Following the forest fires that started on 15 October last year, researcher Joaquim Sande Silva counted over 2,000 eucalyptus plants in an area of around 3,000 sq m, with the use of a drone.

“Whether we like the word or not, there is invasive behaviour,” he said, stressing that eucalyptus trees should be cut back every 10 to 12 years.

“The problem is mainly in abandoned areas, where there is a great number of fruits that lead to the situation we are witnessing,” he said.

The team also found areas with a great density of eucalyptus in the interior of the centre of the country, where there are around 300 plants per square metre.

In 2018, the government enacted a series of wildfire prevention measures after last year’s devastating forest fires killed more than 100 people and injured more than twice as many.

Critics of past forest policies have argued that the predominance of fast-burning eucalyptus trees in many areas made the effects of the fires much worse.