There are some great grabs from Google Maps of trees. I haven't tessellated them yet but they will be great.
January 2012 update
I have recently completed a set of game graphics for an as yet unpublished and therefore unnamed title. This is to be a dungeons and dragons style pixel art side scrolling platformer . If that sounds overblown it's because I'm sort of still enjoying picking up the lingo - games world v different from the VFX + video world I'm from. But having played and designed tons of role playing games in the past, II felt pretty confident in getting this done.
|recombined tiles - still a few seams showing along shadow areas.|
|close up of two joined tiles|
|a test level made up using every tile type|
|close up on ruined wall area|
Isometric Dungeon Floor Tiles
These were created as an experiment and worked very well. The next stage would be to include walls at the back of each section - or maybe some doors or other upright set dressing. It is really just a floorplan set to a 45 degree angle making amny triagulated combinations of square floor texture tiles.
|A test layout using the tiles - endless dungeons possible|
|actual tiles - each square one of dozens of combinations - this is only half of the full set- every square tile can tesselate with any other.|