The USA is seeing historic change regarding marijuana: A fundamental shift is in motion between those who seek to keep it illegal, and the overwhelming populist appeal for legal reform. But as new legal markets have begun to emerge, marijuana agriculture is moving into plain view; the country, some are saying, is experiencing a Green Rush.' Grassland offers a view of this world, peeking beneath the towering redwoods of Humboldt County, an epicentre of cannabis cultivation in California.'