There are four new years: The first of Nisan is the new year for kings and festivals; The first of Elul is the new year for tithes of animals, though Rabbi Eliezer and Rabbi Shimon say it is the first of Tishrei; The first of Tishrei is the new year for years and Sabbatical and Jubilee years, and for planting and for vegetables; The first of Sh'vat is the new year for trees according to the House of Shammai; the House of Hillel say the fifteenth of Sh'vat. -Mishnah Rosh Hashanah 1:1
"Tu" (the Hebrew abbreviation of 15th) in the month of Shvat was set (Hillel's opinion generally overrules Shammai's) as the beginning of the tithable year for tree fruit: Calculating the tithe on fruit starts again for fruit that sets after that date. The day is not mentioned in the Bible at all, and in the rabbinic literature only in this technical discussion. It seems that only much later, in 16th century Safed, did the kabbalists try to give it a deeper meaning, and invented a custom of having a festive meal of the fruit of the land on Tu BiShvat, while discussing the mystical meanings of the shapes and structures of the fruit. The custom did not spread much (until the late 20th century, when Jewish educators took it up).
Meanwhile, the Jewish National Fund, with the teachers in the schools in the New Yishuv in Palestine in the early 20th century, invented the association between the new year of the trees and the planting of trees in order to green the desertified and swampy land of Israel. Tu BiShvat became a major event in the calendar of the Zionist schools, as the teachers took their students out for the day on festive mass tree-planting excursions. Today these excursions barely exist any more, but the older custom of the seder has become widespread. They are held in schools and youth groups, in synagogues and community centers. They often focus on texts relating to the environment in general. The tables are laden with dried fruit, almost all of which is imported. The only reason to associate dried fruit with Tu BiShvat is that in the Diaspora before refrigeration and air freight, the only Israeli fruits one could obtain were dried – especially carob. It's a little weird that that custom became so ingrained that now we sit in Israel and import dried fruit from Turkey to celebrate the day.
Every year our seminar center in the Galilee, the local county culture department, and the Orthodox community of Moreshet cosponsor a seder. This year we had well over 200 people, from across the religious spectrum. We do a brief seder involving eating the seven species mentioned in Deuteronomy 8:8 (wheat, barley, figs, dates, grapes, pomegranates, olives), and invite a professional entertainer to perform. This year the program was by Golan Azulai, a well known TV and movie actor who, like many in the Israeli entertainment industry, has gone through a sort of re-attachment to his Jewish roots in recent years, and does a show in which he talks and sings about his experiences. He was great, and had us all laughing and singing along with great enthusiasm, as he charmingly avoided both sticky pietism and nasty mockery. And as the county [Orthodox] rabbi, Rabbi Eliahu, pointed out in his remarks, we read in the papers about segregation, and animosity over religious enforcement elsewhere. But here we are, singing, eating, and laughing together – men and women, Orthodox and liberal and secular – and taking it for granted. In my remarks (Rabbi Eliahu and I always share the honors on Tu BiShvat, among other occasions), I suggested that if we could only export the spirit of that evening – the shared culture, the mutual respect, the ability to laugh at ourselves, the rejoicing in the tradition and in the land - to the rest of the country, maybe redemption would come.
Originally published in Ten Minutes of Torah.