REDLAND, Ore.

THE forest air was cool and the light translucently green, sifted through the Douglas-fir canopy above and refracted by plumes of sword ferns that sprang from the forest floor. There was a muffled galumphing, a blur of golden fur, and then another, as Sasha and Ashleigh, two golden retrievers, bounded by off-leash in a kind of dog nirvana, followed closely by their owners, Kim Hickey and Erik Campen.

Recent graduates of NW Truffle Dogs, a school in Oregon City, Ore., the four were fast becoming adroit hunters of Oregon truffles, native fungi that are among the Pacific Northwest’s most prized delicacies. The dogs and their owners are also pioneers of a sort, foragers at the forefront of a movement that seeks to improve the reputation of Oregon truffles, and their value in the market, by changing the way they are harvested.

As Sasha and Ashleigh raced along, noses to the ground, in these woods, about 20 miles south of Portland, Ms. Hickey watched intently. But something in the dogs’ postures told her they were following the scent of an animal, the footfalls of a squirrel or a chipmunk.

“They’re crittering,” Ms. Hickey said.

Oregon is home to four known culinary truffles: Leucangium carthusianum, the Oregon black truffle; Tuber oregonense, the Oregon winter white; Tuber gibbosum, the Oregon spring white; and Kalapuya brunnea, the relatively rare Oregon brown truffle.