For 23 years, Curtis Abbott and his family have been growing and selling Christmas trees on their farm in the town of Charlton, Massachusetts. Photos from previous harvests show picture-perfect trees — towering evergreens with sturdy branches dusted with white snow. But this year, Abbott Tree Farm has shared no photographs.Instead, a couple of days before Thanksgiving, the farm posted an unexpected message on Facebook: “Sorry we are closed.” Drought, said Abbott, had forced the farm to shutter its doors this year — only the second time it’s done so in over two decades. “We feel it would be best to keep the farm closed,” he wrote on Nov. 22.Massachusetts has been plagued by drought for months. As of last week, more than 60 percent of the state was suffering severe drought conditions, according to the U.S. Drought Monitor. The dry weather has wreaked havoc on the state’s wildlife, water and vegetation.