Yaku-sugi refers to the ancient cedar trees found on Yakushima, a UNESCO World Heritage site in Japan. These trees, some over a thousand years old, are known for their impressive size and unique, twisted shapes. The Yaku-sugi are a symbol of the island's rich biodiversity and are protected to preserve their natural beauty and ecological importance. The Yaku-sugi forests are home to various plant and animal species, making them a vital ecosystem. The trees thrive in the island's humid climate, which contributes to their longevity. Visitors to Yakushima often hike through these forests to experience the majestic beauty of the Yaku-sugi and the surrounding nature.