How to remove wooden planks?

You have to use the pickaxe, it will take a while though

you'll here a different sound when your hitting the right spot as well.

Yeah, the axe is surprisingly not meant for removing wooden stuff. Also, you have to make sure that you stand close enough to the planks and they are the only item used frequently for building which take so long to remove.
You could try typing

Quote

setgametype 1

in the console to instantly remove items.

There are still some items that refuse to be removed. I have a few planks and a window that is out of place and cannot be removed. I'm hoping this gets fixed soon. An entire project is shot due to a misplaced window that won't budge.

Quote from Ivansky

There are still some items that refuse to be removed. I have a few planks and a window that is out of place and cannot be removed. I'm hoping this gets fixed soon. An entire project is shot due to a misplaced window that won't budge.

aim at a corner,you can remove them

I'll try that. Maybe I can salvage my build.

I have had fairly good success using the sythe in creative mode. I don't know why but it has worked on several stubborn beams

I've had a few difficulties with unmovable planks etc., I've found that Quiting so the game is saved and then reloading can sometimes help.
I also take occasional backup of the save files which can be copied back if disaster strikes.