Natalya, the Ogham is a Celtic form of divination using an alphabet of 25 rune like characters, each corrsponging to a tree sacred to the Celts. If you are interested in learning more about the Ogham, then look up "The Celtic Tree Oracle" by Colin and Liz Murray. It is an oracle set, that includes a deck of Ogham cards, a Spread cloth, and a book on the Ogham runes.
Hope this helps!