Tu Bi-Shvat: The New Year for Trees
Tu Bi-Shvat is the new year for trees. Its spiritual qualities express the meaning of “growth” and the inherent sanctity of the Eretz Yisrael that is manifest in its special mitzvot, in the sanctity of its fruits, and in the special link between the land and people of Israel.
The date of Tu Bi-Shvat – the fifteenth of the Hebrew month of Shvat – was fixed in accordance with Beit Hillel’s position in the Mishna (Rosh Hashana 1:1). On this date, a new year begins for fruit of the tree; fruits that begin to develop after Tu Bi-Shvat are considered to be from the new year, whereas those that began to develop before Tu Bi-Shvat belong to the outgoing year. This has several halakhic ramifications:
The mitzvot that apply to tree fruits exclusively in Eretz Yisrael are contingent on when the year begins. The years of a tree’s existence – which increase by one each Tu Bi-Shvat – determines the tree’s age with respect to the mitzvot of orla (the fruits of the first three years, which are forbidden) and neta revai (the fruits of the fourth year, which must be eaten in Jerusalem). There is also a distinction between one year and the next with regard to terumot (gifts to the Kohanim) and ma’asrot (tithes to the Levi’im, the poor, and to be eaten in Jerusalem). The years, which change on Tu Bi-Shvat, determine whether the second tithe will be distributed to the poor or eaten in Jerusalem. Additionally, one may not allocate the produce of one year as the terumot or ma’asrot due from the produce of another year. With regard to bikurim (the first fruits, given to Kohanim), they cannot be brought “from the fruit that developed before Tu Bi-Shvat for the fruit that developed after Tu Bi-Shvat” (Yerushalmi Bikurim 1:6; Mishneh Torah, Hilkhot Bikurim 2:7).
According to some halakhic authorities, the same holds true for the sanctity of the fruits of Shemita (the Sabbatical year, when the land is not cultivated): fruits that developed before Tu Bi-Shvat of the Shemita year belong to the previous year and are not imbued with the sanctity of Sabbatical year fruits.
Joyous customs are observed on this day. Tachanun is not recited on Tu Bi-Shvat or the mincha before it, eulogies for the dead are not delivered, and if it coincides with Shabbat, Av Ha-rachamim and Tzidkatkha Tzedek are not recited. However, unlike Rosh Hashana, there is no prohibition against working on Tu Bi-Shvat.
Over the years, the kabbalists established a special “tikkun” (“rectification”) on Tu Bi-Shvat, in which one eats fruits through which Eretz Yisrael was praised, interspersed with exoteric and esoteric words of Torah praising the fruits and their sanctity. In recent years, the custom of planting trees on Tu Bi-Shvat took root.
In Israeli batei midrash, Tu Bi-Shvat has become a day for studying and clarifying issues related to the sanctity and qualities of Eretz Yisrael, and to the sanctity of the fruits that grow there and are nourished by its holiness.
 There is a dispute amongst Rishonim (medieval halakhic authorities) about the meaning of the term “chanata”, the technical term for the determinant stage of development. Some say it refers to the beginning of the fruit’s emergence, the shedding of the flower petals, or the fruit reaching one-third of its growth.
 See Shnei Luchot Ha-brit (Shlah), Sha’ar Ha-otiyot, Kuf, Shevi’it 57a, cited by Rav Kook in Shabbat Ha-aretz, Hilkhot Shevi’it 4:8. He also notes that “many disagree with him (Radbaz 4:9) and maintain that the fifteenth of Shevat has the status of the new year for trees only with regard to ma’asrot etc. But with regard to the Sabbatical year, the new year is the first of Tishrei.”