I asked Chat GPT this question—an answer to a debate that has been discussed several times here before: “Why does firewood season faster after it’s been wet and then goes through a drying off process several times?” ANSWER: That’s a great observation. The reason firewood often seasons faster after going through wet–dry cycles comes down to the way wood’s cellular structure responds to moisture: Cell wall breakdown – When wood gets saturated, the fibers swell. As it dries, they shrink again. Repeated swelling and shrinking weakens the cell walls, opens micro-cracks, and increases the surface area where water vapor can escape the next time it dries. Checks and splits – Wet–dry cycling encourages small cracks to form, especially on the ends. These “checks” make more pathways for internal moisture to reach the air, speeding seasoning. Capillary disruption – In fresh or dense wood, water is bound tightly inside cell cavities and capillaries. Repeated cycles can break some of those bonds, so water moves out more freely when drying. Surface conditioning – If wood stays continuously wet, mold and fungi can sometimes start breaking down the surface cell layers, making them more porous. While that’s not always desirable, it can contribute to faster drying later. So, paradoxically, the stress of wetting and drying acts like a natural weathering process that helps wood “open up” and lose its moisture more quickly compared to wood that just sits in a steady state drying slowly.
I've wondered about this myself because I've observed it firsthand. I guess this logic also applies to dead and downed wood too, which has also gone through many wet/dry cycles. Top-covered it dries exponentially faster from a wet state than fresh/live cut of the same species.
I guess there is something to leaving it uncovered for a bit then perhaps covering a bit before getting ready to burn it. I know many folks on hear say they do that all the time.
The problem with this theory is when to stop the wetting/drying process. In nature when this happens you see the rotting taking place. The more it goes toward rot, the more useless the wood is. Therefore the will also be less heat given when burning the wood and I have noticed this very thing. Wet then dry a few times seems to do no harm but don't let that continue if you want good firewood. In days of old, when making timbers for building homes and barns, they didn't want to let this happen and that is why today we see beams in old homes and barns that are still strong and not rotted.
I think if it’s gotten to the point of actual rot taking hold its far too excessive. Something more middle of the road would be better. In other words, if your wood goes through several wet/drying cycles its nothing to worry about but may actually help it season faster. Where I live this process can happen several times in a single month over the summer. Then you can get it covered and put in your shed.
