It used to be that marijuana came to the Bay Area from the legendary back country of Humboldt County or the desert fields beyond Tijuana. Now the fields are in the Bay Area, and everywhere else in the state. Marijuana is one of the top cash crops in California, NBC Bay Area's Mike Luery reported. Many of the fields are located next to popular trails and in the middle of state parks. A fierce battle is being waged in our own back yard to remove the pot groves. They are hidden in brush so thick that specially trained officers must...