I've never dealt with fresh cut lumber that I may use for woodworking

I got a call from a new friend, who I met at a party two nights ago, and he told me he just had an Ash and Walnut tree cut down and had tree guys in who were going to cut it up and haul it away to dump.

I arrived and took about 6 pieces of Walnut, 18" in diameter and about 3' long and 6 pieces of ash about 22" in diameter and about 18"-20" long.

I have no real plans for it and am not really sure how to store it, covered etc., it will be outside.

My thoughts are to use it on my lathe, but not in the near future, or did I just get myself some firewood?