Not to be confused with Forrest (Fates).
Forested maps are always outdoors, either in large open areas or cities which feature small groups of forested tiles. Forest-spaces mainly appear in the 2D Fire Emblem games like Fire Emblem: The Binding Blade, Fire Emblem: The Blazing Blade, and Fire Emblem: The Sacred Stones.
The Forest-spaces provide a +1 bonus to Defense and +20 bonus to Avoid, allowing the unit under cover to take less damage and have a greater chance to avoid enemy attacks. Like all terrains, the effects activate when both defending and attacking while standing on the space.
It is also noteworthy that entering or passing through a Forest requires two remaining move tiles (three for horse-based units), meaning the Terrain also reduces movement. This can be avoided most of the time however by going around forested areas.
Forest-spaces that exist in Fire Emblem: Path of Radiance or it's sequel Fire Emblem: Radiant Dawn are uncrossable, although those games featured the Thicket which is similar in effect to a normal forested space.