I like the start.
I was thinking about adding MRM and EM in the tech/research to increase the health of the forest and improve absorption of pollution.

I have also thought of
I have recently wanted to plant more trees then is already there.
ATM you cut one tree you get 1 seed.
How about a tech that lets you harvest many seeds from a tree so you can actually have more trees t words the end of the game then at the start.

You get one seed and a random chance for a 2nd one. (1/4)
Also what's mrm and em ?
Sorry for the lack of updates, I kinda gave up on factorio quite some time ago ..

I think: Multiple reaction monitoring, (a method for targeted quantitative mass spectrometry) and Electron microscopy. Both are measurement and analysis methods which could relate to polution and to improving reaction based processes.

Correct me if I'm wrong on the abbreviations.

I didn't understand anything about this xD

Sorry for that! :)
It boils down to that, in-game, these could be methods to analyse polution and the way trees absorb it.
This could be the logic behind the techs unlocking some way to absorb polution better.
How this tech/research would improve forests.. No clue. Maybe it could enable you to plant 'better trees'?