Brazil clamped down on the logging of mahogany in the Amazon Rainforest last week, putting in place new rules that require loggers to present plans showing how harvesting will be done sustainably. Brazil produces about half of the world’s supply of mahogany, a highly prized — and highly endangered — wood sought for the making of furniture and instruments. The move by the Brazilian government came less than a week after the U.S. Department of Agriculture rejected nine shipments of Brazilian mahogany on suspicion that the wood was logged illegally. The shipments had been held for more than a year as U.S. officials waited for Brazil to turn over documentation verifying their legality.