cedar bark
Refers specifically to the bark of the Japanese cedar (sugi, Cryptomeria japonica), often used in traditional roofing and crafts.
昔の家の屋根は杉皮で葺かれていた。
The roofs of old houses were thatched with cedar bark.
Compound of 杉 (sugi, 'cedar') and 皮 (kawa, 'bark, skin').