Stern,
there are many commercial products for sealing/staining your timbers to protect them from the weather. talk to your local paint store for guidance. the same products would be used for log homes too.
what is you plan for the base of your carport, gravel or cement ? it would seem to me that this surface would be fairly level. while you are digging to establish the sub base you can also dig the holes for your post footers. using a csrdboard cylinder or pyramid form pour your reinforced post bases to extend above your average snow level. the map tells me you are at pretty high altitude so I suspect you have some significant snowfall. each of these pier tops would be at the same altitude so your posts bottoms will be in the same horizontal plane.
your uneven ground problem just vanished.
yoo can assemble your timberframe bents or wall sections on any temporary cribbing and raise them from there.
good luck, work safe
deralte
