Tu Bishvat - A Common Misconception
Sorry - I'm a bit late on this post. Good to know for next year, though.
The first Mishna in Rosh Hashana says that Tu Bishvat is the New Year for trees, according to Beit Hillel. A common misconception is that trees are judged on Tu Bishvat just as people are judged on Rosh Hashana. Actually, trees are judged on Shavuot (says the Gemara in Rosh Hashana 16a). Rather, Tu Bishvat is considered a new year for trees (as the Gemara says on 12a) because that is when most of the rain has fallen for that year.
See more here.