Here's a picture of the Central City field for those of you who haven't been there:
The orange marker is roughly where "The Cauldron" is located. (just northeast of the center of the field)
Mario's house is on the upper left.
The heart-shaped open area behind his house is the staging area/safe zone. The bottom point of the "heart" is one of two entrance points to the skirmish zone.
Notice how the entire property looks like a rectangle slanted to the left...
The clearer area off to the right is where the neighbor's property begins.
Buffalo Creek runs along the bottom and is the lower edge of the skirmish area.
Bunker #1 is to the left of the orange marker...near the shop by Mario's house.
Bunker #2 is southeast of the marker.
Basically, all of the forest area south of the heart-shaped staging area is where we play out our battles
I hope that gives you a good idea of what the forest is like.
Of course, it's much different when you're actually in it.