Quote History Quoted:
My only knowledge comes from my cousin that has a small mill. He mills a lot of cedar and says for outdoor use, the redder the cedar the better, because the more yellow wood does not hold up to the elements as well. I've also heard before, that trees that grew in crappier ground will produce better lumber due to the closer growth rings.
View Quote
The sapwood on cedar isn't rot resistant like the heartwood (the red) so I would say that's correct
Regarding the growth rings, I'm not sure if you're still talking cedar but I know for fine woodworking there is more desire for northern grown hardwoods because they grow slower and the growth rings are closer. Hardwood floor made from Canadian oaks etc are more expensive than Tennessee Oaks...
Regarding siding, fence rails, etc. Sure, just do your research on what/how the old-timers did it. Many, many barns are still standing with the original timber framing and wood siding. You just have to keep in mind that using wood siding like that found on a barn isn't compatible with modern construction methods (vapor barriers, insulation, etc). The reason wood siding on a barn lasts for a century is because it's open to air on the inside and outside so any moisture that gets to it dries off quickly. If you block the back side of it with a vapor barrier and no air-gap you'll lost it quickly to rot. I would also watch species. Certain species rot quickly and are not suitable for any outdoor use.