Green shelter

Home in Belgium again, good weather and husband and I took another trek into the woods, this time following very small and very muddy horse and mountain-biking tracks. Luckily there was not a horse or a mountainbiker in sight, because it was hard enough going without having to worry about other users. We stumbled upon this curious green caravan in the middle of the woods. Could be that it's used for twitchers or maybe hunters?

I've processed it into a green mono, I'll post the full coloured version in Blipfolio