A tank that is in woods receives Cover, as per the woods rule. Period. Doesn't need to be at least two of the corners, as per the cover rule, just on the template that specifically grants cover The one tricky aspect is when a tank that is in woods shoots a tank out of woods. Since the shooting tank ignores the terrain directly underneath itself, it can be positioned in a way that it isn't shooting through the woods, and therefore not obstructing Los to the defending tanks corners, which would be the way the defender would receive cover outside of woods. The same is true for desert scrub and fields, except those can be fired through entirely, unlike woods.