noun
timber rafting; log driving
Technical term for transporting logs by floating them downstream, often bound together in rafts. Compare 筏流し (いかだながし), which specifically refers to rafting.
See also: 筏流し
昔は木材流送が盛んに行われていた。
In the past, timber rafting was actively practiced.
筏流し specifically means transporting logs by raft, while 木材流送 is a broader term for floating timber downstream, which may include loose logs or rafts.
Compound of 木材 (もくざい, 'timber') and 流送 (りゅうそう, 'floating transport'). The exact historical derivation is uncertain, but the term is a straightforward technical coinage.