is it true that pine trees can help cool the surrounding air when growing in tropical to sub-tropical climate? i’ve been to some places in tropical asia where pine trees were planted at near- sea level and yes, it feels cool (or is it just in my head?) even in okinawa japan, which is sub-tropical, pine groves feel more pleasant than those where you have tropical hardwoods.
I’ve never heard that, and I’ve done a lot of reading in tropical forestry. I can’t think of anything physiological about pines that would cause such an effect. The only thing that might be related is that pine woods tend to be more open, so that there might possibly be more wind.
Do pine trees have as much capacity as hardwoods to add to the humidity through transpiration?
East Texas is just as godawful hot as anywhere else in Texas or Louisiana, and it has a crazy number of pine forests.
This. Conifers do nothing for Texas.
Or, maybe they do. It could be that instead of 100-110 degree temps in June, we would otherwise have a 110-120 degree range. Who knows. 
Less, I’d have thought, as I think pine needles are adapted to conserve moisture.
Yeah, but those are southern pines. Northern pines are more cooling. 
Indeed, look what they did for the fjords.
Great habitat for Norwegian Blues, y’know.
My thinking was it could feel cooler because the pine trees aren’t raising the humidity as much.
That’s where I thought you were going, but I can’t imagine it’s going to have a noticeable effect unless maybe you’re in the middle of a huge forest of them.
I’m pretty sure I’ve experienced this- a pine forest feels cooler than a deciduous forest. I think it’s because pine trees provide roughly the same amount of shade, but don’t block the wind near as much.
When I think of pine trees, I think of the oppressive heat when I’d visit my grandparents in Medford, Oregon. (Good thing they lived by a creek.)
I read Tales of the South Pacific a couple of years ago, and Michener mentions an island that had pine trees planted on it. I think they were planed for the lumber. I don’t recall if he said anything about the temperature.
I think cedars lower the temperature. I live on the coast, just below the Canadian border, and I can tell you it’s plenty cool here! 
Was that the one about Norfolk Pines? Where the USAF had to cut them for a runway and all the old villagers came down to see them a last time before they were gone?
I believe it was.
Errata: ‘planed for the lumber’ should be ‘planted for the lumber’. Although I assumed planing was involved later.