Framing may be used for various purposes and might consist of any one or a combination of several materials, such as timber, steel, hollowed out trees,[1] complex wire designs,[2] wooden jigs,[3] or the tree itself, living [4]:178 or dead.[5]:58 It can be used in many project designs to support grafted joints until the grafts are well-established. Some processes might employ framing to hold a shape created by bending or fletching mature trees until the tissues have overcome their resistance to the initial bending and grown enough annual rings to cast the design permanently.[13] Others might use framing to support and shape the growth of young saplings [6][7][34] until they are strong enough to maintain an intended shape without support.[30] Still other approaches might employ frames to guide the roots of aeroponically grown trees into desired shapes.