In this photo taken on Sunday, Nov. 10, 2019, a white truffle dug from the earth by Carlo Olivero, who has been hunting for prized white truffles in the hills near Alba in the northern Italian region of Piedmont. (AP Photo/Martino Masotto)

In this photo taken on Sunday, Nov. 10, 2019, a white truffle dug from the earth by Carlo Olivero, who has been hunting for prized white truffles in the hills near Alba in the northern Italian region of Piedmont. (AP Photo/Martino Masotto)

ALBA, Italy (AP) — Rising global temperatures are worrying truffle hunters around the Italian town of Alba, where the most prized specimens can fetch twice the price of gold.

This particularly warm October, eight out of 10 white truffles unearthed by Carlo Olivero with his trusty 3-year-old dog Steel were dark, withered and dried out.

“They are clearly signs of the temperatures,” Olivero said, holding one that he kept in his pocket. The rest he consigned to the soil, allowing the spores to spread and hopefully replenish future production.

Alba, located in the northwestern region of Piedmont, has earned the moniker “white truffle capital of the world” for its particularly fragrant variety of truffle, its truffle fair each fall and its annual charity auction, which pushes prices of the tuber magnatum pico up into the stratosphere.

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A truffle weighing 1,005 grams (2 pounds, 3.4 ounces) fetched 120,000 euros ($133,000) — more than twice the price of gold — from a Hong Kong buyer at this year’s auction.

The longer-term impact of rising temperatures on the highly prized white truffles is still being studied, but they, like other fungi, grow best in cool, rainy conditions. Climate change has in effect delayed peak production from October into November.

“It has been a few years that we have been worrying about truffle production,” said Antonio Degiacomi, president of Italy’s national center for truffle studies. “We have had over the last three seasons one terrible year, one excellent season and one that is decent.”

To stave off the longer-term climate change impact on the production of the highly prized white truffle, experts have launched initiatives to better preserve the territory where they grow. The goal is to safeguard the symbiosis between the truffle and the host plant by encouraging symbiosis between the truffle hunter and the land owner — whose interests often conflict.

Olivero recalled a maker of the region’s famed Barolo red wine who wanted to cut down two oaks — trees that are perfect hosts for truffles — that were shading his vines.

“I told him, ‘The day you take all the oaks, only you will drink your wine,’” Olivero said. “Because the truffle and the Barolo are two formidable components. It is a system that works on the table, but needs to go together first in nature.”

Unlike the more common black truffle, delicate white truffles cannot so far be cultivated, which makes preservation of their environment critical.

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Incentives include a program paying 24 euros ($26) a year to property owners to maintain host trees they might otherwise remove. Truffle associations also strike agreements with absentee landowners to keep their wooded property cleared in a way that promotes truffle growth.

This year’s charity auction white truffle price — 12,000 euros for 100 grams ($13,200 for 3.5 ounces) — compared with a high price at this year’s fair of about 380 euros per 100 grams ($400 for 3.5 ounces). The fair price can increase to as much as 750 euros ($850) per 100 grams in years of scarce production.

After an unusually hot and long summer, this November’s damp, foggy weather has proved perfect for truffle hunting around Alba.

“In these days, the quality is especially high,” said truffle judge Stefano Cometti. “The low temperatures augment the organic characteristics of the truffle and force it to retain the aroma.”

That included a 730-gram (1 pound, 9.75 ounce) white truffle unearthed by Davide Curzietti on Saturday, the largest of the annual truffle fair to date. Judges certified the provenance of the behemoth tuber, which Curzietti sold immediately to a restaurant in Osaka for 3,800 euros ($4,200).

Even after more than four decades on the truffle hunt, Olivero still gets emotional when Steel stops his energetic sniffing of the damp ground.

Steel’s nose is faultless. Through a carpet of wet autumn leaves and muddy earth, the dog picks up the sweet, distinctive aroma of a white truffle and signals his find by rapidly digging on the surface.

“I call it the magic moment, because it means that there is something under there that we were looking for. We still don’t know the dimensions, how big it will be, but the heartbeat speeds up because in that moment, we know there is something,” Olivero said.

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