This translates as a defensive bonus given to units stationed in the forest. Open grass is the base terrain where no modifiers are present, while all others affect your units in one way or another. In Kohan, there are special units called support units. These units provide bonuses to whatever company they are attached to and are often a form of spell- user. One example of this would be the Wizard.
Wizards are the masters of thunder and lightning.
Other support units have other spells available to them, some that heal, others that summon monsters to battle. We wanted to have a more engrossing campaign, one that helped grow the storyline and keep the player interested. We also wanted some more focus on the Kohan heroes, considering they are the focus of the story, they should have more involvement in the game. Companies gain experience and when they advance to higher ranks, such as Veteran status, their basic combat attributes increase. The companies get better morale, offense, and defense.