The area laid waste by fire in the recent large-scale forest fires in Portugal has been calculated at 122,000 hectares. Around 83% of it lies in the north and centre of the country.

Since 15 September, fires have been raging across central and northern Portugal, claiming at least five lives and leaving 182 people injured. On 20 September the Portuguese government declared a national day of mourning to honour the victims of the fires.

According to figures from Portugal's Institute for Nature Conservation and Forests (ICNF), roughly 122,380 hectares have burned: about 60% of that was forest stands, 29% scrubland and 11% arable land. Portugal is one of the European countries that forest fires in recent years have hit hardest.

Experts say that the recent disaster was caused by strong winds in combination with climate change, which brought higher than usual temperatures at the end of the summer (above 30 °C), along with exceptionally low humidity. Specialists warn that the lack of biological diversity in Portugal's forests and the falling population of the regions concerned are the most significant factors driving extreme forest fires.

“We are heading towards a very worrying situation as regards climate change. Conditions like these will recur more and more often,” said ForEco researcher and coordinator Maria Conceisição Caldeira. “We need a landscape that is specifically adapted to it.”

Former Portuguese Green MEP Francisco Guerreiro is one of the most outspoken politicians calling for greater biological diversity in the country's forests. “Portugal's forests lack biological diversity and responsible long-term management,” Guerreiro said. “We need more forests, and better ones.”

The need for a more diverse forest landscape

According to ICNF figures, 26% of Portugal's forests are eucalyptus, 23% maritime pine (Pinus pinaster), 23% cork oak and 11% holm oak (Quercus ilex). Researchers consider these four tree species “insufficiently diverse” to prevent forest fires from spreading rapidly.

“There is no tree species that would stop a forest fire from spreading,” says Maria Conceição Caldeira. “Nor is there any tree species that determines whether a fire will be more intense or not…” However, since some trees grow for longer than others and can respond differently to fire, a combination of different species across the landscape would help to avoid intense forest fires.

With the devastating forest fires of June 2017 still making their effects felt, forest management has once again come under the spotlight. On 22 September the climate groups Climáximo and Emergência Florestal organised demonstrations across Portugal to protest at the evident inaction on forest fire prevention.

Why is eucalyptus “to blame”?

Many local residents also point to the problems that eucalyptus plantations have caused in Portugal's forests.

Although eucalyptus is native to south-eastern Australia, according to the European Atlas of Forest Tree Species eucalyptus stands cover 1.3 million hectares in Europe. More than 80% of that area is on the Iberian Peninsula. With forest fires becoming ever more frequent, researchers say they understand the public's negative attitude towards the spread of eucalyptus plantations. Eucalyptus trees grow to a height of 70 metres and count as the tallest trees in Europe, and fires in eucalyptus stands tend to be extremely dangerous.

“The link with forest fires follows logically,” says Domingos Xavier Viegas, director of the Forest Fire Research Centre (CEIF). “Eucalyptus increasingly dominates our forests. Eucalyptus trees can produce secondary outbreaks, generating burning particles of wood that can be carried a long way and start new fires.”

Experts point out, however, that the tree is a source of income for people in the north and centre of Portugal. It is widely used for industrial purposes, chiefly for producing pulp, timber and firewood.

“Eucalyptus is a fast-growing species; within 12 years it is already a mature tree,” stresses Maria Conceição Caldeira. “That kind of rapid growth does not apply to most of our native tree species, so eucalyptus brings the Portuguese a significant economic benefit, and as such it also has to be accepted…”