Although Tibetans are known for sky burial, they bury their young in trees. Tree burial is popular with Tibetans in Nyingchi and Kangbei, and applied mainly to the dead infants, though children as old as thirteen have been entombed this way. The 'tree coffin' is generally made of cedar board, and wood inlay, though different vessels hang from the trees, baskets, cloth-wrapped bundles and even plastic containers. The body is cleaned with salt water before being placed in the vessel in a fetal position. The family then hangs the 'basket' from a specially pre-selected tree in the dense woods at the junction of two rivers. Females are commonly hung lower on the tree and males at the top. Once the basket holding the body disintegrates, the remains will fall to the forest floor and left there. The Tibetans believe tree burial allows the dead child's spirit to be reborn to heaven, and prevents the another child death or misfortune in the family.