I don't know how much wood may have contributed to this but perhaps a similar experience that taught me a lesson. I built an enclosed shop room inside my 40x50 metal building last fall and it houses my shiny new PM lathe and a bit less shiny and much less new Bridgeport mill. I built it out of wood, all stuff you get from the Depot. It's a lot of wood, including the sheathing on the walls (chipboard). Where it contacts the concrete floor it's treated, otherwise all pine/fir stuff. We've been having a particularly wet late winter/spring here in Northern California. The humidity has been very high. The shop isn't climate controlled (except when I'm using it).
I recently went on a trip to Europe for a coupe weeks during this wet weather and that's when I learned a lesson.
I did not coat the shiny bits on my machines. That was a mistake. I came home to find a nice orange/brown color on much of those highly polished surfaces. My chuck, carriage and even on the ways had a film of rust. The chuck was particularly bad. I was horrified! I should have snapped some pictures but all I could think about was cleaning that off. Some WD40 and a bit of elbow grease and it is all ok. Thankfully on the ways it was just a slight surface discoloration. Much longer and I bet there would have been some pitting starting. I'm sure the humidity is/was the major culprit.
I now know I need to coat it if I'm going to be away any length of time. I don't use my machine daily so I do it pretty often. I really like LPS-2. I spray all the shiny bits and it leaves a pretty heavy coat that doesn't seem to disappear easily. Just a few quick sprays is all it takes. Easy to wipe off when I'm ready to resume using the machine. I spray my mill table, Kurt and other surfaces with it too. There's probably other (and maybe cheaper) options but I like this stuff.