Interestingly, radiation does not cause things to mutate, glow green or gain additional limbs (tree pun). It simply causes them to die, or grow cancer. I guess you could consider cancer a mutation, but i just consider it damage. The trees will not be gaining the genetic code of the scientists involved in the nuke tests in the 40s, thus creating an unstoppable race of superintelligent homicidal trees, bent on stopping communists. Unfortunately.
If that happened, I bet some other scientists could remutate the trees to create an unstoppable race of superintelligent homicidal trees bent on stopping terrorists instead of communists. This would be very advantageous for the current presidential administration. Since communists came to be known as 'commies', does that mean terrorists are 'terries'? And what effect will this have on the emotional state of people named Terry? Only time, and thousands of subterranian barrels of radioactive tree mulch, will tell.