Psychrophobie, check four things:

1) Have you already gained a citizen today? I am pretty sure it is limited to one/day. The solution to this is (ta-da) wait a day.

2) When you say you have over 30 plants/trees, are you talking about veggies and fruit trees, or flowers? Tap on the cornucopia and see what the Food Status is - that is more accurate than how many trees/plants you have. I don't think this is the problem but it's not good to ignore the obvious stuff - my husband and I have been paid for more tech outcalls than you would think, just so the client could have us plug their printer in for them. grin

3) I'll take your word for it that the Beauty Level is not an issue.

4)
Click to reveal..
Have you done anything with the three boxes found in the Southeast Forest? If so, what was the final outcome - the last thing you did, saw, or read that seemed to be connected to those three boxes? I could be wrong about this, but I think that if a story line subplot is not completed, it can stopper up the progress of the game. You can PM your answer to me, or put it in a spoiler box like this one (use the full editor and the icon of an S with a slash through it).