Trenching and bonuses

[randell765]

I realize you can treanch and it costs supplies but gives you added defensive bonuses. But can defensive bonuses be stacked? Could you be trenching in the mountains(eg +1) +1 for trenching for a total of +2?

Also, do you trench or is there a defensive stance when your in a city for added bonuses as well?

[SMK-at-work]

I don' really recall whether mountains have a defensive bonus or not - they certainly can screw up supply tho, whioch can have a major effect on combat.

Cities are sometimes fortified by having an existing level of entrenchment - any you can build on top of that add to it - but if you have a level 2 fortified city then you have to have researched level 3 entrenching before you can actually improve on it.