"What had been a Quidditch match turned swiftly into a human versus tree battle, which the wizards won only after seven hours’ hard fighting. Nenad was not prosecuted as he had been killed early on by a particularly violent spruce." (Pm)
The West Siberian Plain was the location of the 1809 Quidditch World Cup final between Romania and New Spain (now Mexico). This final is infamously known as the Attack of the Killer Forest – and was the scene of an horrific seven-hour tree vs wizard battle (Pm).
The West Siberian Plain is a large area of lowland in the west part of Siberia. The Russian name is Zapadno-sibirskaya Ravnina (За́падно-Сиби́рская равни́на). It lies between the Ural Mountains, the Yenisei River in the east, and by the Altay Mountains on the southeast. The land is extraordinarily flat and sparsely populated. It has some of the world's largest swamps and floodplains, but there is no mention on its Wikipedia page of Quidditch or any other wizarding sport activity taking place there (Wikipedia).
From the Web
Writing by J K Rowling on Pottermore: History of the Quidditch World Cup
Harry Potter Wiki: Quidditch