How to fix disappearing texture on the terrain.

Hello, I know this is a bit old, but maybe it will help other people out who come across it.

As for the microscopic trees you need to increase your model (NOT the prefab) scale factor in the inspector. For some reason Unity gets the size from the default model instead of the prefabs you use.

As for the terrain texture disappearing, im not sure what you mean, is it becoming transparent or just one solid color? If it is becoming transparent when you "get to close" it could be that your camera's near plane is too large so your camera is actually rendering past the terrain.

If it is just becoming one solid color, you could try changing your Base Map Dist (in the terrain's option tab), but it usually does it backwards (becomes one color far away).

Hope this helps anyone who comes across this.