I found that when building with planks, beams, or woodlogs and we click and hold and drag to place multiple, we will use up the appropriate amount. However, if we go and remove the things we placed, with the crowbar, we retrieve only one item rather than the number we used to make the length of wall.
Trello update: The last weeks we've been improving the terrain generation and we've also put some effort into making landscapes smoother in general (to avoid bumpy terrain). Apart from that, we've also been working on new building tools. You find more information on Trello, but also expect an announcement about the recent changes soon