Lightmapping is not working - Turns terrain very dark.

Hi. So I have two scenes, both I tried to lightmap, but only one worked. In the first scene everything worked as expected.

In my second scene, after lightmapping there are many issues:

1. The trees do not cast a shadow, even though they're the same tree as first scene where they do

2. After lightmapping, when realtime shadows of the directional light are turned off and "Baked only" is selected, the whole terrain just turns black.

3. The shadows are splotchy (When "auto" is selected and shadows turned off)

Here are pictures of the scenes:

2nd Scene with lightmap, "Auto" selected

2nd scene WITH lightmap, baked shadows only

I don't understand what's wrong here, can anyone help?