When Regula Ochsner returned to Madagascar in 1998, two decades after having worked there, she was shaken. Entire forests, which she referred to as the Black Forest, ‘Schwarzwald’ in her native Swiss German, had all but disappeared. While some had been cleared for farming, most – roughly 80% – had been harvested for firewood. It was either lush green forests or an empty stomach. Both, it seemed, were impossible.