Forest expansion rate question

[Stumpy123]

Hey all, I recently started playing this game again, and applying what I learned from Civ 3. Having fun so far, but have a quick question: does having several forest tiles next together improve the rate at which forest expands into empty tiles, or is it the same as having only 1 tile of forest? I've always thought clusters of forest expanded faster.

 

[Proletariat]

That's what I had always assumed. Good question, though. Anyone?

 

[Empiremaker]

You could try turning up the forest expansion rate, and observe how many turns on average it takes for a forest to expand to a given square if 1-8 forest tiles border it.

 

[Cuivienen]

Yes, it does. I'm not certain about the exact odds, but each adjacent Forest tile adds a slight (probably 1%) chance of Forest growth in each neighboring tile. If there are 8 adjacent Forest tiles, a tile will have 8x the chance it would have had otherwise each turn. I believe having Fungus in a tile halves the chance, and of course Rocky tiles have no chance of Forest growth.