The Celtic Tree Oracle features the Druidic Ogham, the Celtic system of runic characters from the British Isles and Ireland, that correspond to particular trees and their attributes such as Yew, Heather and Oak. The wonderful artwork is hand drawn in earthy colours, and very peaceful. Buy this deck now at Amazon.com.
The Celtic Tree Oracle deck is based on the Celtic Ogham runes. There are 25 cards in standard playing card size (2.5 x 3.5 inches). They are high quality cards with a wax coating that should last as long as you shuffle with care. The artwork is hand drawn by Vanessa Card. It uses earth tones in a medieval celtic style. I find the art relaxing and it puts me in the correct frame of mind for a reading. The back is green with a gold outline of a celtic solar cross (equal sides like a '+' sign) contained within a circle and gold border.
An issue is that they chose to write the date on only one end of the back so you can tell if the card is reversed or not, which could have an impact on the reading due to the way the cards are read: You lay all 25 face down in 5 rows of 5. The querent then picks 5 of them and writes the card in one of 5 categories (Foundation, Spotlight, Vocalization, Dreams or Etheric Link) based on the order the card was chosen. This process is then done 2 more times resulting in 3 cards in each of the 5 categories with some potentially repeating. The cards are then interpreted based on their interaction within each section. I avoid looking at the back of the cards by placing something, usually a candle, just past the cards to focus on so that I only see the spread through my peripheral vison.
When I recieved the deck (it was a gift), it came with a book explaining the history of the ogham and celtic views of the qualities of trees and, consequently, the oghams asociated with them. The descriptions are quite well written starting first with some form of story that exeplifies the qualities being explained followed by a summation. It also came with a notebook for readings which I though was a nice touch especially if you are starting out.
To get the most from the cards I found it necessary to read the entire story and summation of each one drawn. I also found myself reading about oghams and celtic trees in other sources for further background.
Because of the way that the cards are intended to be used, at first I thought that the deck would only be useful for more involved questions about large issues. They are quite good for this. I was then inspired to use the cards in a more traditional Tarot style spread and see what happens. I was suprised at how effective it was. I tried both the celtic cross spread and the tree of life spread. They seemed fitting. I would only suggest trying other spreads after using the cards in the intended way long enough to become familiar with the meanings.
I'm not sure if being a beginner or an experte is entirely relevant for this deck as the symbology used is so different from traditional tarot. I do think that the skills are the same in terms of interpretation and instinct about what is being implied, so it would probably help if you've done a reading before with another kind of deck.