Polar Vortex: The new four letter word!




Hi folks, this is my first attempt at writing for the blog (I think that’s what it’s called) so please bare with me. Dan has been politely nudging me to get something on here for quite some time, it’s been like getting a cat to take a bath.

Here in Wyoming our weather is fickle to say the least. At the top of the list of atmospheric delights is our wind, if you can’t love or at least tolerate it you’ll have to move because it’s a way of life (everyone here has one leg longer than the other from leaning into the wind). Data USA.com compiled from 2008-2012 records the average wind speed for Douglas or Converse County was 21.23 MPH, and the highest average in Wyoming was 22.64 MPH.  The old saying: “if you don’t like the weather in Wyoming just wait an hour, it will change,” is really not that far off.

This Fall I spent every weekend in Cheyenne, helping my father in law who was in hospice, and trying to get my trees in the cold frame and gravel bed after work, or when we got back to town. In October the weather was unseasonably warm; November started out the same at 40 to 60 during the day down to the 30s to the teens at night. I got back to town Sunday the 9th, and worked until around 11:30pm in a tee shirt getting the last of my trees in the gravel bed. The temperature was 60 degrees when I went to bed at 12:00am. When I woke up to go to work the temp was 15 degrees and dropping to 7 degrees at midnight; a 43 degree drop in 24 hours! The joy doesn’t stop there; in the next 24hrs we went from 7 degrees to -10, then the final blow – 25 degrees at 7:00 the morning of the 13th with a 3.5 mph wind which gives us -33 wind chill! Without figuring in the wind chill that’s an 84 degree drop in 79 hours!

Where in the heck is this honyock going with this shivery tale of woe you ask? Well after the polar vortex (I stole this from the weather channel) let up, we went back to normal temps, 30-40 during the day and 10-20 at night. I noticed a few of the Ponderosa pines I’ve had for two years that had strong growth over the summer, most of the needles were all brown on a couple and the other affected trees had certain branches that the new needles were brown and most of the old needles were still green. My first thought was that I had lost these few trees to some form of ignorance on my part, but upon closer inspection I saw that all of the new buds still look good and healthy.

Down With The Brown 021

When driving around Douglas and Cheyenne I saw a very large number of brown pine trees, all were landscape trees, some slightly mottled and others with 90 % brown needles. No junipers, spruce, or white pines seemed affected. I brought this up to Dan the next time we got together and he had also noticed all the brown pines in town, although all of the pines at his house were normal. We both thought it had to have something to do with the sudden drop in temperature a few weeks back.

Down With The Brown 002


Then low and behold, an article was written in the Casper newspaper pertaining to the large amount of pine trees in town that looked like they had suddenly died. The article confirmed what Dan and I had surmised. With the relatively mild temperatures we were having, the pines were slowing down in preparation for dormancy, but some still had quite a bit of water in their needles. When the temperatures dropped 84 degrees in three days, the needles that were still all fat and sassy froze. The water expanding raised havoc with the cell structure in the needles, much like a human finger with frostbite turning black; people or plant the jig is up! What was really stickin’ in my gizzard was the question “why?”… out of 20 ponderosas in the winter gravel bed, three have 85% of their needles brown, four others were affected but on random branches, and the buds on all of them look fat and healthy. The other thirteen look as they should!  Upon deeper reflection, I realized that of the pines affected in my winter gravel bed, the three worst hit were ones I had left buried through the summer, and those were potted in diotamatious earth (Floor dry). These trees were going to be repotted into pumice this spring.



Now after talking with a few folks and adding it all up in my addled noggin, I came to the following conclusion. The trees most affected were growing strong through the summer, and I suspect they were probably still pushing roots; they were somewhat insulated from being buried during the cold nights. These trees maintained a more even temperature so they hadn’t slowed down as much as the other trees I had sitting on top of the ground. I think with the trees above ground the roots had gotten colder and as a result the trees were shutting down for winter and didn’t have as much water up in the needles. This is all conjecture on my part, but it seems to fit.

Down With The Brown 014

My lesson taken from this is to unearth all of my trees this spring; and next fall I plan to taper off my watering and lean on the dryer side quite a bit more than I did this fall. So, if as unlikely as it would be to have another 80 some odd degree drop in three days, maybe I will be ready for it! I am far from a learned arborist; most of what I know has been the proverbial trial and error method (alias, the pain and suffering method) over the past 17 years. Dan and I have taken some of Michael Hagedorn’s seasonal classes (and I would highly recommend them). The main thing I have figured out is the more I learn the more I realize how little I really know!

Thanks for enduring my prattle and may your bark be thick.




4 thoughts on “Polar Vortex: The new four letter word!

  1. As one nurseryman once said: “It is not how cold it gets, but how it gets cold.”
    My experience is that when the needles are brown and the bud looks OK, it will still die.
    The explanation I have heard for such cold injury is that there is not enough water in the needles due to the intense cold interfering with xylem flow.

    • Hopefully it makes it! I know the feeling. There are a few of my maples that I’m keeping a close eye on. Let me know if you need any help with it this spring. 🙂

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