Tu BiShvat (Hebrew: ט״ו בשבט) is the holy day originally celebrating the Mother Goddess, Asherah, who's symbol is the tree, and so this holy day is known as Rosh HaShanah La'Ilanot (Hebrew: ראש השנה לאילנות), literally "New Year of the Trees."
"Give not sleep to thine eyes, nor slumber to thine eyelids. Deliver thyself as a roe from the hand of the hunter, and as a bird from the hand of the fowler. Go to the ant, thou sluggard; consider her ways, and be wise: which having no guide, overseer, or ruler, provideth her meat in the summer, and gathereth her food in the harvest." -Proverbs 6:4-8