So as you know, ~50% of Jpn is contaminated by reactor fallout, after they exploded..
The cesium falls ontop of the soil , then the rain washes it down.
The TREES pick it back up and during Spring, it Comes out in radioactive pollen.
This is a huge problem, because Pollen is designed so perfectly to carry in the wind, and are now a new source of Hot-Particles. The Cedars of Jpn are essentially re-volatilizing the contamination.
Cut down all the trees ?