It doesn't take a solid roof to hold a snow load. If he's going to alternate 1x1s, as is often done for shade, they'll hold snow just like if it's a solid roof. Neither mine or my buddies (pics above) have roofs, but both had literally feet of snow on them this year. It just depends how close to each other the 1x1s are.
Visited the local lumberyard yesterday, they can't easily get cedar and agreed with many here to suggest fir. They also do un surfaced but could surface it for a cost.
