Brazil is set to announce Thursday the establishment of a multibillion-dollar fund designed to pay countries to keep their tropical forests standing. The Tropical Forest Forever Facility would deliver $4 billion per year to as many as 74 countries that maintain their forest cover. The fund requires $25 billion from governments and philanthropies to begin operations. Private investors would contribute the remaining $100 billion. Brazil has committed $1 billion. Countries would receive around $4 …