What caused Portugal's deadly forest fires?

Heat, dryness and strong winds all contributed to the forest fires that have killed 64 people and injured 157 in Portugal. But criticism is also growing over industrial forestry and lack of enforcement of environmental laws.

Firefighters battle the flames near houses in the village of Pessegueiro, 18 June 2017. Lusa/Paulo Novais

Portugal’s government declared a state of emergency in the central forested region around Pedrogao Grande, and Prime Minister Antonio Costa called this fire “the greatest tragedy” the country has seen in recent years when it comes to forest fires.

But while such blazes are rarely so deadly, forest scientists say they are part of a growing trend.

“Nowadays, even in years with low fire activity, where the area burned is below average, we usually find at least one large fire, more than 5,000 hectares,” says Paulo Fernandes, professor of forestry at the University of Tras-os-Montes e Alto Douro.

“In this particular case it was three different fires that merged, and the burned area is about 50,000 hectares, so it will be the third largest continuous burned area ever in Portugal.”

Weather and land use blamed

In terms of what is driving such a trend, Fernandes cites a mix of economic and environmental factors.

“Weather, or climate if you look on a larger time scale: less rainfall in spring for example, and more extreme conditions in terms of relative humidity and temperature,” he says.

“In terms of land use, there is a trend for people to abandon the more rural areas and, if people abandon agriculture, shrubs and trees will colonise and take over. We did a study last year that shows the main factors that contributes to fire size in Portugal is the continuity of forest and shrubland cover.”

Recent weeks have seen a mix of very hot and dry conditions as well as high winds capable of quickly spreading the fire.

Papermakers import eucalyptus

But there is also criticism of pine and oak forests being replaced by highly combustible eucalyptus trees by the paper and pulp industry.

“For a wildfire there are three important things; you have to take into account the fuel, the weather and the topography, so the shape of the terrain,” says Thomas Smith, a lecturer in geography at King’s College London.

“As far as the fuel is concerned, a shift to a more eucalyptus-dominant forest is certainly going to increase its flammability, because eucalyptus is a kind of oily tree that’s very flammable, and it’s also susceptible to what we call crown fires, where the top of the tree can burn.”

Fires predicted but not prevented

There are also questions as to how well prepared the authorities were.

“Every year we have big fires, and this one is different because it has killed a lot of people, but it’s no surprise at all,” says João Branco, a forestry engineer and president of Portugal’s largest environmental group, Quercus.

“Almost every year, we notify the government and authorities about the danger the Portuguese forest is becoming, because there is no management and the whole landscape system is being replaced by a continuous area of industrial forests of eucalyptus.”

In addition to industrial forestry, Branco says public officials at all levels have been lax when it comes to enforcing laws about clearing away flammable undergrowth.

“The legislation says that on each side of the street, the local government has to clean 10 metres, taking out the combustible material, and also that around the village you have to clean 100 metres, and no one is doing that,” he says, adding that Quercus sought legal action over the issue in 2013.

“Nobody did anything about it, so here we have guilt divided between the central government, the local government and the justice system.”