Why Cities Need More Trees
So, the question got asked under the heat advice post a couple of times, making me realize this is not common knowledge, apparently. Because a bunch of people have asked "why do we need tree shade, sun gets through the leaves still!" And given I am Solarpunk posting either way, let me quickly go over this - because hey, this is actually a topic I have taken part on some research on. So yeah, I do know some about this.
So: when it is hot and sunny, obviously you want to see shadow. But generally you will often find that the shadow of trees feels nicer than the shadow of buildings. And this is because of the "urban heat island" effect, and because of the evaporation of trees.
To make it somewhat simple: when it is hot and sunny, it tends to be a good bit hotter in big cities than outside of the cities. This is because a lot of modern architecture is kinda concentrating the heat.
You might have noticed that concrete is fucking hot when it the summer sun is out. It basically absorbs heat energy and kinda holds onto it rather well. Concrete is used a lot in modern architecture not just in the streets. And obviously the very glass heavy fronts of modern buildings at times also focus the sunlight, and generally do just not help to allow the heat in the cities to evaporate. Which creates the effect of "Urban Heat Islands". Cities just heat up, and with the dense city centers often also not allowing for wind to properly move through them heat at times can collect there for days with little ways to get out.
Now, old stone buildings are already better. They heat up slower than concrete - though they, too, will heat up eventually and then at times hold onto the heat for a while.
Wood buildings do the entire heating up less, which makes them often nicer in summer, but obviously a bit of headache to keep warm in winter.
Now, here comes the part with the green cities.
And I have realized... some people really think that Solarpunk has all those green buildings, green streets and what not for aesthetic reasons, or maybe because of the insects.
Uhm... yeah, that is wrong. Solarpunk has those green cities, because green cities are better thermoregulated, and urban planners are already pushing for cities to become more green.
See: plants are full of water. And water evaporates in the heat. And whenever water evaporates, it takes some of that heat out of the environment to do that. So: if you are around plants in the heat, it is nicer and cooler. You will notice that if you seek shade underneath a tree, that shade often is indeed cooler than the shade of a building. This is why.
Additionally, if you have a lot of green in a city, you often also have some open ground - rather than ground that has been sealed. And natural ground also is better at regulating heat than concrete or even cobblestone. Because, again: there is some water in there. And that can evaporate.
Generally: if it is hot and sunny and you walk on concrete, or similar ground you are gonna burn your feet. If sun has been out for a long summer day, same will likely happen on cobblestone. If you meanwhile just walk on earth, you likely will be fine. On grass you definitely will NOT burn your feet.
So, yeah: green cities are amazing. Not just for the vibes, but also because they help the city cool down. And generally: even in a grassy field without shadow you will be cooler than in a concrete parking lot without shadow.
Plants help you cool down. Support plants.
Also, not really fitting with the rest of this post, but I wanted to share it still. It seems that a lot of the people who did not have the knowledge about this assumed that tree shade is worse than building shade due to sunlight still coming through the tree leaves, which I assume also is related to people partially worrying about UV. So let me quickly remind you: you are absolutely still in danger for sunburn even if you are in shade. Any shade. Because a bunch of UV light is still getting reflected all around you. (After all, if you are in shadow you are not in total darkness suddenly.) So please use sunscreen even if you stick to the shadow!
