Again, thanks for all the nice comments!
Sinec everyone likes the bases, and I can imagine people wanting to do bases with planks for their pirates, here's an explanation on how I made mine :
°I went to Mc Donalds (which without any doubt can be replaced by the Burger-shop of your preference) and ordered a Cheeseburger
°I went to their coffee-stand and started stuffing wooden coffee-stirrers in my pockets
°I didn't stop when the guys behind the counter started looking at me and discussing about me
°I did stop when two came out from behind the counter and walked in my direction
°I went home (eating the Cheeseburger on the way)
°I took out my exacto-knife and started cutting the stirrers to the size of a 25mm base.
°As I wanted that rotten, decayed look on my planks, I only cut halfway through the stirrers, and then snapped them off. This way, you gat a natural looking broken wood on the edges.
°Here and there, I amended the breaks, adding more wear and tear with my exacto-knife
°If you want neat-cut planks, skip the snapping part and simply cut straight through the stirrers
And voilà, wooden-planked bases.
As for painting them, I started out with a Bestial Brown, and added more and more Bubonic Brown and Bleached Bone to that for the consecutive highlights.
I painted on the nerfs in the wood, but I guess you could score them in with a ballpoint pen.
Then, after the final highlight, I added green and blue washes to the more recessed areas (in between planks, in the wera and tear,...).
Once that had dried I applied a final, diluted Brown wash over the whole of the base.
I hope that that helped/inspired someone for their bases