Terraforming works in another way?

[Fostik]

I am trying to terraform my land to forest tiles.

There are almost 25% but any forest tile was not generated. Is there something changed in game?

[Granger]

It's random, plus it seems to be triggered through decay (tree growth is, apart from stunting, deterministic and works with the map being unloaded - tile change isn't).
For best progress idle an alt 24/7 in the area to keep it loaded.

Or chime in here to help motivate the developers to fix this.