The part of Siberia where the tigers live isn't the stereotypical taiga you are probably imagining. Google "Ussuri broadleaf and mixed forests", "Sikhote-Alin Nature Reserve" or "Ussurisky Nature Reserve". It's very far south, far enough that the boreal taiga is replaced by a temperate forest, not unlike those in China, Korea or Japan.
redditfejs t1_jec4r8g wrote
Reply to Eli5: why are there tigers in Siberia but not in Scandinavia? by chosen-username
The part of Siberia where the tigers live isn't the stereotypical taiga you are probably imagining. Google "Ussuri broadleaf and mixed forests", "Sikhote-Alin Nature Reserve" or "Ussurisky Nature Reserve". It's very far south, far enough that the boreal taiga is replaced by a temperate forest, not unlike those in China, Korea or Japan.