From June to August, three rural regions across Spain are transformed into otherworldly landscapes; trees in the heart of the cork forest are sheared of their bark, becoming brick-red sentinels with leafy tops that guard the woods. And this year, for the first time, visitors are able to experience the harvest with them.

A new eco-tour allows travelers to watch the cork harvest and later follow donkeys carrying towering loads to one of the traditional pueblos blancos, towns whose buildings are painted stark white and which dot the countryside in Catalonia, Andalusia and Extremadura.

The tour, From Bark to Bottle, leads participants on an 11-day trip through Spain’s cork trail to discover the lives of the harvesters, the forest’s biodiversity and the cultural and gastronomic heritage of the area — in essence, the cork’s path from tree to wine. Cork is a renewable resource; every year farmers go to a different part of their land to harvest, only returning to the same trees every nine years.

The tour, the brainchild of the United States-based Cork Forest Conservation Alliance and the ecotourism companies Two Birds-One Stone and Namaste Viajes, lets 40 wine-loving tourists a year (10 on each of four tours) experience the cork harvest and its cultural, economic and social nuances.

“We want people to come home from the trip having fallen in love with the people of the cork forest,” said Patrick Spencer, executive director of the alliance.

The first leg of the $3,500 trip explores Extremadura’s harvest in the southwest of Spain. Farmers there, in the heart of the cork forest, remove bark from the same trees used by their great-grandfathers. The intricate process takes only a few cuts before the harvesters peel the bark away like a sharpening pencil.

In the expansive savannas there, visitors spend four days watching the harvest, eating lunch with farmers and trying their hand at slicing jamón, the salty slab of cured pork that Spain is famous for, on a farm where pigs are raised eating cork oak acorns. Nights are spent in either a high-end hotel tucked in to a refurbished medieval building or an agritourismo, a country estate nestled among cork trees.

Days 5 and 6 take travelers farther south to Andalusia, into Los Alcornocales National Park, the largest national park in Spain housing cork forestry. The focus shifts to food, with visits to artisanal cheese, wine and olive oil producers. The evening can be spent attending group dinners while watching burros carry loads of cork bark into town as the sun goes down. Two vans are available to participants, so early-risers have a chance to head back to the hotel, while others can enjoy a late evening out.

The trip ends in Catalonia, in the mossy and forested northeast, with a visit to a 405-acre privately owned cork forest near the region’s rocky coastline, a sensory experience at the Cork Institute, a cork factory excursion, a small-production cava-maker tour, and a chance to eat fish bought that same morning at a fish auction.

Stops include tiny towns the typical tourist doesn’t see, like ninth-century Ronda, the historic trading center with cobblestone roads and ancient churches that is modern bullfighting’s birthplace. Imagine a city divided by a deep canyon, traversed by an arched bridge reminiscent of a Roman aqueduct.

Cork bark is closely intertwined with the lives of the people in these regions.

“When you go to a little village of 600 people, it doesn’t matter whether you’re a cobbler or you sell cheese or you run a laundromat or you pump gas,” Mr. Spencer said. “All of the money that’s coming into your village is coming from cork, so everyone is invested. There’s an intimacy between the people of the cork forest and their trees.”