12a. Any one of the large arboreous woody plants with crowns forming a forests canopy, the frame of a saddle, or a foot-like device for preserving the shape of a shoe. (4)
52a. A gam of dolphins or whales, a passenger compartment of a Ferris wheel, or a net for catching eels. (3)
2d. Filling in a chocolate, hub of a city or town, midpoint, or a nucleus. (6)
36d. Bottom of the sea, layer of oysters, garden plot for roses, or the bouncy part of a trampoline (3)