Some infantry are especially well adapted to jungle fighting.
Where your unit has the Jungle Fighters ability:
Treat woods and jungle terrain as fortifications for this unit. That is, when the unit is in cover in woods or jungle terrain, apply a +2 Infantry Armour bonus for cover rather than the usual +1.
1. Difference from Epic 40,000: This ability is equivalent to Epic 40,000's Kroot ability. We call it Jungle Fighters instead, so as not to imply that the ability is faction-specific.