The secular celebration of Tu Bishvat that centers on the festive planting of trees began in the Galilee at the turn of the 20th century, and took off within a few years as a quintessential Zionist symbol of regeneration in the Land of Israel. Just as trees would set down roots in the soil, so too would legions of Jews become attached to Palestine. But the momentum behind the holiday - the force that pushed Tu Bishvat from a day marked primarily as a starting point for counting agricultural tithes, as it is described in the Mishna, into a real "New Year of the Trees" rich in symbolism - came from the mystics of 16th-century Safed, who frequented the Biriya forest to meditate on the divine. The Tu Bishvat "seder" that many Jews perform today was intended to be much, much more than the mere enjoyment of fruits native to Israel. Behind the bounty of fruits and nuts stands a highly esoteric ritual of spiritual significance, recorded in a work written in Turkey but based on the kabbalistic teachings of Rabbi Isaac Luria (the "Ari") and his disciples. In the same fields outside Safed where the Friday night service welcoming the Sabbath was authored came a vision of the cosmos that drew heavily on the power and symbolism of nature. In a sense, then, Biriya is where Tu Bishvat was born. It is fitting, too, as the area was home to many of Judaism's early luminaries - evidenced by the fact that the hills in and around the forest are dotted with the graves of rabbinic giants dating back 2,000 years. Buried in the quiet groves are the legendary talmudic rivals Abaya and Rava, as well as the intense Yonatan ben Uziel, whose tomb in the spot known as Amuka has drawn visitors throughout the centuries, and numerous others. Not far off stands the resting place of Honi the Circle Maker, who learned a fabled lesson about trees that completes the ethos of Tu Bishvat. According to the story in the Talmud, Honi (who was so pious that he could demand rainfall in times of drought) chanced upon an old man planting a carob tree. "How long will it take for this tree to bear fruit?" he asked. "Seventy years," came the reply. Incredulous, Honi then asked, "And do you think you will live another 70 years and eat the fruit of this tree?" "Perhaps not," replied the man. "However, when I was born into this world, I found many carob trees planted by my forefathers. Just as they planted trees for me, I am planting trees for my children and grandchildren." Finally, to drive the point home about the importance of such practical deeds, Rabbi Yohanan ben Zakkai added the following dictum: "If you have a sapling in your hand and are told, 'Look, the Messiah is here,' you should first plant the sapling and then go out to welcome the Messiah!"