I starting reading about how trees survive the winter when the temperature plunges well below freezing (it's been about -20°C here most mornings for a month or more), and I discovered it involves some fairly complex scientific magic! Growth slows, trees go dormant, water migrates out of cells into the pores between cells, where it can safely freeze, sugars replace water inside the cells making them less likely to freeze, and in fact much of the actual tree does freeze - all the interior part that is dead wood. Only the living cells have to be protected.
A tree would be killed by its living cells freezing, but these adaptations provide cold acclimation, protecting the shrunken living cells, while allowing water (a tree is about half water) in between the cells to freeze harmlessly. The colourful fall of leaves in autumn is only the first step in a very complex process.
But it turns out my Butternut is doing all kinds of interesting things inside it's trunk and branches, to protect itself from the winter we enjoy for 2-3 months here. I'm impressed, after two days ago I'd thought 'nothing much is happening'.
If you've thought of joining in, pick a tree to follow, and join.
The link-up is open for one week starting the 7th of every month.