Why don’t trees freeze to death in winter?

After all, if you or I stood outside naked for several months in sub-zero temperatures, we’d soon be turned into frosty statues.

Trees can’t burrow into the ground and hibernate like bears, and they can’t fly south like migratory birds. They’re fixed in place, at the mercy of the elements.

And yet they somehow survive through the cold depths of winter. Why don’t they turn to ice, since, like other living things, they’re made mostly of water?

Their trick is something called “hardening.”

In autumn, trees in cold climates undergo a change whereby water flows out of their cells. The concentrated sugars, proteins, and acids left behind act as a potent antifreeze. The water now in the spaces between the cells is so pure that ice crystals can’t form. This ultra-pure water can be cooled to -40 degrees F and still remain an ice-free liquid.

Pretty cool, isn’t it?

But what is it that triggers the hardening?

Ah, this is where we can learn a lesson from the trees.

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