Lush is a straightforward concept, nobody but you (and your allies?) can build on it. But it also helps on settlements. If someone kills your TC so that they can quickly replace it with your own, they will have a hard time because of this green substance.
Next is Gaia Forest. A natural "wall" and also aserves as a resource (it also looks nice).
Buildings also regenrate, which is helpful with stuff like towers that are occasionally picked on by raiders.
But what makes Gaia an eco. power are two things. 1. The lesser is the fact that fishing ships and trade carts are stronger and faster. 2. The much greater is that all eco. improvents are 30% cheaper!!!!!!!!! That means only 70 wood and gold for hunting dogs, saving you big money early on. And it makes it much easier to find the resources to purchase shaft mine and two man saw in Classical.
Gaia's tech, channels may actually be better to get later on when u can afford the favor cost, and it makes villagers faster.
Along with Gaia forest, she gets the god choice Leto, who gives you defensive spiders.Placing these in a tight point between the gaia forest trees and another building can lead to serious death among your enemy as they squeeze through.
Also Hesperides in heroic lets you protect your titan gate from offensive god powers (because it blocks GP's).
This is a major advantrage she has that Kronos doesnt (so Kronos is not ultimately OP, eh?).
I told you I'd be back.