Wildfire erosion control: experts urge barriers before replanting

Experts in Madrid, Spain, said on 23 August 2026 that areas damaged by wildfires should be protected from erosion and assessed by specialists before replanting begins. Barriers on vulnerable slopes can stop rain washing ash and soil into watercourses, they said.

Eduardo Tolosana, dean of the Official College of Forestry Engineers, said support for people who have lost homes, businesses or livestock in fires must come first. Environmental restoration should then begin with an assessment of where action is most urgent, based particularly on slope steepness and the heat reached by the fire in the soil.

Barriers to retain ash and soil

On steep slopes that have been severely burned, specialists recommend small barriers built across the gradient, generally using burnt material from the fire. Known as palisades, albarradas or fajinas, the structures retain soil and ash carried by rain before it reaches streams and rivers.

Tolosana said the barriers can limit both soil loss and water pollution. Miguel Aguado Arnáez, an environmental communicator and professor at the European University, warned that ash can form a film in rivers that restricts oxygenation and harms aquatic flora and fauna.

Natural recovery should be monitored

Immediate replanting is not always appropriate, according to the experts. Many Mediterranean species are adapted to fire: holm oaks and Pyrenean oaks can sprout again, while maritime pine cones open in heat to release seeds.

Jorge Aguado of WWF Spain's Forests Programme said natural regeneration should be given time before planting starts. Bringing machinery and workers onto damaged ground too quickly can cause further harm. Intervention may be needed if regeneration fails, or if new vegetation becomes so dense that it increases the danger from another fire.

A soil analysis should precede any work, Aguado Arnáez said. Fast-moving fires often burn shrubs without substantially damaging the soil, whereas flames remaining in one place for a long period can carbonise it and reduce its capacity to support new vegetation.

Green shoots can appear after about a year, with shrubs initially helping to hold the soil through their roots. A dense forest takes an average of 40 to 50 years to recover. Tolosana put the cost of erosion barriers at between 1,500 and 4,000 euros per hectare, thinning dense regrowth at between 500 and 1,500 euros, and reforestation, where necessary, at between 3,000 and 5,000 euros per hectare.

Topics: Fires · Nature & wildlife · Health · Environment · Wildfires

Source: Europa Press / Mallorca.com