Trees are magnificent creatures. I've known this for a long time, in theory - Did you know that they not only drink water like you and I, but also expirate it back out into the atmosphere, and therefore return moisture back into the atmosphere, form clouds, and together with the wind, help move rain further inland away from the coast. In other words, without trees, it would mostly rain along bodies of water, but other places would become more and more dry... Even more than that, their roots, the longer, thicker, and deeper they are, help hold the soil together so it does not just wash off when there is a big rain, and help hold water in the soil, so that everything growing nearby can survive longer during periods of drought?
But, that's all theory, and I've been learning through my own blood and sinews! Trees are AMAZING. They provide shade! There are 3 factors which effect the difficulty of my days walking: 1) The state of my body's recovery from the previous day, 2) How much I'm going uphill, and on what incline, and 3) the heat! The last is made significantly easier by shade. When I have shade, 95 F in the sun, can feel like a nice 75 F in the shade. It's the difference between I can barely breathe and being able to take the challenge in stride. This doesn't even include the beauty! Of course I'm not the only one who enjoys shade. I'm just a human passing through, but Trees are an essential part of sustaining entire eco-systems of shorter plants, animals, bugs, and micro-organisms.
Did you know? A typical four-square-mile patch of rainforest contains as many as 1,500 flowering plants, 750 species of trees, 400 species of birds and 150 species of butterflies.
It's not just rainforests, some "70 percent of Earth's land animals and plants live in forests, and many cannot survive the deforestation that destroys their homes." They provide almost unmeasurable "services" to humans beyond shade as well - read more HERE.