The relevant paragraph is actually this: And while radiation and other types of DNA damage can cause tumours in plants, mutated cells are generally not able to spread from one part of the plant to another as cancers do, thanks to the rigid, interconnecting walls surrounding plant cells.

Plants also lack a closed circuit circulatory system designed to accommodate autologous cells. So not only can the cells not get out of their walls, there wouldn't be much of anywhere to go if they did.

In order for a cancer-like mutation to kill a plant it would probably have to cause mechanical damage. Tumors completely circling the trunk of a tree might have an effect like girdling the tree and kill the tree. A tumor growing in the center of a stem might compress the xylem and phloem enough to choke them off.

This kind of fatality happens with humans, too, even if the cancer doesn't spread beyond the origin site.

Maybe this has some weigth> "the nuclear accident was far less destructive to the local ecosystem than we were. In driving ourselves away from the area, we have created space for nature to return."

Derailing, it irks me to see plant growth described as "more organic" than animal growth.

Similarly I always feel little stitches from rhetoric use of the perceived degree of organicity a thing possesses in contrast to another. It's such a vague metaphor. I guess what usually counts as more organic is: - stuff that decomposes, is not ignored by destruents and stinks - stuff that is complex and semi-random, no central, overall plan

So maybe it's the last point. For an animal you need a thorough layout, like for a cathedral (but, well there are also Gaudí's which aimed to be more "organic" - all these metaphors are so messy, maybe natural language is too organic)