Aerial view of Mount Gibralfaro, where multiple patches of dry pine trees can be seen SUR
How drought and pests are killing trees in Malaga city

How drought and pests are killing trees in Malaga city

Up to 2,700 dead specimens have been counted in recent months in wooded areas such as Gibralfaro, Monte Victoria, El Morlaco, Parcemasa and Los Montes

Ignacio Lillo


Friday, 2 February 2024, 19:02


Nearly 3,000 trees in Malaga city and its surroundings have died due to the ongoing lack of rainfall.

The drought is causing an abundance of pests to wreak havoc on pines and cypresses, with some 2,700 trees dying in areas such as Gibralfaro, Monte Victoria, Morlaco, Parcemasa and Los Montes, according to data from the University of Malaga.

The city hall has already spent around 180 working days removing dead trunks. The council recognised the problem about a year ago, while the same issue has been noted in Extremadura, the Andalusian coast of Huelva and Cadiz and even in some wetlands in Asturias.

The council's theory is that the trees are drying out due to the lack of humidity and the heat, and as a consequence of this weakening, they are are being attacked by pine borers (a type of beetle).

Cause for concern

The problem is so serious it has led mayor Francisco de la Torre to become personally involved in the search for solutions. He proposed asking for the collaboration of the School of Agricultural Engineering and Forestry of the University of Cordoba, which has experts on the problem, to visit affected areas this month. The Faculty of Biology at the University of Malaga is also investigating the causes.

Enrique Salvo, botanist and director of the chair on climate change, is investigating other possible causes, since, in his opinion, dryness is a manifestation of a plague or a drastic change in environmental conditions, which weakens the tree so much that it opens the door to the entry of insects such as borers.

"From seeing them with a high degree of vitality, and then in just three weeks they pass to total death; it is very worrying," he said. His team is doing field work, looking for the beetle to confirm the hypothesis, and inspecting aerial images of the Gibralfaro - the wooded hill behind the city centre on which the castle of the same name stands - as well as studying leaves in the laboratory.

Salvo said one possible explanation is that high temperatures cause the surface of the soil to become too hot. Another hypothesis is that a type of beetle from China, which is already present in North America and the Iberian peninsula, has arrived in Malaga. It carries a worm that penetrates the area where the insect eats and enters the sap circulation which ends up in the roots. At this point, the tree stops absorbing water and nutrients, and dies.

Roots that support the soil

The botanist said the situation is "very worrying", especially on the Gibralfaro, because of the risks to the soil. "It is tremendously steep and these trees are an extraordinary retaining wall," Salvo said. Since the reforestation of the area with pine and eucalyptus trees in 1938, the roots have become a barrier for debris (soil at risk of falling or crumbling) and act as a retaining wall.

Pilot test

The council set up a pilot test five months ago, where a plot was cordoned off on the Gibralfaro mountain, and the trees studied. These trees are being watered once a week to compare the survival rate of trees drying out to trees that are well-hydrated.

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