西日本有数の天然林が残る京都府南丹市美山町の京都大学芦生研究林（芦生原生林）。紅葉に彩られた由良川最上流部をさかのぼり、川の始まる場所を訪ねた。

The Kyoto University Ashio Research Forest (Ashyu Primeval Forest) in Miyama-cho, Nantan City, Kyoto Prefecture is home to one of the best remaining natural forests in western Japan. We walked up the uppermost reaches of the Yura River, which was colored with autumn leaves, and visited the place where the river begins. (November 10, 2023, Nantan City, Kyoto Prefecture)