"Dry rot" is a misnomer. It still takes moisture to rot, and once rot starts, atmospheric moisture might be enough to keep it going.
Dry rot is the term given to brown rot decay caused by certain fungi that deteriorate timber in buildings and other wooden construction without an apparent source of moisture. The term is a misnomer[2] because all wood decaying fungi need a minimum amount of moisture before decay begins.[3] The decayed wood takes on a dark or browner crumbly appearance, with cubical like cracking or checking, that becomes brittle and can eventually crush the wood into powder. Chemically, wood attacked by dry rot fungi is decayed by the same process as other brown rot fungi. An outbreak of dry rot within a building can be an extremely serious infestation that is hard to eradicate, requiring drastic remedies to correct. Significant decay can cause instability and cause the structure to collapse.
https://en.wikipedia.org/wiki/Dry_rot
The fairings at the leading edge roots, against the fuselage, must be sealed exactly as the service manual stipulates. If there's no sealant, water gets into that wing and right up against the spars. If the sealant is applied all the way around and down the bottom, water that gets in there is trapped. If the wrong sealant is used, it can fail or crack or make removal difficult and expensive. Those fairings need to come off every annual to do the wooden wing AD. The sealant specified is the old dumdum stuff that never hardens. I encountered fairings glued on with construction adhesive. That caused some damage and necessary repairs, and it was obvious that nobody had been taking those fairings off to do the probe tests on the spar roots. It appears that nobody reads service manuals.
The sealant down the rest of the wing root has to be maintained, too.
