The simplest form of vine support is a stake driven into the ground beside the vine. A stake supports an individual vine, whereas posts, which are usually thicker than stakes, support several vines from suspended wires. Stakes are a very traditional form of vine support, having been used for centuries. Vines trained to stakes are most common in the old world, although the vineyards of California are a significant exception. Since vines are climbing plants, they are unable to support themselves unless specially trained with a short trunk which thickens with age, as for gobelet vines.