noun
timber rafting; floating bound logs downstream
Refers to the traditional practice of binding logs together into rafts and sending them down a river, often for transport.
昔は山で切った木を筏流しで運んだ。
In the old days, they transported trees cut in the mountains by timber rafting.
Compound of 筏 (いかだ, 'raft') and 流し (ながし, 'flowing/sending downstream').