According to a couple of webpages in Polish, the trees were planted around 1930. One hypothesis states that they were bent by a carpenter to use for furniture making. They were cut and forced to grow horizontally for a while before being allowed to grow upright. But nobody's really sure.
You have read this article Plants with the title Gryfino Forrest, Drunken Trees. You can bookmark this page URL http://lettersfromladygodiva.blogspot.com/2012/01/gryfino-forrest-drunken-trees.html. Thanks!