“The biggest thing we found was that the truffles were responding to this hot, dry climate,” says Steidinger. He and his colleagues found that a temperature of 3 degrees Celsius was sufficient to prevent the formation of truffle fruiting bodies. As the growing season shortens, so do the truffles. The relationship with the trees is important because the truffles grow directly on the roots of the trees and provide them with moisture and additional nutrients, while the trees share sugar with the truffles.
This year’s weather has been very high in several countries. Southern England had a hot and dry summer, for example, and the UK’s national service, the Met Office, confirmed in September that it was the hottest time on record. To date, 2022 is also the driest year since 1976.
Two truffle hunters in England who spoke to WIRED say they have seen the results. “Truffles have been very poor this season,” says Melissa Waddingham of the Truffle & Mushroom Hunter website. “Most of them are small, ugly – they’re a lot of insects, and, of course, not a lot of truffles.”
Waddingham looks for mushrooms along the coast of southern England, from Dorset to Essex, where the chalky soil provides the salty conditions that truffles love. They usually get golf ball shaped bodies, but this year most are bigger or bigger.
Sasha Dorey, in Dorset, uses her two Lagotto Romagnolo dogs to hunt for truffles in her friend’s orchard. His experience echoes Waddingham’s: “I’ve been working with truffles for 15 years, but I’ve only noticed a difference in how they’re growing this year.”
Steidinger’s research also showed that even among the varieties of Burgundy truffles – which come from North Africa to the UK – some Europeans were at risk due to rising temperatures.
Steidinger says: “What appears to be a single resilient species is actually a picture of a vulnerable population.” In particular, the truffle-producing countries that most culinary enthusiasts think of – Spain, France, and Italy – are at the heart of the truffle community. So even in the old truffle-producing areas, climate change can wreak havoc, rather than focusing on the far edges where you might expect temperature changes to be greatest.
Burgundy truffle research has attracted the attention of experts. “It’s really amazing; we didn’t expect this from this species,” said Paul Thomas, director of the Mycorrhizal Systems company, which grows truffles.
He praises the methods of the researchers and observes how this year’s heat in Europe has already increased the prices of truffles: “The summer truffle, has been selling like € 1,000 per kilo. It is more than what it is in a typical year.”
More and more, truffle trees are being planted in gardens, including in areas with milder summers—Thomas cites places in Wales and Ireland that have produced truffles this year, some for the first time.
But in areas that are affected by high temperatures, cultivated truffles must be provided randomly with food and reliable water to avoid damage due to drought. Doing this long-term in the Mediterranean, for example, is possible, but it is unlikely to be easy or cheap in the coming years. “Aquifers in these regions are decreasing, and irrigation water is also decreasing,” says Thomas.