If you're new to watercolor, this is actually a great piece to try out! It's surprisingly easy!

First, you just paint in your trunk (as you do the branches, put more water in to decrease the strength of the brown color).
Once that dries, then just start throwing that pink (or whatever color you want!) paint on there it doesn't have to be "neat" or "perfect" - in fact randomness is even better! In some of the wet areas put a dab of paint into it and watch it spread to get a darker value pink (wet-in-wet) Then do whatever else you want to do, splash some paint on there from your brush to give it a cool effect, drip some paint from above your paper....whatever you want to do! Finally, if you want, you can go in with a pencil and outline some of the water to give the tree shape a little extra form and to create a bit of a contrast.

I am currently editing my Intro video to my new series "Learn art with me" and one of the first things we will make is a watercolor tree like this one (I think we'll actually do a few watercolor trees in different styles - one is going to be "stained glass" style), so keep an eye out if this is something you'd like to try!