Portuguese population took on a more urban behavior and women entered the labor market in strength, one consequence being an accentuated drop in births, which led to the profound narrowing of the base of the pyramid. In contrast, the top of the pyramid broadened very significantly, reflecting a reduction in mortality and the consequent increase in life expectancy, and so the pyramid for 2011 is already typical of an aged country and, therefore, less able to intervene in traditional forestry management.

Fig. 5 – Population change in the municipalities of Portugal (1960-2011)

Fig. 5 – Population change in the municipalities of Portugal (1960-2011)

Date source: INE, DGT and CAOP, 2016 version, prepared by Sofia BERNARDINO.

Fig. 6 - Comparative analysis of the age structure of the Portuguese population in 1960 and 2011

Fig. 6 - Comparative analysis of the age structure of the Portuguese population in 1960 and 2011

Source: BANDEIRA et al., 2014, p. 36-37.

37On the other hand, these transformations are also well expressed in terms of sectors of activity, with the primary sector workforce decreasing sharply with workers initially moving into the secondary sector and then into the tertiary sector (fig. 7). So there has been an extremely significant reduction in the population working in the rural community, which, naturally has much fewer people working in forestry (NUNES et al., 2018).

Fig. 7 - Variation of the sectors of activity of the Portuguese population between 1960 and 2011

Fig. 7 - Variation of the sectors of activity of the Portuguese population between 1960 and 2011

Source: PORDATA, based on data of the INE - National Statistical Institute of Portugal.

38Lastly, there were other transformations on a socioeconomic level, which, indirectly, also contributed towards the increase of fuel in forests, namely the following:

  • Firewood and coal are less and less used as fuel, being replaced by gas and electricity;

  • Substantial reduction in the use of animal manure as organic fertilizer, replaced by chemical fertilizers.

39This has led to the accumulation of much combustible material that was previously removed from the woods for these purposes, and which, as it is no longer managed, increases the risk of forest fire.

40In this way, these transformations have gradually left the woods to themselves and, slowly but surely, have come to be propitious for the propagation/progression of forest fires.

41On the other hand, socioeconomic changes have also occurred in the urban population who, in coming to have a better quality of life, can travel to the woods more easily and more often, to occupy their leisure time (weekends, public holidays, holidays,…). With certain urban behaviors inappropriate to the forestry environment, this can constitute a cause of fires (NUNES et al., 2014).

42For these reasons, as we shall see below, the municipalities whose population increases are, in general, recording a greater number of occurrences of forest fires and, in contrast, those with a negative population change record the largest burned areas. The phenomenon arises in part from social transformations and reflects the inappropriate management of forested areas.

3 - Burned Area and Physical Constraints: Meteorology, Relief and Fuel

43If we can establish a certain relationship between the spatial distribution of the occurrences of forest fires (fig. 8) with that of the more densely populated areas (fig. 9), it is also possible to relate the spatial distribution of the burned areas (fig. 10) with topography (fig. 11) and, naturally, with the occupation and use of the land, namely in terms of forest fuels.

Fig. 8 - Spatial distribution of the average number of occurrences of forest fire per 100 km2, by municipalities, between 1981 and 2015

Fig. 8 - Spatial distribution of the average number of occurrences of forest fire per 100 km2, by municipalities, between 1981 and 2015

Source: ICNF. Prepared by Sofia Fernandes.

Fig. 9 - Population density by municipality in 2011

Fig. 9 - Population density by municipality in 2011

Source: Adapted from INE, 2011.

Fig. 10 - Distribution of the average percentage of municipal surface area burned by forest fires between 1981 and 2015.

Fig. 10 - Distribution of the average percentage of municipal surface area burned by forest fires between 1981 and 2015.

Source: ICNF. Prepared by Sofia FERNANDES.

Fig. 11 - Hypsometric map of Continental Portugal

Fig. 11 - Hypsometric map of Continental Portugal

Source: Adapted from IGP [en ligne]

44On the other hand, the temporal distribution of the burned area over the years is related with the types of weather and the weather conditions experienced in the summer season of these different years. Therefore, after 1974, or rather, for more than forty years, only in 11 of these years was the total burned area on record less than 50 000 ha, this being in 1976, 1980, 1982, 1983, 1993, 2015 and, above all, in 1977, 1988, 1997, 2008 and 2014, which recorded the lowest value in the respective decade. This is explained, firstly, by unfavorable weather for the progression of fires with cool and wet summers, at times even with some rain.

4 - Evolution and Spatial Distribution of Major Forest Fires

45The concept of large forest fire has changed over time (FERREIRA-LEITE, 2016). In fact, in the 1970s, a decade when the maximum value of the area burned in a single fire was less than 10 000 ha, large forest fires were considered to be all those whose burned area was equal to or greater than 10 hectares. Later, only large fires whose area was equal to or greater than 100 hectares were considered, and this was also changed to 500 ha when fires with one hundred or more hectares were very abundant, as happened in the years 2003 and 2005.

46On the other hand, while in the 1970s there were no fires of an area superior greater than 10 000 ha, when, in the following decade, in 1986, the first fire with an area greater than this appeared in the municipalities of Vila de Rei and Ferreira do Zêzere, this was considered a truly exceptional situation (LOURENÇO, 1988b).

47Besides this, also for the first time, various large fires were recorded south of the river Zêzere, and so their geographic distribution also changed, extending to the south, for which reasons the year 1986 formed the transition from the fires that we can call 1st generation to what followed them in the 2nd generation.

48However, over time, we became accustomed to the situation and fires with areas of over ten thousand hectares came to be relatively frequent (FERREIRA-LEITE et al., 2014), as happened especially in 2003, when there were nine fires of this size, meaning that this year was the most serious in terms of burned area (fig. 4). Besides this, for the first time in 2003, even bigger fires were recorded, with an area of over twenty thousand hectares, or rather, we can consider this the start of a third generation.

49In turn, the year 2017 saw, according to provisional values available (ICNF, 2017), three fires of over 30 000 ha and two close to this value, or rather, five large fires with dimensions never previously registered, which leads us to consider this as the start of a new generation, the fourth and last, which, generically, may be characterized as follows:

4.1 - 1st generation

50Seeing that prior to the April 1974 revolution forest fires were not a problem, as they only very sporadically reached large dimensions (FERREIRA-LEITE et al., 2014), they were not properly what we can call a generation. However, when considered, they may be included in this first generation which, largely, was due to the profound social and economic transformations experienced in Portuguese society after the April 1974 revolution, with repercussions on forests and on forest fires.

51This first generation lasted until the end of 1985, or rather for 12 years, after “April of 74”, and is characterized by few and relatively small occurrences, with the larger fires consuming areas measuring less than 10 thousand hectares. For this reason, large fires were then considered to be all those that covered 10 hectares or more.

52In terms of geographic distribution, with the exception of one or other large fire in the southern compartment of the hills of the Central mountain range and in the Monchique Hills, in the Algarve, all the others were confined to the North of the river Zêzere (fig. 12‑A).

4.2 - 2nd generation

53The second generation of fires started in 1986, the year during which the first fire occurred with a burned surface of more than 10 thousand hectares of (LOURENÇO, 1988b). This generation lasted until 2002, which equates to a period of 17 years, during which the occurrences were more numerous and of greater size than in the previous period. This is why large fires came to be considered only those of an area equal to or greater than 100 ha.

54The fires of greater dimensions burned areas which, in previous generation, had been affected by two large fires. On the other hand, while the largest fires may have had an area of over 10 thousand hectares, they were all under 20 thousand hectares.

55In terms of geographic distribution, although there was a move towards the South, with the exception of the Monchique Hills, in the Algarve, they were practically all confined to the North of the River Tagus (fig. 12-B).

4.3 - 3rd generation

562003 marked the start of a new wave of large fires, with more than 20 000 ha, which continued in the following year, 2004 and, more recently, in 2012 and 2016. The problem was still far from being resolved.

57In this way, the number of occurrences of large fires remained high and their burned area also increased, meaning that, in 2003 and 2005 only those fires with a dimension equal to or greater than 500 ha were considered large fires (DGF, 2003 and DGRF, 2005).

58In fact, large fires increased in size and came to affect areas that, in previous years, were burned by two or more large fires.

59Furthermore, in terms of geographic distribution, large fires extended throughout continental Portugal (Tagus Valley, Alentejo and Algarve), which clearly defines a new generation of fires (fig. 12-C), the third, which lasted 14 years.

60Before 2017, this had been the worst of the three generations and one of the reasons that helps to explain why 2003 had almost tripled the highest value for burned areas of the previous years (fig. 4). This had to do with the spatial distribution of the major forest fires, which was different from usual, or rather, far from the usual regions of the North and Center, where the largest concentration of fire-fighting devices was to be found.

61Besides this unusual distribution there were also causes of a meteorological nature, seeing that in the North and Center the start of the month of August was cooler than usual, unlike the South where the temperatures were very high, especially during the night and above all throughout the Tagus Valley, due to a heat wave that ran from July 29 to August 14 (PIRES et al., 2003). Furthermore, south of the Tagus, this start to August was also marked by countless dry thunderstorms that led to a vast number of large forest fires, which contributed greatly towards the catastrophic situation experienced in that fateful year (LOURENÇO, 2007).

62The following year, 2004, also started badly, above all because the traumatic memory of the previous year was still very present, due to the large fires in the south, more precisely in the Algarve, when three fires with an area of over 1 000 ha happened on July 25 and, on July 26, a fire started in the Serra do Caldeirão which burned more than 25 000 ha. Fortunately, in the following days the weather conditions changed and the situation was much less serious than had been feared at the end of July.

632005 was also terrible from the point of view of forest fires (LOURENÇO, 2007), as it was the year that registered the largest number of occurrences (fig. 3) and, excluding 2017, was the second-worst year in terms of area burned (fig. 4). Once again the weather conditions were decisive in explaining the reason for so many and such large fires, in as much as much as on August 31, 2005, according to the PDSI drought index, the whole territory was still suffering a severe and extremely intense drought (IM, 2005).

64As would be expected, the dramatic year of 2003 implied the taking of a series of governance measures to prevent a similar situation from being repeated. However, after this, whenever the weather conditions were favorable to propagation, the annual values of the area exceeded 100 000 ha, as happened in 2010, 2012, 2013, 2016 and, especially 2017 (fig. 4), which started a new generation.

Fig. 12 - Evolution of successive generations of fires in Continental Portugal

Fig. 12 - Evolution of successive generations of fires in Continental Portugal

A – 1st generation: to 1985; B – 2nd generation: from 1986 to 2002; 3rd generation: from 2003 to 2016; 4th generation - from 2017. BA - Burnt Area.

Sources: Map A - Oliveira, Pereira and Carreira, 2011; Maps B, C and D - ex-DGF, ex-DGRF and ICNF. Maps prepared by F. Félix.

4.4 - 4th generation

652017 exceeds all expectations and beats all previous records in terms of burned area. The provisional values at the end of October (ICNF, 2017) indicate a burned area of 442 418 ha, the maximum registered since records began, therefore having a higher value than the previous maxima of the fateful years 2003 and 2005. But what is more problematic is the fact that five enormous fires were recorded, three with more than 30 000 ha and another two of around this value, and so, without any doubt, this year marked the start of a new generation of fires, the fourth, which thus corresponds to fires with more than 30 000 ha of burned area (fig. 12-D).

66Even though, with only one year to date, it is premature to point towards other characteristics of this generation. We can add that they cover areas that were previously burned by various large fires, and everything indicates that they appear particularly in the Center Region, traditionally the most affected and, lastly, that their incidence is largely in areas of urban-forest interface, where they cause many victims and enormous material damage, both to residences intended for habitation and industrial installations, indicating the clear inadequacy of fire-fighting resources.

5 - Legislative Measures after 2003 and 2005 and Subsequent Evolution of Fires

67Among the various legislative measures taken was the Resolution of the Council of Ministers no. 178/2003, of November 17, which approved the main guidelines of the structural reform of the forestry sector. This text envisaged the creation of a new organic model for the forestry sector which, among other aspects, was based on the creation of three institutional pillars:

  • The Directorate General for Forest Resources (DGRF), which would have the powers of the national forest authority, namely with regard to forestry planning, forestry police and the prevention of forest fires;

  • The Forest Fire Prevention Agency (APIF), the body responsible for coordinating strategies, the compatibility and orientation of concrete actions to prevent forest fires;

  • The Permanent Forestry Fund, intended to support the forestry sector and activities that are not immediately profitable, and which is financed, namely, by revenue from public and community woods, by revenue from fines applied and by the imposition of a tax, in terms to be defined, on the consumption of oil products. Besides these organisms, the National Reforestation Council was also created, with the aim of coordinating actions to recover the forest areas affected by fire.

68One of these measures that seemed to have an important role in the resolution of the problem of fires was the Forest Fire Prevention Agency, created by Regulatory Decree no. 5/2004, of April 21, but which was quickly and prematurely deactivated by Decree Law no. 69/2006, of March 23, before it had even completed two years. Notwithstanding its short existence and the precarious operating conditions, one of its main achievements was the elaboration, in collaboration with the Higher Institute of Agronomy, of the PNDFCI - National Defense System Against Forest Fires (APIF, 2005).

69Among other measures, the National Defense System Against Forest Fires established a set of affirmative and ambitious goals to be achieved by 2010 (APIF, 2006, p. 16) and that included namely:

  • Reducing the burned area annually to below 0.8% of the forest area, that would equate to 44 thousand hectares per year;

  • Eliminating fires of over 1 000 ha;

  • Reducing the number of fires with an area of over 1 ha.

70When we look at the goal established and the reality experienced in the eleven years following the edition of the PNDFCI and the termination of the APIF, we see that these objectives were only met in 2008, partially met in the previous year, 2007, and again later, in 2014 (table IV), which, as was already mentioned, is mostly attributable to the weather that was unfavorable to the ignition and progression of fires, given that if they had been the result of prevention, structural and circumstantial measures, or the reformulation of the DECIF - Special Forest Fire Fighting Unit, they also would have had an effect in the other years, which was not so.

71Now, according to the data made available in the annual reports disclosed by the ICNF, if in 2007 and 2008, as a result of the inclement weather that did not favor fires, it looked like everything was on the right path for achieving the goals, the values registered in the following years, 2009 and 2010 and, then, in 2012 and 2013, compromised this objective, as these values were even higher than those registered in 2006.

72In turn, in 2011 and 2015, some of the indicators were lower, with values approximating those recorded in 2006, but which, even so, were higher than those defined in the objectives to be achieved for these years. Bucking this general trend, once again due to weather conditions that were very unfavorable to fires, the values registered in 2014 would have reached the stipulated goal, were it not for 3 fires with an area of over 1 000 ha which, together, consumed 5 560 ha of forest. In fact, the objective of eliminating fires of over 1 000 ha seems increasingly difficult to achieve.

Table IV - Goals established in the PNDFCI for 2010 and annual values registered

Table IV - Goals established in the PNDFCI for 2010 and annual values registered

Source: DGRF, Reports; AFN, Reports and ICNF/ANPC/GNR, Annual reports.

73In fact, the last years, 2016 and above all 2017, demonstrated that the measures taken in the interim were manifestly insufficient, seeing that fires of over 1 000 ha not only had not been eliminated, but more than doubled the value of 2006. If the goal of the percentage of burned area in relation to the forest area were applied to 2016, this value would be around 25 000 ha, or rather, six times more area burned than the value stipulated for 2016, which should continue to decrease. Thus, in 2020, the maximum value of burned area would be less than 0.5% of forest area, a desideratum that, prior to 2017, did not seem possible to achieve, taking into account the current evolution.

74Aware of this weakness, even before the fires of 2017, the Government implemented a new “forest reform” which, following a national debate, approved a World Forest Day in the Council of Ministers of March 21, 2017.

75This reform proposal was based on three main areas of intervention:

Forestry management and planning ;

Property ownership ;

Defense of the forest, in terms of prevention and firefighting.

The legislative package thus contemplated a dozen measures, namely:

Creation of a Land Bank;

Setting up a Land Mobilization Fund;

Creation of a Simplified Land Information System;

Creation of a legal regime for the recognition of forest management entities;

Simplification of the process of constitution of FIZ - Forest Intervention Zones;

Alteration of the legal regime of the Regional Forestry Planning Programs, with greater intervention of the municipalities;

Institution of a regime of incentives and exemptions applicable to the forest management entities;

Creation of biomass plants;

Creation of a Forest Markets and Products Commission (CMPF);

Review of the Forest Fire Defense System;

Review of the legal regime of afforestation and reforestation initiatives, in order to halt the expansion of the area of eucalyptus trees and

Creation of the National Fire Control Program.

76In spite of the Government’s good intentions, the amount of burned area in 2017 fully demonstrated to anyone still in any doubt, not only the total inconsistency of many prevention measures taken until then, above all due to not having been accompanied by others that should even have been considered priority, such as fuel management areas around houses, population centers and industrial parks, but also the inadequacy of the firefighting resources at the different risk levels, especially those contemplated for June 17 and October 15, which turned out to be particularly tragic due to the destruction caused.

77Consequently, and like what happened after the forest fires of 2003 and 2005, after the fires of 2017 some of the measures proposed in the forest reform were also accelerated, with the publication of a new legislative package, namely through the following legal diplomas:

DECREE No. 143/XIII. Created a simplified land information system and revoked Law no. 152/2015, of September 14;

DECREE No. 144/XIII. Established the regime applicable to common land and to other means of community production and revoked Law no. 68/93, of September 4;

DECREE No. 145/XIII. Altered the National Defense System Against Forest Fires, making the fifth alteration to Decree Law no. 124/2006, of June 28

DECREE No. 165/XIII. First alteration to Decree Law no. 96/2013, of July 19, which established the legal regime applicable to afforestation and reforestation initiatives.

78While legislative measures are clearly necessary as regulatory instruments, it is more important that they be complied with, both by forest owners and, above all, by the State which, through teaching by example, should show how it is fundamental to correctly manage the forest in order to avoid large fires.

79In fact, while there was a response in legislative terms straight away in 1980 and 1981, when there was the first major reform aimed at the “organization of the defense of mainland Portugal’s forest heritage against the scourge of fires” (Decree Law no. 327/80, of August 26; Law no. 10/81, of July 10; Regulatory Decree no. 55/81 of December 18), intervention in the forest, in spite of this intense production of legislation, has been much less so and, in many years, was almost non-existent.

80Let us hope that this new series of legislation will have quite different consequences from those of the previous packages and may lead to greater intervention in the forest, starting with the properties of the State or those under its administration, as is the case of many stretches of common land, so that, through its example, private owners will be motivated to manage their forest more efficiently, thereby helping to attenuate large fires.

6 - Consequences of Forest Fires

81Among many other consequences of forest fires that are outside the scope of this paper, there are two, however, that stand out in terms of land occupation and which, in turn, determine consequences for how fires behave.

82The first one is that, in spite of the increase in space suitable for forestry, due to the abandonment of agriculture and the consequent transformation of former agricultural fields into forest area, the space effectively occupied by forest has reduced since 1995, given that most of the burned areas are not recovered and are eventually covered with undergrowth and therefore are transformed into uncultivated spaces and not forest.

83Consequently, observations in the field have demonstrated that, in terms of fighting forest fires, the increase in horizontal continuity and, above all, vertical continuity of fuel, due to a lack of management of the woods, has facilitated the propagation of the flames and, therefore, the existence of a greater number of fires in treetops which, being more difficult to fight, helps to increase the number of large forest fires.

84The second consequence involves the alteration of forest species, given that many of the areas burned which, at the end of the 20th century, were occupied by pine forest (Pinus pinaster), have been progressively replaced by plantations of eucalyptus (Eucalyptus globulus). This clear alteration to the forest landscape has led to a progressive reduction of the area of pine forest, by contrast with the continuous increase of the area of eucalyptus forest (fig. 13).

85Now this alteration of forest species has also hindered firefighting, not only because both the flammability and combustibility of eucalyptus leaves are high, but also because they release a large quantity of heat in a short space of time, which hampers direct action, and above all because, by easily generating fires in the tops of the trees, they facilitate their progression. On the other hand, we have frequently observed that this combustion can cause violent upward currents of air, which permit the projection of incandescent material over long distances. These can reach several kilometers, giving rise to new outbreaks of fire, with a multiplier effect in terms of fire fronts, dispersing the performance of the firefighting resources, and also helping to make the burned areas bigger.

86Furthermore, in exceptional circumstances, as happened in 2017, it can even lead to the formation of pyrocumulus and pyrocumulonimbus clouds. These large clouds of smoke formed by fires develop vertically, or rather, rise very high in the atmosphere and, in contact with the colder air of the higher layers of the atmosphere, might cause thunder and lightning, which in turn can create fresh ignitions, to be added to those caused by the projection of the incandescent material, thereby leading to what is called a “firestorm.” Such a phenomenon obviously contributes to the development of fires with truly catastrophic dimensions, seeing that in these circumstances, no matter what firefighting resources may be available, these will always be insufficient to cater to all the needs.

87Lastly, after forest fires, both human intervention and the lack of it, due to a defective maintenance of the infrastructures then created, are harmful for the forest (LOURENÇO, 1990) and for the owners (LOURENÇO, 1991), leading to changes in the forest species and, therefore, to a loss of biodiversity and landscape degradation, along with soil erosion (LOURENÇO, 1989; LOURENÇO and NUNES, 2014).

Fig. 13 - Evolution of the Portuguese forest (in thousands of hectares) in the last fifty years

Fig. 13 - Evolution of the Portuguese forest (in thousands of hectares) in the last fifty years

Source: ICNF-IFN.

Conclusion

88The history of the evolution of Portuguese forests is long (AGUIAR and PINTO, 2007), with increasing intervention from humans as we have evolved, particularly from the second half of the last millennium (PAIVA, s/d), changes that were spurred on from the second half of the last century with the rural exodus, as a reflection of the profound socioeconomic modifications introduced in Portuguese society.

89The progressive abandonment of the forest had the effect of increasing the number of forest fires that are becoming increasingly larger, as time goes by, also contributing towards the abandonment of the forests, thus forming a vicious circle.

90Based on a thorough analysis of the cartography of forest fires registered during the period of time under analysis and of which the analysis carried out for the fires in the Gralheira Mountains (RAINHA et al. 2017) is one example, we think it is possible to establish three generations of forest fires.

91The first of these runs from the 1970s until 1986, when large fires were considered to be those that had an area equal to or greater than 10 hectares. The period is characterized by numerous fires, but with a burned area of below ten thousand hectares, or rather, they were relatively abundant but relatively small.

92This was followed by a second generation, between 1986 and 2002, with fires of larger dimensions, which meant that large fires came to be considered those whose area was over 100 hectares, or rather, ten times more than in the previous period, and in which the area of the largest fire was over ten thousand hectares. In this period there were even more and larger forest fires, covering the same area that, previously, had been burned by two or more fires of the previous generation.

93As from 2003 we entered the third generation of large fires, in which their number reduced, but in which their dimension increased considerably, with large fires covering areas that in the second generation had been burned by two or three fires which corresponds to three, four or more first-generation fires.

94This trend seemed to suggest the existence of fewer, but increasingly larger forest fires, a situation that changed in 2017, with the start of a fourth generation of fires of truly catastrophic dimensions.

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List of illustrations

Title Table I - Comparative surface of southern European countries
Credits Source: PORDATA, based on data from Eurostat and National Statistical Institutes.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-1.jpg
File image/jpeg, 12k
Title Table II - Average number of occurrences of forest fires per five-year period, in southern European countries
Credits Source: PORDATA, based on data from Eurostat and National Statistical Institutes.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-2.jpg
File image/jpeg, 32k
Title Table III - Average burned area (ha) per five-year period, in southern European countries
Credits Source: PORDATA, based on data from Eurostat and National Statistical Institutes.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-3.jpg
File image/jpeg, 32k
Title Fig. 1 - Evolution of the average number of occurrences of forest fires between 1981 and 2015, in five-year periods, in southern European countries
Credits Source: ICNF.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-4.png
File image/png, 35k
Title Fig. 2 - Evolution of the average burned area (ha) between 1981 and 2015, in five-year periods, in southern European countries
Credits Source: ICNF.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-5.png
File image/png, 37k
Title Fig. 3 - Annual evolution of the number of occurrences of forest fire in Continental Portugal between 1968 and 2016
Credits Source: ICNF.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-6.png
File image/png, 81k
Title Fig. 4 - Annual evolution of the burned area in Continental Portugal between 1968 and 2016
Credits Source: ICNF.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-7.png
File image/png, 61k
Title Fig. 5 – Population change in the municipalities of Portugal (1960-2011)
Credits Date source: INE, DGT and CAOP, 2016 version, prepared by Sofia BERNARDINO.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-8.png
File image/png, 703k
Title Fig. 6 - Comparative analysis of the age structure of the Portuguese population in 1960 and 2011
Credits Source: BANDEIRA et al., 2014, p. 36-37.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-9.jpg
File image/jpeg, 168k
Title Fig. 7 - Variation of the sectors of activity of the Portuguese population between 1960 and 2011
Credits Source: PORDATA, based on data of the INE - National Statistical Institute of Portugal.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-10.jpg
File image/jpeg, 72k
Title Fig. 8 - Spatial distribution of the average number of occurrences of forest fire per 100 km2, by municipalities, between 1981 and 2015
Credits Source: ICNF. Prepared by Sofia Fernandes.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-11.jpg
File image/jpeg, 288k
Title Fig. 9 - Population density by municipality in 2011
Credits Source: Adapted from INE, 2011.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-12.jpg
File image/jpeg, 296k
Title Fig. 10 - Distribution of the average percentage of municipal surface area burned by forest fires between 1981 and 2015.
Credits Source: ICNF. Prepared by Sofia FERNANDES.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-13.jpg
File image/jpeg, 292k
Title Fig. 11 - Hypsometric map of Continental Portugal
Credits Source: Adapted from IGP [en ligne]
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-14.png
File image/png, 471k
Title Fig. 12 - Evolution of successive generations of fires in Continental Portugal
Caption A – 1st generation: to 1985; B – 2nd generation: from 1986 to 2002; 3rd generation: from 2003 to 2016; 4th generation - from 2017. BA - Burnt Area.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-15.jpg
File image/jpeg, 2.8M
Title Table IV - Goals established in the PNDFCI for 2010 and annual values registered
Credits Source: DGRF, Reports; AFN, Reports and ICNF/ANPC/GNR, Annual reports.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-16.jpg
File image/jpeg, 60k
Title Fig. 13 - Evolution of the Portuguese forest (in thousands of hectares) in the last fifty years
Credits Source: ICNF-IFN.
URL http://journals.openedition.org/mediterranee/docannexe/image/9958/img-17.png
File image/png, 61k
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References

Electronic reference

Luciano Lourenço, « Forest fires in continental Portugal
Result of profound alterations in society and territorial consequences
 », Méditerranée [Online], 130 | 2018, Online since 08 November 2018, connection on 11 December 2018. URL : http://journals.openedition.org/mediterranee/9958 ; DOI : 10.4000/mediterranee.9958

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About the author

Luciano Lourenço

Department of Geography and Tourism / CEGOT / NICIF, Faculty of Letters of the University of Coimbra, luciano@uc.pt

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