Tu B'Shevat (Rosh Hashanah La'Ilanot).

Tu B'Shevat is a Jewish holiday recognizing "The New Year of the Trees." It is celebrated on the fifteenth day of the Hebrew month of Shevat. In Israel, the flowering of the almond tree usually coincides with this holiday, which is celebrated by planting trees and eating dried fruits and nuts.

Why is it important?

Although the celebration of Tu B'Shevat or Tu BiShvat has a long and varied history, the theme most commonly ascribed to the holiday today is the environment. It is considered a festival of nature, full of wonder, joy, and thankfulness for creation in anticipation of the renewal of the natural world. During this festival, Jews recall the sacred obligation to care for the world, and the responsibility to share the fruits of the earth with all.

Tu BiShvat falls at the beginning of spring in Israel, when the winter rains subside and the pink and white blossoms of the almond trees begin to bud. It is for this reason that almonds and other fruits and nuts native to the Land of Israel – barley, dates, figs, grapes, pomegranates, olives, and wheat – are commonly eaten during a Tu BiShvat seder (a special ritual meal for the holiday).

Origins

Tithes

Tu B'Shevat is first mentioned in the Mishnah (Jewish legal code), where the text speaks of four different new years, all of which are connected to an ancient cycle of tithes. Each year, the Israelites were expected to bring one-tenth (a "tithe") of their fruits to the Temple in Jerusalem, where they were offered to God and also helped sustain the priestly class and the poor. Since fruit from one year could not be used to tithe for another, the Rabbis had to determine when a crop year would begin and end. They chose the month of Sh'vat as the cut-off date, for this is when, in Israel, the sap begins to run and the trees start to awaken from their winter slumber, before beginning to bear fruit.

A season for planting

Some scholars hold that this was also a day for planting trees, especially "marriage trees." It was customary for parents who had been blessed with children during the preceding year to plant special seedlings on the 15th of Sh'vat. Cedars were planted for boys, cypress trees for girls. When the children grew up and married, the trees were cut down and used as part of the chuppah. Some Israelis continue this custom today.

source: reformjudaism.com

Tu B'shevat or Tu BiShvat

(the "15th of Sh'vat")

Tu B'Shevat is sometimes also called Chamishah-Asar BiShvat (the "15th of Sh'vat"), because the holiday is observed on the 15th day of the Hebrew month of Sh'vat, roughly corresponding to February in the secular calendar. Every letter in Hebrew has a numerical equivalent. Thus, alef equals one, bet equals two, gimel equals three, and so on. The Hebrew letters tet (nine) and vav (six), used to make up the "Tu" in Tu BiShvat, have a combined numerical value of 15 (chamishah-asar in Hebrew). Tu BiShvat, then, is an abbreviated way of saying Chamishah-Asar BiShvat or "15th of Sh'vat."

The "Birthday of all Trees"

The Torah forbids Jews to eat the fruit of new trees for three years after they are planted. The fourth year's fruit was to be tithed to the Temple.

Tu B'Shevat was counted as the birthday for all trees for tithing purposes: like the beginning of a fiscal year.

It gradually gained religious significance, with a Kabbalistic fruit-eating ceremony (like the Passover seder) being introduced during the 1600s.

Customs

Jews eat plenty of fruit on Tu B'Shevat, particularly the kinds associated with Israel. The Torah praises seven 'fruits' in particular: wheat, barley, grapes, figs, pomegranates, olives and dates.

A short blessing is recited after eating any fruit. A special, longer blessing is recited for the fruits mentioned in the Torah.

Jews also try to eat a new fruit, which can be any seasonal fruit that they have not tasted this year, followed by another blessing. Hassidic Jews may also pray for a perfect etrog, a type of citrus fruit, to use for Sukkot.

Some Jews plant trees on this day, or collect money towards planting trees in Israel.

source: bbc.co.uk