Trees talk and kill.

But don't worry, trees that I am talking about won't kill humans but their predators only.

I happen to read an 18 year old issue of Science Frontiers that mentioned about killer trees that talk. By 'talk', I mean they send out signals to other trees of their own species that there is a predator at large.

The predators are 'Antelopes'.
The trees are Acacia.
The talking method is sending out a signal through air not in the form of sound buy by a unique method.

Here it is:
Antelopes nibble at Acacia trees. The trees then produce tannin in quantities that are sufficient to kill the antelopes within two weeks of eating the leaves.

To warn other acacia trees, the first victim tree emits ethylene into the air which can travel up to 50 yards. The ethylene warns other trees of impending danger, which then step up their own production of leaf tannin within just five to ten minutes.