Russia contains the world’s largest continuous area of boreal forest.
The Russian taiga stretches across Siberia and the Russian Far East, forming the largest land biome on Earth. Boreal forests are dominated by coniferous trees such as spruce, pine, fir, and larch, and they experience long, cold winters.
Russia’s enormous east-west extent allows the taiga to form a nearly continuous belt from the Ural Mountains to the Pacific coast. The region also stores vast amounts of carbon and provides habitat for species including the Siberian tiger, brown bear, lynx, and reindeer.
Canada also contains extensive boreal forest and is often mentioned alongside Russia in global forest comparisons. The question concerns the largest continuous national expanse, not the country with the greatest percentage of its land covered by forest.