Longleaf “S”curve growth

[Hendrix]

Has there ever been a study or any information available for why at any given location a planted stand of longleaf  will have random longleaf trees planted at the same time grow in a severe c or s curve fashion. Have 7 and 15 year old trees and the percentage is low at each location but the same otherwise. Could it be genetic? I have never seen loblolly do this. Thanks for any info

[TreefarmerNN]

I've seen it in my long leaf as well.  I've wondered if it was just because some of them are tall but very limber and get bent in a wind and then grow toward the light again.  They are certainly a different tree to work with than loblolly, that's for sure.