Well Playford, NO it isn't the best but there are limits ya know!
OK on a more serious note, I (personally) don't believe trees get cancer. I have a theory on the cause of cancer, but thats a completly differant topic. The fact is that there has been little research into what is good for the trees. Ironically the rainforest is considered the drugstore for humanity, and we take, take take, and never give back.
A couple years ago was the first time ever that the gnome of a Black Poplar was mapped, and as far as I know they are still shocked at what they found. In respect to the lower plant forms, we have studied them to death, ALL for the benefit of making them MORE productive, or prettier for planting around the house.
As far as the plants changing, it happens, the same with people. In the post war years, the Japanese people have gained dramatically in height. We ALL co-exist in a thin membrane called the atmosphere, it is only logical that we ALL will adapt or die.
I hope for the trees, that they can be spared the horrors of human diseases.