Any idea what happened? I managed to mess it all up by causing a measly BU and popped all my torches off. In the process of replacing the logs now, but it's not much of a problem as my wood farm is humongous.
Attached is forced crash log and the log.gz file from 2/26, the day I started 1.7.5 and went to my bridge. Note that I thought it was a texture pack glitch, and reloaded my pack, but that didn't help either. The blocks are just gone.
@Preben Gjelsvik Hey copyrighted!!! LOLno. Finished fixing the bridge anyway, so I guess it doesn't matter as none of my other worlds has any player-placed acacia logs. But rather annoying...