I do quite like the "all seasons" tree . This was my first initial thought for a logo (just not a painted style like this) but I'm pretty sure it's been done more than once so it'd need some work to make it original.
Surf watercolor painting - Giclee print Surf art surfboard painting Wave Aqua Blue Zen drawing by Michelle Dujardin Surf Aquarelle
I find this piece in particular to be relevant to what I am basing my design from. As my chosen festival is a surfing and music festival, I think a use of watercolours would be an appropriate (and also relevant) choice for print making experimentation.