Conservation International, a private, nonprofit organization based in Washington, has a goal in luring tourists to study Spanish and regional ecology: It hopes to safeguard the nationally protected forest that encompasses much of northern Guatemala. Eco-Escuela is part of the trend : installing environmentally benign businesses in sensitive areas to reduce reliance on destructive practices. Previously, people sliced chicle-tree bark to draw resin used in chewing gum. Later, they turned to logging. Many felled trees to carve out milpas, or farms, to grow corn and beans. Even more trees have been sacrificed for firewood.