I'm not sure if this has been suggested before, but my search didn't turn up anything relevant so I figure I'd post.
I was cutting down and replanting trees yesterday using mulch and it got me thinking about potential uses for said mulch. When you're planting trees, it has the chance to change the terrain around the trees to change to a forest terrain. Would it ever be possible to maybe use mulch like we do seeds to plant grass so maybe when planting trees, the terrain wouldn't change? I mean, I suppose it's more an aesthetic thing as you can always just replow the tile after the tree is cut down and plant grass, but I just thought it might be cool to have a bit more control over how the biomes change over time. I'm not sure if there's something I'm missing in my thinking that could impact gameplay negatively.