With regards to temperature, there are more levers to pull, like the aspect ratio of the street (narrower = cooler). Architects in Taiwan and southern China have been studying arcaded streets (qilou/騎樓), which seem to be as good as trees for shielding pedestrians [1], except in situations where the sun might shine through the sides or ends.
Of course, trees are great for many other reasons like air quality, but for temperature fundamentally they're just big evaporative coolers. I wish cities in more water-stressed areas would consider arcades + rooftop solar.