That's not a problem of the scenery.
It's just that you have disabled the "Dynamic Reflections" in the sim Graphic option, so the sim will revert do the default Global environment map, which shows a forest scene.
You don't see the problem in other FSDT airports, so you are assuming KIAH has a problem, but that's just because some of them (KLAX, for example) come with a custom environment map which is more proper than the default one that looks like a pine forest. However, doing this would *prevent* the Dynamic Reflections to show up, because the sim will always use the custom (static) one, instead of the Dynamic Reflections, so in KIAH we removed the custom environment in order to allow the Dynamic reflections. But of course, if you turn them off, the sim will revert to the default one.
