European wildfires: The eucalyptus factor

Eucalyptus has played a critical role in intensifying and accelerating wildfires in Portugal and Spain through high flammability and rapid monoculture expansion, whereas in France it has a negligible role due to very minimal cultivation.

Eucalyptus leaves and bark contain rich essential oils that make the trees extremely combustible and cause them to burn much hotter and faster than native broadleaf species.The stringy, peeling bark catches fire easily and acts like floating embers, carried by the wind hundreds of meters ahead to spark dangerous secondary fire fronts. Fast-growing eucalyptus roots absorb large amounts of soil water, drying out surrounding landscapes and lowering local humidity, which primes the forest understory for rapid ignition.

Portugal: Covers roughly a quarter of Portuguese forest land, heavily driven by the pulp and paper industry; it acts as a primary contributor to the speed and intensity of severe summer megafires.
Spain: Concentrated heavily in northwestern regions like Galicia, where industrial eucalyptus monocultures have replaced native oak and pine, escalating local wildfire risks.
France: Cultivated only in isolated Mediterranean pockets rather than vast industrial tracts, meaning French wildfire regimes are instead driven by maritime pines, scrublands, and severe heatwaves.

Eucalyptus plays a highly volatile, catalytic role in compounding forest fire risk across southwestern Europe, acting as a primary driver of increased fire intensity, rapid spread, and localized mega-fires. Originally imported from Australia for industrial timber and paper pulp, the widespread proliferation of eucalyptus monocultures has fundamentally restructured the wildfire landscape across the Iberian Peninsula and parts of southern France.

Fire Dynamics and Extreme Flammability

Eucalyptus trees are evolutionarily adapted to thrive on fire, utilizing specific anatomical and chemical traits that make them highly combustible:

Volatile Oils: The leaves and bark are rich in highly flammable essential oils. Under intense heat, these oils vaporize, feeding explosions of flame that burn significantly hotter than native woodlands.
“Spotting” Behavior: The loose, stringy bark peels away and burns intensely. Strong winds easily lift these flaming debris elements, projecting sparks and embers hundreds of meters—or even kilometers—ahead of the main fire front to spawn dangerous new “spot fires”.
Continuous Fuels: Because these industrial plantations grow uniformly dense and are frequently left unmanaged, they form continuous fuel beds that allow flames to race unchecked across vast geographies.

Portugal: The core epicenter

Portugal is the most heavily impacted nation, with eucalyptus covering over 845,000 hectares (roughly 26% of all Portuguese forests and 10pc of the entire country’s landmass). It feeds a powerful pulp and paper sector that represents over 1% of the national GDP and 5pc of exports. However, the human cost has been massive; fully 83pc of the land ravaged by flames between 2011 and 2020 consisted of pine and eucalyptus. Devastating blazes, like the tragic 2017 Pedrógão Grande fires, have directly spotlighted how these massive monocultures turn the landscape into “giant matchsticks” during intense summer droughts.

Spain: The Galician crisis

In Spain, the eucalyptus crisis is centered heavily in the northwest region of Galicia. Driven by historic rural exodus and land abandonment, thousands of villages have emptied. This has left unmaintained, “feral” eucalyptus plantations to expand rapidly. Because the trees aggressively suck water from the ground, they deplete the local water table, leaving the surrounding ecosystem drier and exceptionally vulnerable to hot, climate-driven summer fire seasons.

France: Isolated but growing risk

While France relies far more heavily on native oaks, beach, and maritime pines, eucalyptus has historically been introduced in small, specific microclimates across southern France and Corsica for the paper industry. In these Mediterranean zones, the tree poses a similar localized threat. Increasingly hot, dry European summers have forced French fire managers to strictly monitor exotic species. This prevents them from forming the dangerous fuel continuities seen across Spain and Portugal.

Eucalyptus creates a vicious ecological loop. The trees possess subterranean buds and thick inner bark protecting them from total destruction. When a fire clears out native ecosystems, eucalyptus outpaces them by vigorously resprouting from charred stumps and aggressively spreading wildlings into the cleared, nutrient-rich soil. This suppresses slower-growing native species like cork oaks, chestnuts, and laurels.