Indonesia's natural resources are among the most bounteous in the world. They are also among the most abused. Desperate for foreign investment and plagued by corruption and weak regulation, Indonesian governments over the years have virtually invited multinational corporations - and, for that matter, their own citizens - to clear-cut the country's incomparable rain forests, foul the air and pollute the water. Now more than 80 percent of the country's 19,700-square-mile reef system, the world's largest, is at risk. Susilo Bambang Yudhoyono, a former general, became Indonesia's first directly elected president last month partly on the promise of a cleaner,...