Here's the truth about fanfiction: 99% of readers are gonna skim right past that three word description of a flower or name of a forest that you spent two hours looking up. Because they aren't there for the scenery. They are there for the characters, the plot, and possibly (mostly? not me but some, lol) the porn. Help your author tell their story. Help them bake the cake so that it tastes good regardless of the icing. When people rave about the story and rec it to others, they aren't going to say, in paragraph 17 the author put a totally wrong tree in YOHE. They're going to say, this story made me FEEL xyz. Help the author get the feeling. If there's time and desire at the end, you can always go back and fix the tree.