Trivial question but it's On Topic!

[James "Cubby" Culbertson]

Hiya Folks, Was out last weekend gathering the logs I need to build a bed and a few end tables for a cabin in the woods. I will have to remove the bark and let them dry before I can do much else but while I was wielding the chainsaw searching for the next piece, I wondered something. When it's cold, does the moisture inside trees freeze? I kind of suspect that with all the other substances generated within the tree, it actually becomes a natural anti freeze if you will but wasn't sure. Just curious more than anything. Cheers, cc

[Leuf]

Took some persistance, but Google eventually gave these up:

"As fall draws on into winter, the tree's cell membranes become more and more permeable to water - that is, the colder it gets, the more water will move outside the cell. The cell membrane collapses like a deflated balloon over the vital contents of the cell, preserving it until spring."

[Leuf]

"Trees make a natural antifreeze to survive freezes. They do this in two stages.

The first requires a gentle cooling-down to below 55 but not to freezing. The tree starts to gather sugars and break down stored starches.

As the weather chills over a few days, trees start to change their living membranes to maintain a liquid, cold-temperature form.

Trees easily damaged by cold usually can't modify their membranes, which become impermeable solids when cold and suffocate the cells.

Stage two happens below freezing. Trees use collected sugars and proteins to bind water inside living cells and prevent ice crystals from forming.

Between the cells, ice can form and pull water from the cells. If too much ice forms, new or sensitive tissues are mangled."

[George E. Cawthon]

Damn right it can freeze! Splits the tree right down the middle. I've never seen an evergreen split (probably do though) but hardwoods split. A temperature of about -50F one year where I was going to school killed 25-50 of the hardwood trees.

[Enoch Root]

I think the old wisdom was it "went to the roots". The tree is driest in winter. Doesn't really answer your question though, because there is not "no moisture" in the trunk.

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[Andy Dingley]

Obviously it's both yes and no, depending.

Sap is resistant to freezing. Increasing the sugar content in sap makes it more resistant to freezing, which is why you can't get maple syrup in a place with mild winters.

Free water may indeed freeze. Freezing water expands, rupturing cell membranes. So in the Fall period, some trees pump water outside the cells by osmosis, leaving the cells themselves almost dry. If there is any freezing, this happens _between_ the important parts, not inside them, and there's simply some temporary distortion.

Some species have a thick corky bark layer that can freeze without damaging anything important. Ice is a better insulator than water, so the core of the tree stays unfrozen.

The tree may indeed freeze and die. Sometimes you even see branches that have been split open by this.

[George]

Freezing point depression - why salt melts snow - has been covered. But below around 15 F they switch to sand only, because salt water can freeze. So even trees with anti freeze can run out of luck if it gets cold enough. Less overall water, greater amount of solute all to no avail. Denser woods are more vulnerable than those which have some larger vessels to collapse and take up the pressure from the expanding ice.

Evergreens get needle burn real bad in cold weather, depending on species. Sort of like freeze-drying the vegetation.

[Guess who]

I've done a lot of tree-felling/log-cutting. So much so I had to purchase a new saw recently. The old one finally gave up the ghost. I've also done some wondering in my time. I'm here to tell you that is is a VERY bad habit to do both at the same time, except to wonder why you are doing that in the first place and not lying on a nice warm beach. . . . Wrt the freezing, it is a mixed reaction of events. Trees being living things are complex. The sugars and other chemical composites form a natural antifreeze, and the cells react to such change. Not all trees can survive -40, so it's a matter of the chemistry of that particular plant, and plants in all their variety are incredible chemical factories.

[James "Cubby" Culbertson]

Oh yeah, them chainsaws can sure pack a punch if you're not careful. It was actually as I was walking to another pile of logs that I thought of this question. While cutting, my mind is on nothing but the cutting, similar to using any power tool! Cheers, cc