The White Truffle has crossed the Alps

A truffle dog has been finding the valuable White Truffle regularly in a city park in Geneva since 2012. Researchers at the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) have now scientifically studied and documented the fungus. The species could potentially spread northwards with climate change.

In 2012, a truffle dog named Giano made a spectacular discovery: In a city park in Geneva, he unearthed a White Truffle, also known as an Alba Truffle – the first to ever be found north of the Alps. The White Truffle is the most aromatic and valuable truffle; one kilogram can cost up to 10’000 Swiss francs. A research team led by Ulf Büntgen from the University of Cambridge and the WSL now confirms that the underground tubers actually grow regularly at this location.

Between October 2012 and November 2018, Giano excavated a total of 15 truffles under a beech tree in the park. They weighed between five and fifty grams and belong to the species Tuber magnatum Pico according to a DNA analysis. The researchers have now issued a report on the first scientifically verified evidence of the species north of the Alps in the scientific journal "Frontiers in Ecology and the Environment".

Growth possible on the north side of the Alps

"The find proves that the White Truffle can now grow and form fruiting bodies north of the Alps," states co-author Simon Egli of the WSL, who himself owns a truffle dog. He expects additional discoveries on the north side of the Alps in the future. In view of the considerable number of truffle hunters in Switzerland, it is unlikely that the species has spread to the north side of the Alps a long time ago and remained unnoticed until now.

How the valuable tuber got into the Geneva city park, of all places, remains a mystery. Possible explanations could be that the beech planted more than 100 years ago came from one of the White Truffle distribution areas (the Piedmont, Umbria or the Balkans). The fungus may have been in the root system the whole time, but has only recently been able to form fruiting bodies due to the warmer temperatures. Another possibility is that Giano, the dog who often searched for truffles in Italy, could also have transported the fungal spores in his intestinal tract and deposited them in the park. But the mushroom was certainly not seeded by humans, says Egli: "Unlike other truffle species, no one has ever succeeded in doing this with the White Truffle before."

In their natural source regions, the White Truffle yield drops during particularly hot years. As  hot, dry summers are becoming more frequent with climate change, the delicacy is coming under pressure. We know that the distribution of the black or Périgord truffle is shifting northwards, thus compensating for losses in its original source region. Too little is known about the ecology of the White Truffle to assess whether this will occur with this species.