Trees are the tallest, oldest and in many ways the most efficient of all living things. Powered by the sun, they are the planet's biochemical engines, drawing water and minerals from the soil and converting harmful carbon dioxide into life-giving oxygen. They live simultaneously in the earth and the sky. And each mature tree is an ecological city, home for thousands of interacting plants, animals and fungi.
The average tree grows its branches out until it encounters the branch tips of a neighboring tree of the same height. It doesn’t grow any wider because the air and better light in this space are already taken. However, it heavily reinforces the branches it has extended, so you get the impression that there’s quite a shoving match going on up there. But a pair of true friends is careful right from the outset not to grow overly thick branches in each other’s direction. The trees don’t want to take anything away from each other, and so they develop sturdy branches only at the outer edges of their crowns, that is to say, only in the direction of “non-friends.” Such partners are often so tightly connected at the roots that sometimes they even die together.
from 'The Hidden Life of Trees' by Peter Wohlleben
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