SUMMIT — Sheriff's patrol Sgt. Mark Yanez surveys the mess the pot farmers left behind: trash, empty propane tanks and gardening supplies. A blue jug of Power Force Multi Insect Killer and a paper sack with crumbly remains of ammonia sulfate are most damaging to the forest, he says. But Sgt. Steve Carney, leader of the three-man team, knows his crew's efforts will only slow the expanding problem on state and federal lands: marijuana-growing operations that deputies say are controlled by Mexican drug cartels. The pot farms present a multitude of problems. Armed men camp nearby to defend the gardens,...