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Comment by bob1029 | Hacker News Reader

I think there are other benefits to having a lot of trees around you.

As a resident of the Houston area, I am abundantly familiar with the idea of an urban heat island. The difference between a hot day inside the 610 loop and one 50 miles north is quite significant.

I moved from what is effectively the middle of the world's largest parking lot to the middle of a forest and I feel like I've transported myself 1000 miles instead of 50.

I've also developed a strong sense that the forest seems to have some kind of influence over the weather patterns. Not a strong or active one, but it definitely seems like a thing when you're watching Doppler radar.

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The science behind how forests impact weather is still developing, so I can’t make wild claims like I want to. Yet the evidence is extremely compelling. Trees seem to induce rain, reduce turbulence from winds, and as this article mentions, cool the air far more than we thought.

Trees seem to be—unsurprisingly—specialist organisms in the art of maximizing local hydrological features. They help create wetter environments so more trees can live there, and things can get a little more wet still, for more trees, then more water, and so on.

The research I’ve read is mostly along the lines of “we’ve observed these really interesting patterns and we suspect these are the underlying mechanisms”, but as I recall, proving the cause and effect of such large scale phenomenons isn’t trivial. I’m also not someone who researches this stuff, so my take on it is essentially irrelevant. The bottom line is: lots of evidence and research supports your observation, and it’s an extremely interesting field of research. I think it’s the key to making life better for a lot of life on the planet.

> reduce turbulence from winds

I'm convinced this is a very strong effect. The forest definitely protected my home from some nasty windstorms we've had. Out toward the lake where there is less coverage, essentially everyone was knocked off the grid for a whole day while I was unaffected - Despite having my power being delivered by similar overhead lines that follow a very narrow clearing through the middle of the forest. You'd think it would be a shooting gallery but it's the opposite thing. Isolated trees seem way more lethal to grid infrastructure.

I mean... this cannot be a surprise to anyone that a physical object affects wind?

Farmers in the Great Plains have been making wind shields for their lands with trees for a long time.

When you've lived in the country most of your life, it's weird when you hear people discover basic things like windbreaks or the fact that tree shade is cooler than other shade. My great-grandparents would have said, "Well, duh."

Well, what we're talking about isn't micro, local-scale effects but more like climate and weather. I agree, those things are totally obvious, but it isn't always obvious what they mean at broader scales. Even some of the obvious local effects can totally transform once they culminate, leading to non-obvious results of very obvious local properties of trees.

These shields are slightly different from what's happening on the weather-system scale. Those winds are low to the ground, and when you obstruct them, the wind is deflected upward and diffused by the trees absorbing some (a very tiny amount) of the wind's energy. So it's a highly local effect. Forests can also modulate properties of the atmosphere around them, which can do various things like alter cloud formation or even stimulate rain. Rain stimulation is still be studied as I recall, but it has huge implications if it's true.

It might be a surprise when looking at the stratification of the atmosphere, where winds can occur, the depth of the atmosphere, and how tiny trees are on that scale.

On one hand, the mechanism seems readily apparent. On the other, it's also astounding. It's not just that the trees create physical disruption with their own physical bodies, but also through how they modify the properties of the atmosphere above and around them. That's incredible. They transport immense amounts of water into the atmosphere.

There's been a lot of study on this topic which is interesting! As you say, they collect moisture in a lot of ways. Part of this is done by the structure of the tree [1] (the surface area of the leaves is surprisingly large and catches a lot of moisture and other particulates in the air), rain drops hitting tree leaves cause droplets to break into a fog or mist, and some varieties of trees found in rainforests will also release various chemicals and compounds [2] that can encourage cloud formation and rainfall. It's fascinating stuff!

1. How Trees Bring Water: https://www.youtube.com/watch?v=oY8ds4BiG1A

2. Amazon Seeds Its Own Rain: https://www.science.org/content/article/amazon-seeds-its-own...

I experience the opposite effect.

Where I live the forest effectively disappears every autumn, and then it gets really cold. Six months later the forest grows back and then it gets really hot. The ambient temperature is obviously intimately correlated with the presence or absence of the forest.

Amusing but obviously flawed - the science here is about the long time period correlations of mean forest coverage and mean regional tempretures (as you very likely are aware), not the short term seasonal cycle.

I chuckled .. others downvoted. Humour on HN is hard :/

This becomes even more apparent when you move to cities that are more integrated with local forests in part. You drive by the foresty adjacent area, not even in the forest, and the temperature drops dramatically, easily 5+ C. And as CO2 increases, so too is greenery. [1]

[1] - https://science.nasa.gov/earth/climate-change/co2-is-making-...

Not only forests but even just tree cover. I live in Berlin and there were a few days a few years ago over 40 degrees, and I remember the difference was stark going from my relatively tree-lined street to an area of the city with only concrete.

Houston eh!, well let me tell you that I use the GOES sattelites for local weather observation, and general real time views of varios conditions..... and Houston is the one city that stands right out, instantly visible and radiating in the infra red, never been there, but your spoke roads must be fucking HUGE, to be vissible from geosynchronous orbit, the whole thing working as a heat absorber/radiator. as a "controll" try as I might, Mexico city (others),remain invisible in the same images

> your spoke roads must be fucking HUGE

I don't know of any place on earth with more installed concrete or greater ability to deploy it.

About the weather patterns. We live near a large area of natural dunes. In school we were taught that the natural dunes reflect sunlight, leading to rising air. Although I can't remember the exact meteorology (rising air generally leads to rain) they showed us the precipitation patterns and the surrounding areas get more rain and the dunes less. As a layman, I except forest vs. concrete will lead to similar situations. More rain near forests, less near concrete. Is that what you see on radar?

I now see that u/steve_adams posted pretty much the same point. I wonder how I was taught this 25 years ago in high school, with local graphs for evidence, and it still isn't scientific consensus. Super local weather models aren't a thing? (This is in jest, they obviously are a thing. Perhaps it's harder than I imagine.)

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