I find this disturbing because I have great respect for trees. It seems to me that if all the trees disappeared, the planet would become incapable of supporting human life except in artificial bubbles, and where would the wholesome air and beauty of nature be then? If, on the other hand, all the humans disappeared, the trees would flourish and the health of the planet would become fully self-regulating again. Is it not reasonable to postulate, therefore, that in a natural sense at least, the tree is more important than the human?
As for the question of whether trees are sentient, I suppose it all depends on whose beliefs you choose to follow.