It looks like a "system units" issue of used surface or models. First I would suggest to apply the Reset XForm utility on your surface. This will "reset" it's local coordinates / scale and should fix that issue. Then please try to recreate the Forest object. To avoid similar problems, specially while using imported surface(s), it's handy to double check this way, there is no coordinates / scale problem with the surface mesh.
If that doesn't help (the surfaces has correct scale), please double check measurements of used models.
Regarding the brightness / saturation issue - the lightning seems to be different overall. Might be, you've changed the Color mapping settings or so?