Since 1986, a thousand square miles of eastern Europe is off-limits to average people. That is because of the nuclear accident at Chernobyl. Ironically, the fact that people aren't allowed in the Chernobyl Exclusion Zone is what turns the zone into a sanctuary for wildlife, most notably in the Red Forest:
One of the Red Forest's immediate concerns is that when the reactor failed, it contaminated the soil, water and air with 20 times as much radioactive material as the bombings of Hiroshima and Nagasaki.
In this alternate scenario, there is a different Red Forest, caused not by the meltdown of a nuclear power plant, but by the nearby explosion of a nuclear explosion. As the title suggests, we will be using the Tsar Bomba for a demonstration, for there was no greater nuclear bomb in human history. The explosion had a blast yield of 50 megatons of dynamite, almost 2400 times the size of the explosion that destroyed Nagasaki and more than 3,000 times the size of the one that destroyed Hiroshima! And to make matters worse, there were plans for a Tsar Bomba big enough to blast off 100 megatons of TNT!
Let's say that was exactly what happened--a 100-megaton explosion annihilated a city. A Red Forest soon sprouted from the barren, radioactive crater. Animals that were endangered elsewhere are now abundant in this one spot. Compared to the Red Forest of Chernobyl, how much radiation from the explosion would the trees of this Red Forest store?