Beyerle knows his stuff, so I stick close, asking him obvious questions like, How come we're not using pigs like they do in Europe? Beyerle tells me that when a truffle matures, it produces a chemical similar to a sex pheromone found in male boar saliva, and this chemical attracts sows. If a female pig finds a truffle, she'll eat it immediately, unless you stop her. And if the sow is full-grown and hungry, this will be a brief and fruitless struggle. So, no pigs today.

At the base of a 20-foot tree, Beyerle points out some white mycelium - white, wispy, goopy stuff that signals the beginning stages of truffle growth. According to Beyerle, the forest was sprayed with mycelium a few years ago in an attempt to accelerate the process. Truffle cultivation is in its infancy, however, and nearly all the world's truffles are still gathered in the wild.

As Beyerle pokes his rake about the ground, he explains that truffles grow attached to tree roots, because as they give the tree minerals and water, the tree feeds back sugars so the mycelium can bear fruit. He then tells me he's found up to 16 truffles in one day. We scratch through the moist soil. Lots of mycelium, but no truffles.

About 100 known species of truffle belong to the Tuber genus. Most valuable to gourmands are the French black (Tuber melanosporum) from the Périgord region, and the Italian white (Tuber magnatum) of the Piedmont district. Oregon has two whites, the Tuber oregonense and Tuber gibbosum, and the Oregon black (Leucangium carthusiana). The black has been called the most complex of any American truffle. It looks like a lump of dark coal, and is said to have aromas of pineapple, papaya, port, mushroom, chocolate, coconut, coffee, butter, pear, and even garlic-teriyaki beef jerky. And, I assume, male pigs as well.