[Avodah] Tu?bishvat is the Rosh Hashanah (new year) for trees. What does this mean?

[Micha Berger]

I don't know each stage of Tu biShvat's evolution. Was it always a holiday?
In the gemara, Tu biShvat is more like a shiur -- how do you know which
fruit go to which terumos uma'aseros?

But by the end of the geonim, tachanun was skipped on Tu biShvat. So,
even if it wasn't always a holiday, it started turning into one pretty
early. Well before the *publication* (so to speak) of the Zohar. So it's
not of Qabbalistic roots.

Tir'u baTov!
-Micha

-- 
Micha Berger                 "The most prevalent illness of our generation is
http://www.aishdas.org/asp   excessive anxiety....  Emunah decreases anxiety:
Author: Widen Your Tent      'The Almighty is my source of salvation;  I will
- https://amzn.to/2JRxnDF    trust and not be afraid.'" (Isa 12) -Shalhevesya