First time painting plein air (watercolour)

Wandered into the New Forest w/ my bro over Easter - no leaves on any trees. The day was grey/cloudy, changing later for some intermittent but very strong angled light. 

Went down the length of a little winding tributary, finding somewhere to park our collective arse and whip out the brushes.

I drew a couple experiments in composition, thinking back to Will Eisner's great PDF on sequential art. Initially I wanted the patch of light behind the fallen tree to be the focus, using the dark trunks either side to act as a framing device:

Then I remembered that I haven't used watercolours since junior school - so I cut the composition back to focus on the fallen tree on its own - quickly shading in the darkest values:

For the painting I used a 1cm cheap-o synthetic brush, watercolour straight out of the tube, and water straight out of the bottle:

As a quick 20 min sketch/painting I'm pretty pleased with the final result (so pleased I even signed it, would you look at that) - but - perhaps an opaque medium (gouache?) would have been better in this case, you can tell looking at it that I was worried about preserving the edges/boundaries between the colours - the pale halo around the root ball as an example.

Turned out alright, can't wait to do it again - I'm frothing at the mouth, it's unhealthy.