“The Celtic Tree Calendar is a calendar with thirteen lunar divisions. Most contemporary Pagans use fixed dates for each “month”, rather than following the waxing and waning lunar cycle. If this was done, eventually the calendar would fall out of sync with the Gregorian year, because some calendar years have 12 full moons and others have 13. The modern tree calendar is based on a concept that letters in the ancient Celtic Ogham alphabet corresponded to a tree.
Although you don’t have to follow a Celtic path to celebrate the Celtic tree calendar months, you’ll find that each of the themes in the Celtic tree months ties strongly to Celtic culture and mythology.
The Birch Moon is a time of rebirth and regeneration. As the Solstice passes, it is time to look towards the light once more. When a forested area burns, Birch is the first tree to grow back. The Celtic name for this month is Beth, pronounced beh. Workings done in this month add momentum and a bit of extra “oomph” to new endeavors. The Birch is also associated with magic done for creativity and fertility, as well as healing and protection. Tie a red ribbon around the trunk of a Birch tree to ward off negative energy. Hang Birch twigs over a cradle to protect a newborn from psychic harm. Use Birch bark as magical parchment to keep writings safe.
The Rowan Moon is associated with Brighid, the Celtic goddess of hearth and home. Honored on February 1, at Imbolc, Brighid is a fire goddess who offers protection to mothers and families, as well as watching over the hearthfires. This is a good time of year to perform initiations (or, if you’re not part of a group, do a self-dedication). Known by the Celts as Luis (pronounced loush), the Rowan is associated with astral travel, personal power, and success. A charm carved into a bit of a Rowan twig will protect the wearer from harm. The Norsemen were known to have used Rowan branches as rune staves of protection. In some countries, Rowan is planted in graveyards to prevent the dead from lingering around too long.” – Read more – http://paganwiccan.about.com/od/moonphasemagic/ss/Celtic-Tree-Months.htm