Battenkiller said:
So the water content may be roughly the same, but late-cut wood is drier on the outside. Since it's a known fact that wood dries across the grain lines by diffusion along a moisture gradient (wetter on the inside than on the outside), seems to me it will dry faster if that gradient is already established. Therefore, late-cut wood should dry faster, even though it has the same starting moisture content as spring-cut wood. For the past 25 years, the majority of my wood has been cut in the fall or winter, and I don't notice the drying times to be as long as some claim is necessary.
While you aren't exactly wrong, I think you may be leaving a few things out of the thought process on this.
#1 After splitting the wood, what was the "inside" and "outside" are no longer the same. You can have wood that was considered outside wood now being considered inside wood. You can also have wood that was considered inside wood now being considered outside wood.
#2 Because of the above statement, being able to really make a comparison between fall and spring cut wood, I think we would need to compare wood that is seasoned in the round (or at least seasoned in a similar shape etc). So lets just start off with comparing rounds. If you use fall cut wood, that has a higher MC inside, it is true that the gradiant is already started, however I think this actually would slow down the seasoning. The reason being is that that higher MC in the middle has to diffuse a further distance. Whereas with spring-cut wood, the higher MC on the outside would diffuse out more quickly, leaving the center with a lower MC. Because the center is what takes the longest to season you want the center MC to start off as low as possible to begin with.
It's hard to explain what I'm trying to say so I'll try an analogy.
When placing the stove in your house you always place as close as possible to the place you want the heat right? You want the heat source to be as close as possible to where you want the heat to go because you don't want to have to worry about it diffusing or being transported to where it needs to be. The same can be said for the moisture, because it leaves the wood on the outside (if it's left in the round), you want as much moisture towards the outside as possible because that is going to diffuse faster.
But my real opinion is that it doesn't matter. I burn free wood, and when you have free wood presented to you, you typically don't wait for it to be the proper season to go cut it. You take it when you can get it where you can get it and you let it season. The difference in MC and all that is negligible once the wood is split.
BTW, I'm not trying to be argumentative, just trying to present things from a different approach in case you hadn't considered them.