CHEMULT, Ore. — The dusty white pickup truck rolled to a stop on the edge of the Oregon woods, where a father-and-son team of mushroom buyers, the Souvannasays, had set up their tent and scale. “Five,” John Souvannasay said before the driver could even open his mouth. With a resigned nod, the man shoved the gear knob into park.

Some commercial hubs obsess over the price of stock shares, or real estate, or in centuries past, tulip bulbs. This dot of a town in south central Oregon, population 135, briefly flowers each fall into a global capital of the wild mushroom trade, with all eyes fixed on a commodity that few Americans have tasted, or perhaps even heard of: the matsutake.

And at $5 a pound for the best-grade raw matsutakes straight from the woods, paid on a recent evening to pickers at buying tents here like the Souvannasays’, the market has just about crashed into the dirt. For the truffle of Asia, as the matsutake has been called — and worshiped, during its great bull market heyday a generation ago — there is far more supply than demand.