According to today's Wine Enthusiast posting by Virginie Boone, Sonoma County wine growers have become 99% sustainable. Larger in size then their neighbors in Napa, Sonoma weighs in with over a million acres, only 6% of which are planted to grapes. But the value of that crop has helped most of the region overcome the pressure from housing and commercial development - the same influences that threatens agricultural land in Napa Valley (read James Conaway's book 'Napa at Last Light...' to get a broader perspective). The labor shortage and expense of providing H-2A housing at no cost is seen as a recurring theme of concern, along with the pros and cons of vineyard automation as an alternative to human labor.
In her article, Boone highlights some of the inspiring personalities behind this drive to sustainability. Recommended reading!