So you say about two human beings only not really there to procreate the rest of mankind. So maybe many of the same trees, according to your thought, emerged at the same time or around the same time, even though different types of trees. Besides, it was one human that the Bible says God made, from the earth. Eve came from Adam's rib. That you don't believe it doesn't mean it didn't happen that way. Yes, Moses knew that the earth was probably looking a like Mars before God cultivated the earth, making it ready for "life."