The amazing journey of the 400-year-old Cantabrian holm oak or why we defend centuries-old trees for the wrong reasons

The oldest specimens have been coveted for their tourist interest and used in patriotic speeches. Various voices claim them as symbols of the conservation of the planet, and as a way of imagining continuity in the face of collapse.

To build each galleon, the imposing ships of the Navy in the 17th century, the workers of the shipyards of Colindres (Cantabria) combed the mountains in search of raw materials. They felled oak and chestnut groves and sawed holm oaks to produce charcoal, which they sent to the bullet and cannon factories. In the midst of that destruction, a shoot sprouted, too weak to attract attention, which today, 400 years later, appears as a large tree. It is known as the holm oak of San Roque, a living witness of the last four centuries that has transformed its land, town and climate.

The San Roque holm oak has been recognized with the Tree of the Year 2023 award, a reflection of the respect that the current residents of Colindres profess for it. It is a distinction awarded by popular vote in a Bosques Sin Fronteras contest, which highlights the value of unique trees and their conservation. “When these trees are gone, something is gone that can never be recovered,” laments Susana Domínguez, a forestry engineer and founding president of the NGO. It refers to the flow of climatic and biological information stored by older trees. And also to what these elders represent culturally: “They are witnesses of history. Even if we wanted to replant those trees or 50,000 more, they would never be the same. They are like our great cathedrals.” And every day their planet becomes a more hostile environment for them.

In the words of historian Jared Farmer, from the University of Pennsylvania (USA), the trees are “the quintessential locals. Plants cannot move, they accept what comes to them and their experience of time is different”, he reflects. Perhaps that is why many cultures venerate a tree, from Yggdrasil in Norse mythology to the Bodhi tree of Buddhist tradition. In her recent book, Elderflora: A Modern History of Ancient Trees, Farmer explores that fascination, and what she has discovered is not entirely up to her.

On the one hand, the historical records of the oldest trees are tinged with “male ego”: explorers, scientists, and naturalists—almost always men—competed with saws or tape measures for the largest specimen or the thickest trunk, the one with more growth rings. And the exaltation of the trees that we did not cut down has caused, for the historian, a worrying ethnonationalist drift. “Each country looks for the oldest organism in its territory as a way of expressing a nationalism of blood and land through its natural heritage. Ancient trees have been part of aggressive far-right discourses,” he warns.

It's no coincidence that the largest living tree—a redwood in California that was already a hundred years old when the Roman Empire fell—bears the name of a Civil War soldier, General Sherman, famous for his scorched-earth policy against the Confederates. . When a utopian socialist community occupied what is now Sequoia National Park, the tree was named Karl Marx.

The identity magnetism of the trees also worries Domínguez. As organizer of the Tree of the Year contest, in each edition she has to deal with participants who only seek recognition of a singular tree as a tourist attraction: "If this happens, in the end the tree will import three radishes."

Faced with the nationalist or macho discourse that exhibits the largest or oldest tree as a trophy, there is a movement that proposes to recognize the dignity and wisdom of ancient trees, so that we normally reserve the older people of a town, who have seen it all and they have something to teach the new generations.

 “There are trees and species that have survived previous climate changes. They offer a way to imagine continuity, rather than rupture or collapse,” Farmer muses. Nor can we afford to lose them from a pragmatic point of view: old-growth forests lock up tons of carbon in the branches and trunks needed to mitigate the climate crisis. Protecting old trees is much more important than planting new ones. Because even within the forest, the oldest individuals have extraordinary qualities.

“A mature forest with old trees is very different from a mature forest without them,” explains Sergi Munné, professor of biology at the University of Barcelona, ​​who has spent years studying the longest-lived individuals of black pine in the Pyrenees. In as yet unpublished research, his team has found that ancient pine trees, twisted by time, offer shelter to organisms of other species. They had previously discovered that these specimens have an exceptional ability to adapt. This means that they are a source of genetic diversity, something that strengthens the resilience of the forest; while a young monoculture can fall, for example, before a plague or a drought.

Researcher Suzanne Simard, professor of forest ecology at the University of British Columbia (Canada), speaks of "mother tree" to describe unique, large and old individuals that help young plants to develop. Through a network of mycorrhizae, symbiotic associations between fungi and roots, mother trees supply nutrients and beneficial fungi to the saplings.

 In the case of Douglas-fir, a conifer native to North America, Simard has documented how the parent tree is able to specifically share carbon with fir descendants of its lineage. Sequestering carbon from the atmosphere is crucial: it fattens the plant and cools the planet. Paradoxically, the trunks of ancient trees enclose in their rings one of the best records of past climate variation. Although it is possible to use a fine auger to take samples without cutting down the tree, the technique is somewhat invasive and some experts, such as Munné, do not agree with using it on old trees.