The Talmud states that the first of Shevat is the new year for trees, according Beit Shammai; Beit Hillel, however, start the new year on the fifteenth of Shevat (Tu B’Shevat). This date is just a ritual accounting date to start offering new wood for the Temple in Jerusalem. Tu B’Shevat did not really become a holiday until about 500 years ago, when Kabbalists in Safed first reformed the day by developing a Tu B’Shevat seder modeled after the Passover Seder.
The Tu B’Shevat Seder, like Pesach, has four glasses of different kinds of wines, each (white/winter, rose/spring. red/summer and fruit/fall) connected to a season as well as one of the “four worlds” of the Kabbalistic universe.
Like Pesach, at the Tu B’Shevat Seder we eat 15 special foods, especially those from Israel, such as the seven species mentioned in the Torah. The holiday became a celebration of our connection to the land of Israel and her fruits.
The JNF (founded at the Fifth Zionist Congress in Basel in 1901 with Theodor Herzl’s support, was based on a proposal by a German Jewish mathematician, Zvi Schapira) increased this connection by collecting money for planting trees to reforest the land of Israel (over 280,000,000 trees planted so far).
Environmentally aware Jews choose this day as a day to increase our awareness and care for the environment. Doing so has clear roots in the Torah. While some would say that the commandment in Genesis chapter 1, that we are to subdue the world, implies we can do as we please, this commandment is limited by another – bal taschit, not to destroy.
A verse in Deuteronomy tells us even during war, we are not to destroy fruit bearing trees. Rambam extends this prohibition to any form of gratuitous destruction.
Sefer HaChinuch, a 13th century guide for basic Torah education, explains the spiritual goals of taking care of the environment as follows.
“The purpose of this mitzvah (bal tashchit) is to teach us to love that which is good and worthwhile and to cling to it, so that good becomes a part of us and we avoid all that is evil and destructive. This is the way of the righteous and those who improve society, who love peace and rejoice in the good in people and bring them close to Torah.”
Planting trees in Israel is a very good way to lower the negative aspects of climate change and elevate both HaAretz and HaNefesh (land and soul).