KanjiJLPT N1
Fence

stockade, fence, weir, entwine around

Mnemonic

A tree is sawn into flat slabs, each shaped like a volume (of book) standing upright on a shelf. Line enough of these wooden volumes side by side in the dirt and you've built yourself a solid fence around the yard!
Additional thoughts
Picture a bookshelf of wooden planks pulled apart and driven into the ground—each 'volume' becomes a fence post. The tree provides the raw material; the repeating volume shape gives the fence its evenly spaced slats.
Quick recall
Slabs from a tree, shaped like a volume (of book), lined up to form a fence.

Details

The keyword for 柵 is fence. This kanji refers to a barrier made of wooden stakes or poles placed in a row, typically used to enclose an area, mark a boundary, or prevent passage. It evokes the image of a simple wooden fence or stockade constructed by driving posts into the ground side by side. The character is used broadly for railings, barriers, and palisades in both literal and figurative contexts.
On'yomi
さく、さん
Kun'yomi
しがら.む、しがらみ、とりで、やらい

Used in vocab