File systems are an example of a hierarchical structure that can be represented by a tree data structure. The top level directory is the root, and the directories underneath it are its children

Organisation charts can also be represented by a tree data structure. The CEO is the root, and the employees underneath them are the children.

Routing tables in networks are often represented using tree data structures. Each node in the tree represents a network, and the children of that node represent the subnetworks that can be reached through that network

HTML documents can be parsed into a tree structure called the Document Object Model (DOM). Each element in the HTML document is a node in the tree, and its children are the elements contained within it

Decision trees are used in machine learning and data mining to model decisions and their possible consequences. Each node in the tree represents a decision, and the branches represent the possible outcomes

Syntax trees are used in natural language processing to represent the structure of sentences. Each node in the tree represents a word or phrase, and the children represent its constituents

Binary search trees are used to efficiently search for data in large datasets. Each node in the tree represents a value, and the left and right children represent values that are smaller and larger than the node, respectively

Huffman coding is a compression algorithm that uses a tree data structure to assign variable-length codes to characters based on their frequency in a message

Genealogy charts can be represented by a tree data structure. Each node in the tree represents a person, and the children represent their ancestors and descendants.