Climate change is increasingly threatening Europe’s prized white truffle harvests, hunters and researchers in Italy and Croatia say.

NICCOLÒ LUPONE, GIADA ZAMPANO ALBA, Italy — Guided by the beam of a flashlight, Tino Marolo follows his dog Stella through the darkness of a Piedmont woodland, searching for one of Italy’s most prized culinary treasures hidden beneath the soil.

In the hills around Alba, home to the world’s most famous white truffles, hunters known as “trifolau” traditionally begin their season on Oct. 1. But increasingly, they are confronting a challenge above ground: climate change.

Months of heat and drought have raised concerns about the future of the prized white truffle, a fungus that depends on cool, moist soils and a delicate relationship with tree roots.

“The entire month of October was affected by the lack of rain in July and August and the high temperatures, so it was characterized by poor production and poor truffle shelf life,” said Antonio Degiacomi, president of Italy’s National Centre for Truffle Studies.

According to Degiacomi, dry and compacted soils have also produced smaller truffles this season.

The difficult harvest comes as Alba and the surrounding Langhe hills welcome visitors for the International White Truffle Fair, one of Italy’s best-known food events, which opened on Oct. 10 and runs until Dec. 6.

A changing climate, a changing harvest For Axel Iberti, president of the fair, the season began slowly, with smaller truffles emerging after a hot, dry summer. More recent rains have improved conditions, helping larger specimens appear.

Despite tighter supplies, demand remains strong. Prices at Alba’s truffle market are running about 20% to 30% higher than last year, Iberti said, while hotels and other accommodations have largely sold out during the fair period. The concerns extend beyond this year’s crop.

“This year certainly stands out from a trend we all know has been going on for five or six years now,” Degiacomi said, citing hotter summers and increasingly erratic rainfall patterns. Back in the woods, Marolo says uncertainty has always been part of the hunt.

“You certainly come home empty-handed more often than you do with a truffle,” he said. “It’s really the thrill of saying: I don’t know what I’m going to find.”From Italy to Croatia, the same warning signs Similar concerns are emerging elsewhere in Europe’s truffle-producing regions, suggesting a challenge extending beyond any single forest or region.

Across the Adriatic in Croatia truffle hunters and scientists describe many of the same challenges, from shrinking harvests to declining habitat suitability.

In oak forests outside Zagreb, truffle hunter Petar Alebic says years of drought have made the prized fungi harder to find.

“Each year for the past seven or eight years has been worse than the last,” Alebic said. “Due to the drought, unfortunately, truffles are becoming smaller and scarcer.”

Alebic estimates this year’s harvest is about 30% below normal and increasingly supplements his income with truffle-hunting tours for tourists.

Scientists studying truffles in Croatia report similar findings. Croatia is home to about a dozen truffle species, according to mycologist Armin Mesic of the Rudjer Boskovic Institute. The most prized, the white truffle, can fetch as much as 4,000 euros ($4,500) per kilogram.

“Drought, a lack of rainfall and high temperatures have a significant impact on both the quantity and quality of truffles,” Mesic said. “Quantities are declining, as is the geographical area where white truffles grow,” he added.

Forests are part of the solution Yet experts in Piedmont reject the idea that the white truffle is doomed. “I don’t think we’re facing extinction; we’re facing a challenge,” Degiacomi said.

Researchers are studying ways to help truffle habitats adapt, including improved forest management and experimental irrigation during prolonged droughts.

“We’re trying to do what nature does, and do it artificially,” Degiacomi said. In Alba, the response increasingly centers on restoring and protecting forests.

Iberti has expanded the fair’s focus beyond tourism to include environmental education and conservation efforts.

“The truffle is the sum, but it’s also the vector,” Iberti said. “People come to Alba and the Langhe to discover everything the territory has to offer.”

Working with municipalities, truffle hunters and landowners, communities have begun creating new public truffle grounds and planting trees that could eventually support truffle growth. “The forest is an act of love and faith for the next two or three generations,” Iberti said.

Advocates say reforestation can help lower soil temperatures, retain moisture and reduce erosion, although it can take more than a decade before newly planted trees become suitable hosts for truffles.

Science looks underground Researchers are also investigating the role of soil microorganisms and looking for tree varieties better suited to hotter and drier conditions.

Attempts to cultivate the prized white truffle continue, but reliable commercial production remains elusive. Unlike black truffles, which can be cultivated, white truffles have largely resisted large-scale production.

As autumn progresses, the size of this year’s harvest will become clearer, along with its effect on prices and supplies reaching restaurants and markets.

For now, however, the ancient partnership between hunters, dogs and forests endures. One evening in the woods, Stella eventually stops and begins to dig. The dog has found a truffle.

Whether future generations will continue to enjoy such moments may depend on a mix of science, conservation and adaptation to a warmer climate. Zampano reported from Rome.