Sonoma County voters are being asked to approve a countywide tax on cannabis cultivation. Known as Measure A on the March 7th ballot, it faces little opposition because industry experts say most growers would rather pay a tax than a costlier permitting structure. If passed, the measure would impose a tax of between 50 cents and five dollars per square foot for outdoor growers and a little less than two dollars to almost 19 dollars per square foot for indoor cultivators.