Blooming olive trees in Israel
Tu BiSh'vat is first mentioned in the Mishnah, the code of Jewish law that dates back to around 200 C.E. There, in Rosh Hashanah 1:1, the text speaks of four new years, all of which are connected to an ancient cycle of tithes. Each year, the Israelites were expected to bring one-tenth 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.
Like Hanukkah, Tu BiSh'vat is a post-biblical festival, instituted by the Rabbis. However, the holiday has biblical roots. The tithing system upon which it is based dates back to the Torah and its deep concern with trees, harvests, and the natural world, all of which are at the heart of Tu BiSh'vat. Beginning with the Tree of Knowledge of Good and Evil in the Garden of Eden all the way through to Deuteronomy’s injunction against destroying fruit trees in times of war, our biblical text is replete with trees, both literal and metaphorical. Indeed, the Torah itself often is referred to as an eitz chayim (tree of life), based on a passage in the Book of Proverbs.
Although the celebration of Tu BiSh'vat 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 God’s creation in anticipation of the renewal of the natural world. During this festival, Jews recall the sacred obligation to care for God’s world, and the responsibility to share the fruits of God’s earth with all.
Tu BiSh'vat 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 the Tu BiSh'vat seder.
In modern times, Tu BiSh'vat was nourished by the rise of the Zionist movement in the late 19th and early 20th centuries, which re-emphasized the Jewish people’s connections to the land and the natural world. It was the Zionist pioneers who—with strong financial support from Jews throughout the world who donated trees to mark smichot (special occasions)—re-forested the land of Israel, largely under the auspices of the Jewish National Fund (Keren Kayemet l’Yisrael). As a result of this emphasis on tree planting—on Tu Bish'vat and all year long—Israel stands as the only country in the world with an almost constant net growth of trees.