It is uncertain how such shapes were created. The trees have now about 70- 80 years.
The most popular theory says that they were shaped this way by people who cultivated the trees for carpentry purposes. Other theory says that they were shaped like that because of the tanks that were standing there during the WWII.
Of course there are theories about UFO and such impact.
In other places (see link below) there are theories about positive and negative energies that collide, but...
the truth remains unknown...
Also thanks to
you can see there's similar forest in Kaliningrad -> [link]