Monday, November 15, 2010

Lightning Tree

There are hundreds of trees at Blue Jay Barrens that display enough unique characteristics to be individually recognized anywhere. In a forest without a stressful past, the trees would probably have more uniformity. I search these odd trees for clues to their history that would help explain why there are as they are today.

The top of this Tuliptree was lost so long ago that its remnants have long since vanished into the forest floor. Given the time involved, you would think that growth from the lateral branches would be much more extensive. A healthy tree could have put on that much growth in just a few years.

A look at the base shows the tree to be in less than perfect health. Loose bark hangs all around the tree and it’s hard to find any living material at all. The living top is evidence that there is still a functioning cambium layer somewhere on this trunk, but it must be a minimal amount that can only support a greatly reduced top.

Here’s the signature curve displayed by so many of Blue Jay Barrens’ large trees. Following the curve down the trunk is a scar from an old lightning strike. While most of the bark is partially detached from the trunk, the area along the scar appears to be alive and well. This may well be the lifeline to the tree top.

It’s hard to predict how lightning will impact a tree. Exterior moisture on the bark, extent of sap flow through the cambium, and wetness of the soil can all influence whether the electrical surge passes through or along the exterior surface of the tree. Some of this bark appears healthy and some is just draped over the trunk. Sap may have to follow a maze to reach the top of the tree.

On another side is some more serious lightning damage. Under certain conditions, a lightning strike will superheat the moisture within the tree, causing it to turn to steam. The pressure resulting from this sudden transformation from liquid to gas can cause the bark to explode from the tree. This is the type of strike that causes the greatest visible damage to a tree.
I witnessed a strike like this when I was in High School. I’d been out fishing and was hurrying across a field, trying to get home before a storm arrived, when lightning struck a large fence row tree about 70 yards from me. When the lightning hit the tree, I hit the ground. Pieces of bark made it out to where I was and I felt a heat flash on my face and arms. I just stayed there and let the storm roll on over me. I had plenty of time to think while I was laying there and what I thought was that if I had to ride out a storm in the open, I should have just stayed at the lake where I could still be fishing. Since then I’ve become much more adept at judging the speed of approaching storms and haven’t found myself accidentally out in a storm since then.

4 comments:

  1. Trees can tell quite a story! My favorite is a wander through the forest and coming across a patch of twisted trees, caused by excessive amounts of snow year after year after year while the trees are just developing. ~karen

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  2. Thanks for my science class once again. Fascinating information every time I come here.

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  3. Hi Steve...I'd say your lucky that lightning hit that tree instead of that crazy kid running across the middle of an open field with a lighting rod (fishing pole) in his hands! : }

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  4. Hi, Karen. We don’t get enough big snows to cause that effect here. A huge snow is more likely to lay a patch of trees flat to the ground or leave them bowed in big arches.

    You’re welcome, Lois.

    Hi, grammie g. I’m afraid that kid had delusions of immortality and didn’t believe anything bad would really happen to him.

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