Wouldn't you like to see WHO cut those trees down? I believe it was God's mighty angels cutting down the trees so the giants had no escape from the flood waters.
But try to imagine a world FULL of those enormous trees!! I don't think our imaginations can come close to what the Garden of Eden and preflood world looked like.
1 Corinthians 2:9 No eye has seen, no ear has heard, no heart has imagined, what God has prepared for those who love Him.
We're talking God's creation. Before the degradation of sin that's been going on for thousands of years. Can't wait until all truth is revealed!