木 (the wood radical) marks 橱 as a wooden piece of furniture. It groups with 桌 (table), 椅 (chair), 柜 (cabinet) and 床 (bed) in the household-furniture family - almost everything in a traditional Chinese room shares this radical.
厨 supplies the sound chú directly and adds a faint storage flavour - the kitchen is where you keep things. Together with 木 it depicts a wooden storage cabinet, originally a kitchen cupboard. Now generalised to any wardrobe or display case.
