מתני' ארבעה ראשי שנים הם באחד בניסן ר"ה למלכים ולרגלים באחד באלול ראש השנה למעשר בהמה ר' אלעזר ור"ש אומרים באחד בתשרי באחד בתשרי ראש השנה לשנים ולשמיטין וליובלות לנטיעה ולירקות באחד בשבט ראש השנה לאילן כדברי בית שמאי בית הלל אומרים בחמשה עשר בו:
Mishnah: There are four "beginnings of the year." The first of Nissan is the beginning of the year for kings and holidays. The first of Elul is the beginning of the year for animal tithes. Rabbi Elazar and Rabbi Shimon say [animal tithes start] on the first of Tishrei. The first of Tishrei is the beginning of the year for years, for the Sabbatical years, the Jubilees, for planting, and for vegetables. The first of Shevat is the beginning of the year for trees, so says Beit Shammai. Beit Hillel says it is the 15th of that [month]
(23) And when ye shall come into the land, and shall have planted all manner of trees for food, then ye shall count the fruit thereof as forbidden; three years shall it be as forbidden unto you; it shall not be eaten. (24) And in the fourth year all the fruit thereof shall be holy, for giving praise unto the LORD. (25) But in the fifth year may ye eat of the fruit thereof, that it may yield unto you more richly the increase thereof: I am the LORD your God.
The Kabbalists carried this relationship of Tu B'shvat and Rosh HaShanah a step further. For them, trees were a symbol of humans, as it says, "for man is like the tree of the field." (Deut. 20:19) In line with their general concern for Tikkun Olam---spiritually repairing the world---the Kabbalists regarded eating a variety of fruits on Tu B'Shvat as a way of improving our spiritual selves. More sepcifically, they believed that eating fruit was a way of expiating the first sin---eating the fruit of the tree of knowledge in the Garen of Eden. Similarly, trees were symblic of THE tree--the Tree of Lfe, which carries divine goodness and blessing into the world. To encourage this flow and to effect Tikkun Olam, the Kabbalists of Sfat (16th century) created a Tu B'shvat seder loosely modeled after the Passover Seder.
- The Jewish Holidays, Rabbi Michael Strassfeld
(19) When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by wielding an axe against them; for thou mayest eat of them, but thou shalt not cut them down; for man is like the tree of the field; should it be besieged of thee?
Many Jews celebrate Tu B’Shvat by donating money to the Jewish National Fund, an agency that plants trees in Israel. It is also popular to commemorate Tu B’Shvatby eating foods that can be found in Israel, such as olives, figs, grapes, honey, carob fruit and pomegranates. Some of these foods are mentioned in Deuteronomy 8:8, which describes Israel as “a land with wheat and barley, vines and fig trees, pomegranates, olive oil and honey.”
Some Jews make a special seder on Tu B’Shvat that is similar to the Passover seder. This tradition began with Jewish mystics but is becoming more prevalent among Jews who are interested in environmental initiatives.
MyJewishLearning.com, Tu B'shvat
(ז) .רבי שמעון אומר, המהלך בדרך ושונה ומפסיק ממשנתו ואומר, מה נאה אילן זה ומה נאה ניר זה, מעלה עליו הכתוב כאלו מתחיב בנפשו.
Rabbi Shimon says: He who is walking on his way while repeating his studies, and interrupts his studies and says, 'How lovely is this tree! And how lovely is this newly plowed field!' is deemed by Scripture to be as if he was guilty [of an offense punishable by the forfeiture] of his life.