One such plantation we have visited has a mixture of evergreen non-native oaks and deciduous native oaks. The owner feels that mixing the trees up means you create a habitat mosaic which benefits both types of tree and their symbiotic relationship with both truffle and soil micro-organisms. He also has both species because the evergreen oaks need fewer years to start producing truffles than the native ones.
A young truffle oak plantation, somewhere near Preuilly...His truffle hounds, a shaggy white Jack Russell called Pierre, and a wire-haired dachshund called Odile, are adorable.
Some of the trees have orange markers, and he explained that once a tree has produced a truffle, it gets an ID number and records are kept of how many truffles of what weight were produced in which year.
He only grows black truffles, Tuber melanosporum, which are harvested in the winter, and can be bought at fairs like the one at Marigny-Marmande. He says a few people in the area grow the white Italian or estivale (summertime) truffles - someone over near La Roche-Posay and a couple near Loches, but usually it's black truffles in the Touraine.