Resource trading logic and AI question

In my Mod, I want to have promotion strengths assigned based upon the number of strategic resources one has... for example, a LUMBER resource would give a small defense modifier promotion to a naval unit, while 2 such resources under player ownership would give a slightly higher strength promotion.

The only thing is, in this case I no longer want the lumber resource, though it is strategic, to be a requirement for units.

Does AI trade logic account for the fact that it does not need a strategic resource for units? I certainly want the AI players to still want to acquire these resources.

Alternatively, I could likely change the resources in question to luxury resources that give 0 or 1 happiness? In that case, does the AI take into account the happiness a luxury will generate for them. Additionally, I see a problem with this route, as resources will only be traded on a one by one basis, not in lots of more than 1, unlike strategic resources.

Does anyone have any knowledge of AI resource trade logic in the above situations?

I don't have the knowledge you need for resource trade in those situations; however, it's interesting that iron has 10 for the offense flavour and horses have 10 for the mobile flavour. Possibly, this gives the AI a clue as to which one to go for as a priority based on their leader's flavours? If so, maybe you could give a high flavour for naval to lumber?

That's a good idea... it will certainly give incentive to the AI to make trades. Still, that'll only work if the AI logic does not account for the fact that the resources will not be needed for unit production.

Which brings me back to the original question...

My guess is that the flavours, plus what resources they have, are the things that it accounts for. If an AI civ was in an area with, say, four iron mines each offering 9 iron, it will still improve all four mines - it won't decide that it has enough iron for the units it needs and stop. Perhaps another inducement for the lumber is to make the hexagon containing the lumber have +1 production if it's improved.