U-shaped wooden staircases can be made from a variety of woods, including oak, maple, and cherry. The wood can be left natural or stained or painted to match the aesthetic of the home. The treads and risers (the vertical portion of each step) can also be customized in terms of width and height to fit the specific needs of the homeowner.

In addition to the treads and stringers, a U-shaped wooden staircase may also include a handrail and balusters. The handrail is a safety feature that provides support as you ascend or descend the stairs, and the balusters are the vertical elements that support the handrail. These elements can be made from wood or other materials and can be customized to fit the style of the home.

Other features that may be included in a U-shaped wooden staircase include landings, which are flat platforms that provide a resting place between flights of stairs, and newel posts, which are vertical structural elements that support the handrail at the bottom and top of the staircase.

In conclusion, a U-shaped wooden staircase consists of treads, stringers, a handrail, and balusters. It may also include landings and newel posts. This type of staircase is characterized by its bent or curved design and is often used in homes with multiple levels or in spaces where a traditional straight staircase may not fit. It can be customized in a variety of ways, including the type of wood, the width and height of the treads and risers, and the design of the handrail and balusters.