Wednesday, July 27, 2016

A Pine can have lightning scars that run down the trunk. Why doesn't an Oak?

 by Cecilia Catron, Tarflower Chapter of the Florida Native Plant Society

(reprinted with permission from the August 2016 issue of Tarpaper)

Pine Scar
 When days are hot, as they have been for the past month, it seems like a sensible idea to lie in or around the pool all day, like a motionless alligator. Curds of bright, white thunderheads rise higher and higher, expanded by the increasing heat. Gradually air pushed from the east and west coasts meets in the middle of the peninsula. By mid-afternoon it becomes charged by the collision of the fronts and summer lightning is created, with or without a storm.
Knotty Oak


Have you ever noticed a stripe spiraling down the trunk of a pine tree where lightning has stripped the outer bark off? You may have also noticed there is no such stripe on the trunk of an oak tree. Oaks and Pines, both dominant here in central Florida, have different lightning survival strategies. Most pine species have long, straight trunks. They are relatively fast-growing with soft wood. Oak trunks on the other hand are often twisted and full of knots. They grow more slowly (except Laurel Oak, Quercus laurifolia) and the wood is very hard, dense, and heavy. 

Lightning is attracted to the tallest tree, regardless what species it is. Energy is conducted down the trunk of a typical pine with little to stop it since the cells are constructed in long, continuous rows. Knotty oaks  on the other hand do not have such unobstructed cellular highways. When a knot is struck it may explode, but a lightning bolt's energy is spent before it can progress down the trunk, limiting damage. Good planning, oaks. Also a case for organisms that create knots on oaks - part of the ecological give and take. New pines grow relatively quickly to replace trees that are destroyed, which is also a viable strategy.

 Be that as it may, never take shelter under any tree to escape a storm. Especially here in Lightning Alley nature can put on an awesome show, but it's important to remember that a tree may be a target.

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