There's plenty of trees most places. Dallas has the largest urban forest in the US.

And yet I can show you image after image of treeless streets and sidewalks. Therefore, there is room for improvement.

Is it possible that Dallas has the largest urban forest in the US, because it has the most urban sprawl? (I know nothing of this urban forest claim).

1) While, I can't personally speak (much) to walking around Dallas, I can speak quite a bit to walking around Austin, Texas. Walking around on a day that is 110º is doable, because the humidity is rarely ever that high, when the temp is.

2) Shade trees lower the temperature for the air under them, by as much as ten degrees.

I'm not arguing there shouldn't be trees,at at least where I'm at in DFW there's tons of them, I'm just arguing that dropping the temp from 110F to 100F still doesn't change the fact walking around in even 100F at decently high humidity will render most people a sweaty mess in a block. We had weeks where the heat index was around 120F this summer.

Even just sitting around outside in a shady backyard with lots of vegetation, a pool, and umbrellas we were still sweating profusely this last summer.

Trees prevent that 110F in the shade from become 120F on asphalt and concrete.

Ok, but you're still going to be a sweaty mess just walking a few blocks when its 110F and 50% humidity, and probably not going to walk even a few blocks in that kind of heat when you can otherwise traverse that with air conditioning.