“Planet’s atmosphere, though a gasping death to humans and most animals, is paradise for Earth plants. The high nitrate content of the soil and the rich yellow sunlight bring an abundant harvest wherever adjustments can be made for the unusual soil conditions.”
— Lady Deirdre Skye, “A Comparative Biology of Planet”
Centauri Ecology is the first worker technology. The game labels it an exploration technology because it represents knowledge gleaned about the new Planet, but in practice it is the key early production technology. It allows the production of terraformer units, which will serve the entire game long, aiding the player by enabling the improvement of tile yields (through farms and mines) and producing key infrastructure (like roads and sensor arrays).
As the quote tells us, Earth plants do quite well in the otherwise hostile climate of Planet. Thus, one of the key operations that terraformers allow are the creation of forests. Forests are an awesome terrain improvement that bring with them lots of benefits. Among them is the fact that, once planted, they can spread automatically onto neighboring unimproved tiles.
The other thing worth mentioning that is unlocked by this technology is the ability for terraformers to remove the native fungus from a square. The only native plant life that we see in the game is this strange red fungus that is difficult to move through (a fraction of move orders into fungus just fail) and that yields very poor economic returns. Therefore, in the early game, the game encourages you to remove it and replace it, wherever possible, with Earth life or technology.
As befitting their expertise in biology and agronomy, the Gaians begin with this technology. Presumably, the Gaians spent the entire first year after landing enthusiastically studying their new surroundings and this tech reflects the fruits of that labor.
It’s also worth mentioning that the Gaians have a couple of other small factional advantages that reduce their incentive to remove the fungus: they never suffer the movement delay through fungus squares; and they get an extra nutrient from fungus, which makes it less valuable to replace fungus with a better improvement. Still, though, in the early game it’s still in the Gaians’ interest to terraform the new planet. Just like all the other factions.
In fact, it is likely that “A Comparative Biology of Planet” was written soon after Planetfall. Perhaps it was during that first year, when key discoveries were being made seemingly daily. In any event, the purpose of the text is obviously to compare their new home to their old one and to figure out what lessons remain applicable and which need to be discarded or revised.
The other interesting thing about this quote is that this is the first time we see Lady Deirdre engaged as a working scientist, like Zakharov and Lal, in their own ways. It will not be the last time. In game, it is made clear by these quotes that she is the foremost expert on the ecology of the new Planet.