Sometimes you can tell the grain by the pattern of the bark, on a standing tree.
It's not full proof though. I cut a wavy/snakey grain osage log. I was sure this was going to produce a motherload of beautiful snakey character staves. The problem was the grain of each ring ran opposite to the next ring. The log couldn't be split cleanly, or reasonably straight. It just wanted to tear itself apart across the length at a 45 deg angle, no propellor twist. I sawed it up into 2" thick boards, and gave them 3 coats of pva glue all over. Despite that it still checked badly on the faces, due to the exposed cross grain.
