This is a multiple exposure image, constructed in an iPad app called 'Enlight'. It's made up of four different photos of mine, all related to trees and autumn colours, blended together. I recently bought the app and I've just started to play with it. It's just fun to do something different and experimental. I'm not being very intentional about it so far, though I think sometimes it gives rather interesting effects. Things either seem to 'work' quite quickly or obviously don't, but you don't know what's going to happen until you start experimenting. This is only the second image I've made using this particular app, so I am quite pleased with the way it turned out.
There are photographers out there who are seriously into abstract photography, using multiple exposures that have been created either in-camera or in post-processing, adding textures or using intentional camera movement to create interesting and unusual effects. If you're interested, there are lots of beautiful examples on the internet. One of my favourite photographer-artists is Doug Chinnery and I also love Valda Bailey's work. Do take a look at their websites if you have a minute.