America's most renowned bastion of illicit marijuana growing is threatened by cavernous, city-taxed cultivation warehouses soon to be licensed in Oakland. It is alarmed by cities from La Puente to Berkeley to Sacramento that approved taxes on dispensaries or endorsed medical marijuana cultivation, sanctioning a marijuana economy wider and more competitive than ever. Humboldt seeks to save itself by going legit -- the new Humboldt Growers Association is working for county approval to license and tax outdoor pot plantations of up to 40,000 square feet.