So, I was looking through the modifiers for the different terrains and I came across something that confused me a bit.
So, on the battlemaps, Forest is indicated by sparsely populated trees while Foliage is indicated by densely populated trees.
While this makes some sense, since Forest only gives you -1 to ranged attacks and movement but +1 to infiltration and a maximum visibility of 3 and Foliage gives you -2 to ranged, -3 to movement, +2 to infiltration and a maximum visibility of 1, there is an issue with solid cover.
In Forest hexes, you can get into solid cover.
But in Foliage hexes, you cannot.
I interpret Foliage hexes as just denser Forest, so why can't you get into hard cover there?