PARIS The black truffle, one of the most exclusive and expensive delicacies on the planet, is under threat from climate change.
A mysterious species of underground fungi with reported aphrodisiac and therapeutic properties, the aromatic truffles are also highly fragile and cannot withstand more than three weeks without water.
But prolonged drought in many of their prime growing regions in Europe and predictions about global warming suggest the future is about as black as the truffles themselves, to the despair of the growers.
"The bad harvest years, which used to be the exception, are becoming the norm," Jean-Charles Savignac, President of the Federation Francaise des Trufficulteurs (FFT), told Reuters.
The three main producers -- France, Italy and Spain -- provide about 100 tonnes of the gastronomic luxury per year. In the 19th century it was an estimated 1,000-1,600 tonnes.
In France, this winter's harvest yielded just over 20 tonnes of the high quality black truffle, half what had been expected.
Meteo France forecasts that by the end of the century Toulouse, on the southern fringes of France's truffle growing region, will see temperatures exceed 35 degrees Celsius (95 Fahrenheit) on average between 25 and 55 days a year. Today, it registers such heat on average 4 days a year.
The shortage of supply coupled with rising demand has seen prices soar. A kilo of black truffles can fetch as much as 1,000 euros ($1,548), three times the cost at the end of the 1990s.
But the high prices have not calmed the nerves of truffle producers in France's southern growing fields.
"There are a lot of plantations coming to maturity, but at the moment we cannot say what the future will hold for truffle production," said Jean-Pierre Audivert, President of the Departmental Federation of Perigord Truffle Producers.
While changing weather patterns are reducing harvests in the Mediterranean area, global warming has made regions further north better suited to truffle cultivation.
Farmers have even started to spread the spore of the rare fungus in northern England in a bid to cash in on the popularity of the so-called black diamond.
But the truffle's fragility to frost makes it unlikely that these regions will compensate for falling yields in the south.
With demand exceeding supply, wholesalers are trying to meet some of the shortfall by importing truffles from China.
Similar in appearance to Europe's black truffle, but with little of the flavor, purists have decried the Chinese product, which costs a fraction of the price of the French truffle. The FFT has called on the European Union to ban the imports.
Producers believe the answer to the shortages lies with science and are hooking up with researchers to find ways to adapt to the weather and increase yields.
"The idea is not to suffer, but to understand in order to react," said Jean-Marc Olivier, Director of Research at the French National Institute for Agronomical Research.
For now scientific research is investigating ways in which truffles can be better protected from drought and frost. But any changes will take time, with new plantations taking 10 years before they start producing truffles.
In 2007 alone, 300,000 trees were planted in truffle plantations across France, but only 10 to 15 percent of them will eventually yield the fragile tuber.
"The production zones of the Mediterranean plain are on the frontline and will face further difficulties if we do not adapt," Olivier told a conference of truffle producers.
(Editing by Janet Lawrence)