One of four Jewish New Year days, the date recognizes the birthday of all trees.
Fruit trees are held up within the Torah because of their ability to sustain life. In the present, it continues to be about environmental stewardship and may include planting trees and “special meals (Seder) which include the seven fruits of the land.”
Sources: https://www.myjewishlearning.com/article/tu-bishvat-ideas-beliefs/, www.multifaithcalendar.org
