栅 is mainly used in the compound 栅栏 (zhàlan, 'fence/railing'). It can also be read as shān in technical contexts like 光栅 (guāngshān, 'diffraction grating') in physics.
Left tree radical — wood as material. A 栅 is a fence or palisade, built from vertical wooden stakes lashed together. The radical anchors the material aspect, with same-family chars 椅 chair, 板 plank, 桩 post, 杆 pole.
Right 册 — a pictograph of bamboo or wooden slips bound together with a cord through the middle. The image of upright slats tied in a row is exactly a palisade fence, so 册 here serves as a semantic component rather than a phonetic, painting the fence visually.
