Strange as it may seem, both of those were the results of conscious decisions on my part:
1) The grass sprites/doodads are less saturated in order to make them more visible. In my experience, if they match the grass perfectly, they have a tendency to disappear at any viewpoint higher than ground level.
2) The forest floor texture is bright so that it looks realistic when viewed at ground level with trees switched on, i.e. when it is in shadow.