A number of communities in Arizona are certified as Dark Sky, preserving the ability to see the stars at night. Research has showed it also improves human health. But did you know that trees need to sleep too? Apparently when cities turn off their lights at night, the trees are healthier and live longer.
It makes sense. I remember a high school science project where we measured gases off plants during the day and night. Plants change their metabolic processes at night. If there's no 'night' then the plants can't do that work.