In this study author aims to summarize the information about beliefs, rituals and Christian calendar of the Bulgarians associated with the tree. It also offers a new approach for story telling and distribution of customs and rituals associated with different tree species along the Bulgarian land. In article includes the following parts: the tree as a symbol in the early mnemonic systems; the tree classification, concepts and beliefs of the Bulgarians associated with tree; pilot implementation of digital ontology of customs and rituals associated with the tree; cooperating technology for on-line editing and use of ontology of Bulgarian folklore worldwide; trends and application of ontology in other folklore domains. The web-address of the ontology on the Internet: http://folkxlittera.pbworks.com/TreesInFolklore