It may be winter in the U.S., but in Israel, spring is just beginning. The annual Jewish holiday Tu BiShvat honors this moment in time. It's "become for many an environmental holiday, a reminder that we need to care for the earth and nature," says Rabbi Hara Person, chief executive of the Central Conference of American Rabbis. The holiday celebrates the annual new year of trees. Think of it "like a Jewish Arbor Day," Person says. You may also see it written as Tu B'Shevat.