Terrascapes upgrade from 2 food, 2 production, and 2 culture, to 3 yield each after 30 turns. The ecoscaping virtue increases upgrade speed so it should take only 15 turns.
For those of you that didn't play it, in Civilization 4 you built cottages which gave 1 commerce. When you worked them they would gradually upgrade to better improvements giving more commerce. The code existed in Civ 5 and CivBE but wasn't used. In this case the upgrading improvements grow without being worked.
Terrascapes are situational and expensive. Also they are improved by ecoscaping virtue way at the bottom of Posperity. This led to a lot of people never using them or only using them if they make it through all of prosperity, The AI seems to love them to their own detriment. This way you can get the full effect without needing prosperity, while prosperity, which seems intended to allow for faster or later expansion, allows you to build terrascapes without as long a wait for their full value.
For me, 30 turns seems a little short and makes the shortened time from ecoscaping less useful but Beyond Earth games seem to run shorter for most people so longer might make them still not useful.
They tooltip for ecoscaping says nothing because they never wrote one for a feature they weren't using and I'm not sure how it add it without possibly disrupting something else so I'm not going to add one yet.
Both terrascapes look the same. I don't know how to graphics so I can't change them. If someone wanted to make an alternate terrascape design I would use it and credit you.
I would rename the original terrascape an "earth reserve" and call the advanced one a terrascape. If possible for the earth reserve image I'd like a smaller area in the centre like the current terrascape image with either a paddock around it or buildings like are around the farms to give the impression that it is still in the process of being planted/growing, while the upgraded terrascape is complete.