hello ~first post~
I have used fresh cut cedar for building structures with no problems other than them being sticky because of the sap, but they have a roof and are somewhat protected from the elements.
Fence posts should be aged because the outer (white) wood will rot off, it's the inner (red) wood that is fairly rot resistant. If you must use fresh cut cedar for fence posts pick the posts with the least amount of white and the most red.
Also cedar is a softwood, very soft, so if you need to take out fence staples or nails or whatever later, it is pretty easy.
edit to add~ sorry, the bigger (diameter) the better for strength and if you can bury it another foot that might be better too. bark or no bark, it's up to you but I find it easier for cedar fence posts to be bark free.
