The steep terrain of the Douro Valley makes for some of the most difficult grape growing in the world. The slopes are unforgiving, and the natural soil only a few inches thick. To allow vines to survive the rock, pre Cambrian schist, a crumbly slate- like rock, has to be broken up with dynamite and bulldozers.

Both terracing systems follow the contours of the hillsides like monolithic staircases, but where the terrain allows new vineyards are now planted up the slope, across the contours. These newer vineyards, called vinha ao alto, give high planting density but potential erosion inevitably restricts their sighting.

The main mechanised operations in established vineyards include ploughing, spraying and pre pruning. Specialist mini tractors, a little as 70 cm wide, can travel between the vine rows on the newer patamar terraces and up and down the slopes of vinha ao alto. In terrain like this mechanical harvesting will always be totally impossible.