Various usages of a tree.
1) Use the structure of a tree to find the relative position of a node with the root and to fully qualify that node.
2) Use the structure of a tree to discover siblings that share the same parent.
3) Use the structure of a tree to iterate over the siblings by walking laterally between them.
3) Use the structure of a tree to recursively travese the tree to repeat same operations.
4) Use the structure of a binary tree to traverse the tree in preorder, inorder and post order traversal.
5) Use the structure of a tree to find the common ancestor of two nodes
6) Use the structure of a tree to find the predecessor of a node in a binary search tree
7) Use the structure of a tree to find the successor of a node in a binary search tree
8) Use the structure of a tree to find if a node exists in the binary search tree
9) Use the structure of a tree to identify a dendrogram among a flat list of data points
10) Use the structure of a tree and schema definition to validate the data
11) Use the stucture of a tree to select the elements from a document
12) Use the structure of a tree to slice it in different ways
13) Use the structure of a tree to nest it as an expression in another
14) Use the structure of a tree to make a clone or copy a sub-tree
15) Use the structure of a tree to visit elements to perform operations without affecting the tree
16) Use the structure of a tree to do breadth first search or depth first search
17) Use the structure of a tree to color nodes as red or black in specific ways for specific tasks.
18) Use the structure of a tree to organize conditions where each element of a collection is evaluated against a tree
19) Use the structure of a tree to cluster and organize large sets of data
20) Use the structure of a tree for efficiently retrieving spatial data
21) Use the structure of a tree for scoping operations via inheritance and composition