Saturday, October 23

The landscape that awaits La Palma after the volcano: a portrait of the future in Teneguía

Just 16 kilometers from the mouths of the new La Palma volcano, on the southern tip of the island, there is a window that allows a glimpse of the near future for the areas now affected by the 2021 eruption: the lesson it has left on earth the half century that has elapsed since the Teneguía volcano released its magma in 1971. A vision that is not hypothetical but rather palpable of solidified lava fields only fifty years old.

Approaching the municipality of Fuencaliente to see the transformation caused by an eruption while the volcano in Cumbre Vieja manages lava forcing the ridge where the eruptive fissures have opened. A 30-minute journey stretches to more than an hour, recalling the blow that the palm trees have been enduring since September 19.

The description of the technicians of the General Directorate of Land Use Planning in the Canary Islands says that, once there, we walk on “a recent volcanic landscape, free of vegetation in most of its surface.” Almost everything is “volcanic badlands” that is, “abiotic elements product of the last volcanic eruptions”. To the eyes of a common walker, black slopes stretch down from the volcanic cones to the sea. The path is made by paths that run between very young lava fields, many times taller than a person. The vision allows to easily distinguish where the lava flows and how the earth remains once it cools: dark, irregular, with rocks based on pyroclasts, peeled …

The petrologist from the Faculty of Geology of the Complutenses University of Madrid María José Huertas tells that “the lava flow, when it cools, becomes a very hard rock.” And also, he adds, “as the cooling is very fast, the upper part of the laundry, which is the one that is being emitted at very high temperatures, comes into contact with the air creating a very rough, very rough crust, with lots of starters and outgoing, very cutting “.

“Outdoor Evolution Laboratory”

A simple walk through the Teneguía wash confirms this process. To the right and left of the marked trails extends that crust bristling with countless volcanic pebbles. That barely created landscape, 50 years in geological terms is less than a blink of an eye, it is what in the Canary Islands is called badlands, made up of type AA lava. The term is Hawaiian and comes to mean “stony” or “rough”, but also “to burn” or “fire”. The other type of lava that has cooled down here was pahoe-hoe, also a Hawaiian term that means “soft” and “easy to walk on.” Without human intervention, “many years, thousands, have to pass for that land to be used,” explains Huertas.

During these days, the place remains almost deserted. Only a couple of scientific groups are observed studying how the eruption affects the ocean. In fact, they take samples at the Echentive beach, which was created with the arrival of the lava from Teneguía to the sea.

This land “is a laboratory of evolution in the open air”, according to the document of conservation norms of this space. “The lava flows and pyroclastic material from the Teneguía covered a large part of the space, destroying the vegetation and burying the soils with plant formations, not being able to recolonize the expelled materials.”

What you can see when you pass through the streams are small green patches of some bushes that are slowly recovering the ground for plants. Among the species that surround and penetrate the rock, botanists describe a unique variety from La Palma that they call cabezón del Teneguía. It only grows on this small portion of the Earth.

Now, only the species that adapt to this extreme environment are settling down and preparing the ground for other more demanding groups to arrive. “Plant and animal communities are constantly changing to consolidate climax communities such as thermophilic forests in the future,” conclude the technicians.

Charo, a palm tree who has been working in the Los Llanos de Aridane displaced persons center, told about whether the islanders feel daily fear when living on a volcano that “what kills us today gives us life tomorrow.” referring to the fertility of the slope where the lava from the San Juan volcano in 1949 fell. The UCM petrologist specifies that “after a certain time, the soils will become very fertile soils and very suitable for But it takes around 100 to 120 years for a tiny edaphic profile to develop and on the order of thousands of years for you to have a well-formed, well-constituted soil. ” “Another thing is that we talk about the soils that are covered by ashes and that, after a while, undergo a different transformation process,” he concludes.

Application of the teachings of the Timanfaya volcano

Thus, bordering these petrified lava rivers that emerged from the interior of Cumbre Vieja in 1971, green rows of creeping vines can be seen at ground level. “The vines are planted directly on the slopes of lapilli without practically altering the orography of the land.” Lapilli is material expelled by the volcano with a diameter between 2 and 64 millimeters. In the Canary Islands they call it picón and it has served to develop an almost own agricultural system.

The vines can be seen growing on the southwest slope of the San Antonio volcano, which exploded in 1677 and whose flows are inscribed in the Teneguía Volcanoes Natural Monument. Its cones are barely 900 meters away. In fact, the 1971 eruption partially overshadowed this one from three centuries ago. The place names of the places where the grapes are now planted leave no doubt as to their origin: Las Machuqueras, Los Quemados, Los Llanos Negros.

The picón crop, apparently, was born on the island of Lanzarote after the six-year eruption of the Timanfaya volcano. After well washing from 1730 to 1736, when the population returned, a kind of agricultural revolution took place by harvesting the crops with a thin layer of lapilli that kept the low humidity, even without irrigation. The first Canarian Malvasia grape vineyards were brought there, the variety that, precisely, now covers the fields of ash and lava cultivated around the eruptions in Teneguía.

The petrologist María José Huertas explains that, if the base material of a soil is of volcanic origin, a very fertile substrate will be generated over time “because the ashes that are deposited on the topography, in the end are a volcanic glass composed of many elements chemicals, for example silica, iron, magnesium … And with alteration, these compounds allow clay to form, then, at the same time, they are also rich in phosphorus and the phosphorus will bind very well, making it easier for there to be many more nutrients. But you have to wait long times. ”

At the moment, lava continues to flow from Cumbre Vieja. Its contact with the sea has created a strip of almost 30 hectares that grows very quickly (tripled in size in 24 hours). The island is gaining ground, but the ground will be as Teneguía and its surroundings teach. Only time will change its nature.

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