Cover the Birch early or later?

I'm located in Southern NJ. Around Sept/Oct I split a bunch of Silver Maple and River Birch - something that I knew would season by next year. My oak is for 2015 as I've just started in the last year or so. I still have more to split, but my question is this: Should I be top-covering this from the get-go or waiting until after this coming Summer? My pics should give you a feel of what I'm looking at. The larger piles are facing South. I don't have much property to store it or they would all be facing South. One thing I noticed, and you can see it on the closer pic of the River Birch, is that it looks as though it's molding on the ends. Maybe that's typical of some species as woods dry, but it's not happening on the Silver Maple.

Thanks in advance for your input!

Thanks Seanm! I thought I had seen various pics of uncovered Birch (white), but I have zero experience with Birch...let alone River Birch. I did hear and read that it rots pretty quickly if on the ground, but didn't realize the same if C/S/S. Again, your input is appreciated!

Thanks Dr. Savage! Always lookin' to learn.

90% of the birch is split. Most of what you see that isn't split is pin/red oak and will be split in the next two months. I have c/s/s the birch and just need to finish the 10%. I did top cover it as the snow was coming down on me tonight with some tarps - that was all I had. We're supposed to get 5-8 inches. I will be looking for some roofing materials in the next month for a more sturdy cover. Thanks so much for the comments. I'll take them all!