I can't find the law, but was told a few times that in Oregon, one needs a permit to HAUL any type of wood. The law is mainly to stop stealing of cedar and logs. More recently curly maple (music wood) has been added to the list.
We have a law here in the north of you that you need a permit to haul cedar and maple. It can be enforced. It was explained that if you are hauling off your own land, you go to a sheriff's office and they will have the paperwork.
I have hauled a lot of maple firewood and have not been stopped. Usually, if they see it is cut into firewood lengths, there's no need to be stopped. It is obviously not going to be sold for music wood, which may rival or have surpassed cedar when it comes to getting stolen.
I guess if they want to check you out, it makes for a good excuse.
Don't know how many of you responders know how the cedar thieving used to be, and the Tweakers now look for maples. If you see a little areas of moss hacked away on maples, that usually means somebody's been looking to steal some and checking for the indicators of it being curly grained. Maple is easier than cedar to steal because the desired size is easier to pack out of the woods.