Oh, Christmas Tree. Oh, Christmas Tree. How lovely are your — lobsters? As the holiday season gets into full swing, some New Englanders are taking their Christmas spirit to new territories — the shellfish industry. Some of the top lobster-fishing ports in New England are taking their traps and using them to create giant Christmas trees. This trap-turned-tree tradition started 12 years ago in Gloucester, Mass., and spread five years later to Rockland, Maine. But this year one town is upstaging both of them. Beals Island, Maine, put up a tree last Thursday that stands 50 feet tall, lights and tall yellow star and all. It may not be quite as nice as the sparkling one at Rockefeller Center, but this tree can do something others can’t — catch dinner.