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.
Melted crayon art. Not for young kids to do- your fingers get pretty hot, and you also get the occasional wax splash. Interestingly, the cheapo crayons (the ones that don't draw well) melted the easiest and were most vivid.