I was curious given this week’s extremely low temperatures, and how yearly, trees seem to avoid death of their cells and structures in what would be otherwise destructive temperatures. How do they do this?
In: Biology
So, a couple of things, plant cells are not like animal cells. Our cells are soft and squishy, essentially like a thin-walled water balloon. Plant cells are more firm walled, more like a juicebox. That helps to make them more resistant to freeze damage right off as the membrane is tougher. Plants can tolerate a greater range of internal conditions than we do, as well as being able to survive and recover from serious physical damage better than animals, so even when they do get freezing damage it may only kill a part of them, not the entire tree.
They have some specific tricks they use, which are actually pretty much the same tricks many animal species that have ‘antifreeze’ use. Below is a summary of them copied from the article *[How do Trees Survive Winter Cold?](https://northernwoodlands.org/outside_story/article/trees-survive-winter-cold)*
>Schaberg’s work suggests three basic ways in which living tree cells prevent freezing. One is to change their membranes during cold acclimation so that the membranes become more pliable; this allows water to migrate out of the cells and into the spaces between the cells. The relocated water exerts pressure against the cell walls, but this pressure is offset as cells shrink and occupy less space.
>The second way a tree staves off freezing is to sweeten the fluids within the living cells. Come autumn, a tree converts starch to sugars, which act as something of an antifreeze. The cellular fluid within the living cells becomes concentrated with these natural sugars, which lowers the freezing point inside the cells, while the sugar-free water between the cells is allowed to freeze. Because the cell membranes are more pliable in winter, they’re squeezed but not punctured by the expanding ice crystals.
>The third coping mechanism is altogether different. It involves what Schaberg describes as a “glass phase,” where the liquid cell contents become so viscous that they appear to be solid, a kind of “molecular suspended animation” that mimics the way silica remains liquid as it is supercooled into glass. This third mechanism is triggered by the progressive cellular dehydration that results from the first two mechanisms and allows the supercooled contents of the tree’s cells to avoid crystallizing.
Here’s [another longer multi-part article that goes into more detail](https://www.canr.msu.edu/news/trees_avoid_damage_from_freezing_temperatures_part_1).
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