rack
椸 centers on a rack, specifically a wooden frame for hanging clothes or other items.
椸 combines 木 (tree/wood) with 施, which likely contributes the sound. The character denotes a wooden rack, consistent with the wood radical.
The left side is wood 木, and the right side 施 suggests spreading or hanging. Picture a wooden rack where clothes are spread out to dry.
For イ, imagine an easel (イーゼル) made of wood: the first sound イ cues the reading, and the easel is like a rack for displaying things.