[FrogBurger]

We move on, now were at the Red Forest. So called because on the night of the accident, the whole forest glowed red.

Sorry, your guide BSed you to the hilt. There is no known process to make something radioactive glow red unless you use special coats, etc. You can detect the light blue glow of radioactive metals, especially in a water pool, but certainly not a piece of wood.

Red Forest was either a code name after the incident, or a pre-existing name.

[Caipirabob]

All the chlorophyll turned red as the trees died from the radiation. The trees literally turned red. That's where the name came from.