Once upon a time, in a place pretty far away, there was a forest where the screwy old trees grew sideways.
All 400 north-facing trees had been warped for as long as the residents of Gryfino on the Polish/German border could remember, and yet no one knows why. Perhaps their growth was stunted and then magically corrected itself: a coincidental combination of light density, soil erosion and nutrients. Maybe they were genetically engineered for better carpentry. Who knows, really? Personally, we're hedging our bets on the former, or aliens, or something.