There are five levels to deciduous woods (or stratum). Tall trees such as oak, maple, hickory, beech, and elm grow in the tree layer (tree stratum), which range in height from 60 to 100 feet. Small trees, such as dogwoods and redbuds, make up the seedling or small tree layer. Bushes such as azaleas and rhododendrons make up the shrub layer. The herb layer, which includes annual wildflowers, ferns, and ground level plants, is followed by the ground layer, which includes mosses, clubmosses, and lichens.