[joe kuhn]

My son asked me this and I don't know the answer. Temps will be -20 degrees tomorrow. I think it's a good question. There's a little bush right outside our front door the dog is chewing on and you can easily see the moisture in the pieces.

 

[skeeljc]

Because tree sap is not 100 percent water.

Jim Skeel

 

[Dougbbbb]

Three ways according to experts

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's 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.

 

[Stl Flyn]

Tomorrow morning when it is still dark out, walk outside and listen. If you are close to woods, or a wood lot, you will hear the trees popping, and cracking. Even though the moisture is lower in winter, whatever is still in there will freeze, and expand.

Used to hear it all the time, when up north deer hunting in the -15 degree temps. Especially the Maple trees.

 

[joe kuhn]

Dougbbbb, Thanks so much for your post. I don't get the third part. Can you explain another way?

We will be listening to the trees come Monday.

 

[Shooting Sailor]

Trees will freeze, if the temperature drops far enough, rapidly enough.

I was hunting in northern British Columbia several years ago, when the temperature went from about 35 degrees Fahrenheit, down to 35 below 0, in under 12 hours. It had been mid 30s for a couple days before the drop, so the processes listed by Doug above hadn't had time to occur. The morning came, bright and beautiful, and you could hear trees exploding all around, for about 2-3 hours. The first couple sounded like small caliber rifles, right across an old logging road from me, then they varied from firecrackers to heavy shotgun loads in volume.

 

[timberfaller]

Fell "frozen" trees every winter I fell timber. Pine,fir,spruce usually by December were froze clear thru.

They would actually dull a chain faster then when they were soft and alive!!

Cured the problem by going with full comp chain in the winter months and full skip in the summer.

Why do they freeze? IT gets COLD in the winter.

 

[joe kuhn]

Excellent info. Will pass on to son. Thanks

 

[Tron]

They do freeze and when they thaw, the sap runs. That's where Maple syrup comes from. So, the next time one of your kids won't let go of your Eggo, give them an education.

 

[noknock1]

So when is the best time to trim trees or does it not matter? I figure the dead of summer will stress the tree, but what about spring or fall?

 

[lots of 24's]

I know I have heard them pop and snap when it suddenly got really cold. I remember deer hunting when I was kid one day, they were so loud, I swear they sounded like gunshots more than a few times. Scared the crap out of me most of the time, all day long. Man that was one long, really cold day.

 

[BAD 303]

Best time to trim trees is any month that has an "R" in it.

 

[timberfaller]

Around here in the PNW its generally after the first heavy frost and winter sets in(cold). The fruit trees are considered "dormant" then and the pruning crews are sent out.

 

[RWT]

Citrus trees will sure freeze and split the bark from expansion.

Years ago we lost 20 acres, the freeze damaged them so much they were not worth salvaging, and that was just in the teens.

 

[SPACE GUN]

The best time to trim trees is when your pruners are sharp!

 

[CalvinMD]

I always thought they didn't freeze cuz dogs pee on them