I need Damascus up to 10 pop from its current 9 so I can build an IZ.

It has plenty of housing.

It is unhappy. Growth in 20 turns.

I have a rainforest square. It is swapped to Damascus. I have a worker on it. The worker shows a huge yield in food and production to chop the tile.

I chop the tile.

The production makes great progress towards the current project, a university.

The food makes no change at all.

Have I misunderstood the mechanic here? Does happiness determine chip growth?