Grow ecosystem tier question

[Visenja]

... and since i have two ecosystems at tier 2 - i have to excuse my stupid question - but i cant seem to lvl to tier 3 at any of them, all requirements is fulfilled at both, except the box named : Ecosystems grown to tier 3 (2/3)

Ruins ( all in the first two maps) and Sacred Forrest x2 is done...
Not done a lot of village building though ...

Any help to get the last "tic" to grow ecosystem to tier 3 ?

[Tenoshii]

I'm not 100% sure where you are based on what you've said, but I'd speculate what you are seeing means you need to plant and upgrade a 3rd colossal tree to Tier 3.

If you don't have the Arid colossal seed planted yet that means you need to do the Forest God's quest so he can plant another Sacred Forest where you can get the 3rd seed.

[hotaru251]

it gating you until you start your 3rd type of biome (arid)

its by design.

[xitooner]

Yeah, the arid biome is what makes it "tier 3 (3/3)" instead of "tier 3 (2/3)"