In 1981, Napa Valley became the first area of California to be designated an American Viticultural Area (AVA). It currently contains ~10% of California’s vineyard area and is probably America’s best known wine region.
The reported vineyard area of Napa Valley in 1990, according to USDA NASS, totalled 33,194 ha, of which 84.2% were bearing. Additional vineyard planting reached a peak in the late 1990s, but since 2006 the total vineyard has plateaued at around 46,000 ha.
The path to 46,000 ha has been brought about by quite distinct planting histories for black and white winegrape cultivars. Black cultivars totalled 18,053 ha (81% bearing) in 1990 and increased in every year up until 2006 when a maximum of 35,174 ha (96% bearing) was reported. Since then the black vineyard has plateaued at just under 35,000 ha, with only very small amounts of non-bearing acreage. With Napa vines typically being replaced after 20-30 years, the current low levels of planting will need to enhanced if a decline of the black vineyard area is to be avoided.
White winegrape cultivars totalled 15,141 ha (88% bearing) in 1990 and have been in consistent decline until 2005 when a low of 10,482 ha (97% bearing) was reported. Since then they have reportedly plateaued at close to 11,000 ha, but again with non-sustainable amounts of non-bearing vines.
The overall effect of these differing histories has been for Napa Valley to move from a vineyard which comprised 54% black cultivars in 1990, to one in where in 2006 they comprised 77% ot the total vineyard. Since then the ratio of black to white cultivars has remained more or less unchanged suggesting, perhaps, that winegrowers are content with the current cultivar mix. The current low level of non-bearing vineyard implies that unless additional vines are planted soon a decline in the productive vineyard area is inevitable.