Above 3,000 metres on the Tibetan Plateau and across the Himalaya, the wild caterpillar fungus Ophiocordyceps sinensis ('dong chong xia cao', yartsa gunbu) emerges each late spring, prized by traditional medicine and traded at extraordinary prices that drive a vast seasonal harvest economy for local communities. The same highlands and their forest fringes also yield matsutake for export. Overharvesting and adulteration are real concerns, fueling the shift toward cultivated Cordyceps militaris.
Caterpillar-fungus harvest is a brief late-spring window as snow recedes.