Make regular trees have an effect on noise pollution.

[Sythrix]

They really should, I mean it doesn't make sense that the couple of trees on a road would reduce noise, but the ones you plant don't.

[30mm]

Agreed, realistic and useful.

[jon78]

In reality trees don't really have an effect on noise pollution except when you are dealing with an entire forest and then only for a few dB(SPL). What it should do though is limit air pollution. A forest planted in an air polluted area should rehabilitate it and limit spread.