My usual approach would be to start with the structure and draw the trees first but I’ve gone for a more traditional watercolour technique, painting in the background in light washes, as if the trees weren’t there at all.
Next came splodges of green, the top ones darker against the sky, and then, after allowing that to dry, I painted in the trunks and branches in a dull, dark brown.
The rooks appeared as I was starting to go back over the whole thing, trying to bring it all together.