Eucalyptus in Portugal: Why Wildfires Turn Dangerous

At first light in the hills of inland Portugal, the scent is gentle, almost medicinal. White eucalyptus trunks catch the light, their leaves tremble in the dry wind, and from the road the landscape appears peaceful. Yet for many residents, this forest tells more than a story of paper, timber or jobs: it also brings back the summers when the sky turned orange. During the 1950s, these trees were presented as a practical answer for exhausted, eroded and sometimes abandoned land. Seventy years later, they sit at the centre of a heated debate. Quite literally.

When eucalyptus appeared to be the answer for poor land

In post-war rural Portugal, some plots were barely producing anything. Rain washed away the soil, hillsides had been overworked, and many villages were already living with limited resources. Rapid planting across large areas therefore seemed sensible: eucalyptus grew quickly, tolerated harsh conditions and could stabilise certain degraded soils. At the time, no one regarded these young trees as a threat. Instead, they represented the promise of greenery and income in regions desperately short of both.

From the 1950s onwards, the growth of the paper industry accelerated this trend. Valued for its fibres, eucalyptus became a profitable tree: on certain land, it could be harvested far sooner than cork oak or traditional pine. Even today, according to national forest inventories, it covers almost one quarter of mainland Portugal’s forest area. This expansion did not always take the form of vast, perfectly laid-out plantations; it often happened in small increments, plot by plot, shaped by family inheritances and financial needs.

The issue, then, is not a tree that suddenly arrived as an absolute invader. Portugal has also experienced agricultural abandonment, extreme fragmentation of land ownership, a decline in pastoralism and increasingly hot summers. However, eucalyptus has characteristics that alter the situation once a fire begins: leaves containing flammable oils, peeling bark, dry leaf litter and the ability to regrow after fire. For a wildfire, it provides ready-made fuel. When the wind picks up, the landscape can change within minutes.

Why eucalyptus trees can turn an ordinary fire into a disaster

The first practical step is to inspect the ground before focusing on the trees. Around homes, minor roads and isolated hamlets, landowners can create cleared strips, remove low branches and increase the spacing between tightly packed trees. It may seem mundane, even thankless, because it has to be repeated regularly. Let us be honest: nobody truly does it every day. Even so, a maintained area around a home can slow the flames and provide vital extra minutes for emergency services and families alike.

A common mistake would be to assume that felling every eucalyptus tree would solve everything. Many small landowners still rely on this resource, while some sites left bare after felling are also exposed to erosion or encroaching scrub. The challenge is less about identifying one sole culprit than reducing the uninterrupted vegetation that enables fire to race from one valley to the next. Mixing tree species, restoring native broadleaf trees and retaining open farmland takes time, public support and coordination that isolated villages do not always have.

The major fires of 2017, including the Pedrógão Grande blaze that killed 66 people, demonstrated how dangerous a dry, fragmented and poorly maintained landscape can become. Portuguese foresters often repeat one phrase:

“A wildfire is never only the story of a spark; it is also the story of the land it travels through.”

In the most exposed areas, several measures can genuinely make a difference:

• Create a landscape mosaic by alternating eucalyptus, cork oaks, chestnut trees, pasture, crops and open spaces. Fire spreads less easily when it encounters breaks, wet areas or less flammable vegetation. This diversity also restores an agricultural purpose to land that had been neglected.
• Maintain the areas around homes for several dozen metres where local regulations require it. This means cutting dry grass, moving woodpiles away, clearing gutters and preventing branches from touching façades or cables. These are straightforward actions, but they become essential when a fire starts.
• Bring small landowners together through forest management associations. In Portugal, plots are often tiny and may be owned by heirs living far from the village. Collective management makes it possible to fund tracks, vegetation clearance, water points and more consistent felling.
• Protect human activity in rural areas. Livestock, orchards and small-scale crops are not merely nostalgic scenery: they naturally limit the amount of dry vegetation. Once land is no longer inhabited or worked, fire often gains ground before summer has even begun.

Portugal’s real eucalyptus challenge: rebuilding a landscape able to withstand fire

The debate over eucalyptus extends far beyond Portugal’s borders. It raises a highly practical question for every Mediterranean country: what is a forest worth if it grows quickly and generates income, yet becomes unmanageable during heatwaves? The tree is neither villainous nor blameless. It has enabled families to earn a living, mills to operate and fragile soils to regain plant cover. But a model designed for the 1950s does not necessarily meet the droughts and extreme winds of the 2020s.

Residents of burnt-out areas describe this with a weariness that satellite maps cannot reveal. After the flames, hillsides look bare, fences melt, animals search for water and roads retain the smell of ash for a long time. Then, a few months later, green shoots emerge again at the base of charred eucalyptus trees. This ability to regenerate is as fascinating as it is worrying. If nothing changes around them, the cycle can begin again: regrow, dry out, burn. The landscape remembers the choices made within it.

Portugal is now testing stricter rules, restrictions on new plantations in certain areas and more diverse reforestation programmes. The outcome will also depend on small decisions: a neighbour clearing a plot, a municipality helping to bring owners together, or a family choosing to plant several species rather than just one. We all know the feeling of facing a problem that seems too vast to influence. Here, however, every maintained clearing, every preserved meadow and every better-planned woodland edge can affect the course of a wildfire.

Key point	Detail	Added value for the reader
Eucalyptus was initially a rural response	Its rapid growth appealed in Portuguese areas with poor, weakened soils before it went on to supply the paper industry.	Understanding that the historical decision met a real need prevents overly simplistic explanations.
Risk comes from a combination of factors	Drought, wind, agricultural abandonment, dense vegetation, fragmented plots and flammable species create explosive conditions.	The reader can see why removing just one tree type is not enough to prevent megafires.
Forest diversity provides a practical route forward	Mosaics combining broadleaf trees, crops, pasture and cleared areas slow the spread of flames.	This approach shows that a productive forest can also become safer and more liveable.