(WP) - The Hyundai tractor’s talon slammed into the rock again and again, chopping large pieces of schist into smaller one. It resembled a bucktoothed dinosaur attacking its prey. Then the driver rolled back and forth over the debris, using the vehicle’s treads and weight to grind stone into soil. When he found a piece of rock too big to chop, two men followed with jackhammers and dynamite to blast Mother Earth into submission.

This is how vineyards are planted today in northern Portugal’s Douro Valley. Since Roman times, man has chiseled away at the schist and created vineyards terraced row by row up the steep hillsides. These are the vineyards that produce port, the fortified wine named for Porto, the city at the mouth of the Douro River where the wines are aged and shipped around the world. For the past two decades, the region has produced some of the world’s most interesting dry red and white table wines.

The vineyard I saw being created that sweltering June day stretched from 550 to 600 meters in altitude and crested a hill overlooking a bend in the Douro. Manuel Lobo de Vasconcellos pointed down toward the river, where Quinta do Crasto, the winery where he is chief winemaker, sat perched on its own hill. From this perspective, the Crasto hill seemed insignificant, though it was an old Roman outpost and site of some of the region’s best vineyards.

“At this altitude, we see the soils turning from schist to granite, and that’s better for white wines,” Lobo de Vasconcellos explained as we turned this way and that to shade ourselves from the blazing summer sun. The Douro is famous for red wines, but this vineyard was being planted with rabigato, viosinho and verdelho, three white grapes indigenous to Portugal. White wines — crisp yet floral — are the rising stars of the Douro.

Looking over the spectacular scenery, we could see a patchwork of old and new. Traditional terraces, their walls made of schist torn from the hillsides, stretched more or less parallel to the river, while newer vineyards, planted with the use of modern heavy equipment, ran in vertical rows up and down the hillsides. Older terraces, abandoned and never replanted after the phylloxera epidemic of the late 1800s, lined shadier parts of the unpaved road back to the valley.